Annual Conference THE UNIVERSITY OF TENNESSEE COLLEGE OF VETERINARY MEDICINE THE UNIVERSITY OF TENNESSEE COLLEGE OF VETERINARY MEDICINE

Transcription

1 THE UNIVERSITY OF TENNESSEE COLLEGE OF VETERINARY MEDICINE 2018 THE UNIVERSITY OF TENNESSEE COLLEGE OF VETERINARY MEDICINE Annual Conference January 26-28, 2018

2 2018 THE UNIVERSITY OF TENNESSEE COLLEGE OF VETERINARY MEDICINE Annual Conference This is an interactive PDF! You may choose to print this document, scroll through the PDF to view each topic sequentially, or simply navigate through this PDF using the embedded links that are on every page. To jump to any of the topics listed below, just click on either the title or the page number and you will be automatically taken to that page. To return to this table of contents, click the link in the top right corner of each page that says BACK TO TABLE OF CONTENTS. VETERINARY PRACTITIONER PROGRAM - JANUARY 26-28, 2018 Asset Protection: How Veterinarians Can Become Invincible to Law Suits and Save Thousands in Taxes Mr. L. Oxenham...4 Going, going, gone: Diagnosing and Treating Complicated Keratitis Dr. D. Hendrix Releasing the Kraken: A Fear Free Experience Dr. K. Primm...31 Everybody Benefits from Fear Free Dr. K. Primm No Really? How Do I Make Fear Free Work? Dr. K. Primm...40 Small Animal Infectious Disease: Which Antibiotic, When and for How Long? Dr. J. Sykes...44 Leptospirosis Update in the US Dr. J. Sykes Vector-borne Diseases Dr. J. Sykes Frustrating Fungal Diseases Update on Diagnosis and Treatment Dr. J. Sykes...67 VETERINARY TECHNICIAN PROGRAM - JANUARY 27, 2018 Releasing the Kraken: A Fear Free Experience Dr. K. Primm...74 Everybody Benefits from Fear Free Dr. K. Primm No Really? How Do I Make Fear Free Work? Dr. K. Primm Under Pressure: Blood Pressure Management in the Anesthetized Patient Ms. N. Shuey LVMT...87 Immune Mediated Diseases: Challenges and Treatments Ms. E. Littleton LVMT, VTS(ECC)

3 VETERINARY PRACTITIONER PROGRAM PROCEEDINGS January 26-28,

4 4

5 5

6 6

7 7

8 8

9 9

10 10

11 11

12 12

13 13

14 14

15 15

16 16

17 17

18 18

19 Going, Going, Gone: Diagnosing and Treating Complicated Keratitis Diane Hendrix, DVM, DACVO Professor of Ophthalmology, University of Tennessee CORNEAL ANATOMY The cornea is composed of three main layers. The outside layer is non-keratinized squamous epithelium which is 5-7 layers thick. The stroma makes up 90% of the corneal thickness and is primarily collagen. The stroma can take months to rebuild when damaged. The collagen is formed from keratocytes (modified fibroblasts). The endothelium with its basement membrane (Descemet s membrane) is the inside layer. The canine and feline cornea is about 0.5 mm thick. Corneal innervation is via the ophthalmic division of the trigeminal nerve. Superficial injury is often more painful than deep injury as the pain receptors are superficial. Brachycephalic breeds have fewer nerve branches than dolichocephalic and mesocephalic breeds. Corneal vascularization When blood vessels invade the cornea, they begin from the limbus. Corneal vessels indicate active chronic disease. It takes one week after the initial injury for blood vessels to begin to grow, then they grow 1-2 mm per day. RECOGNIZING THE COMPLICATED ULCER: Infected superficial ulcers are usually rounded with no sharp edges. Have associated edema, cellular infiltrate, and uveitis. Deep, mid and superficial stromal ulcers have varying depths of stromal loss. Often there is more corneal edema and cellular infiltrate than is seen with noninfected superficial ulcers. Most have obvious uveitis. Descemetoceles are deep pits in cornea in which the stromal walls are positive for fluorescein but floor (Descemet s membrane) is not. Corneal perforations often have fibrin, blood or iris seen protruding from the cornea. Melting ulcers have a gelatinous appearance that often protrudes above corneal surface due to expansion of stroma. There are variations in severity. Dogs that classically get complicated, infected ulcers are brachycephalics, have KCS, or are on steroids. Chronic non-infected ulcers are associated with KCS, entropion, ectopic cilia, etc. Indolent ulcers are chronic, have a loose edge of epithelium, and have very few to no PMNs seen on cytology. Facets are re-epithelialized stromal ulcers. A complete examination is required for all ulcers as determining the inciting cause is paramount. Most stromal and deep ulcers are infected with bacteria, others are caused by keratoconjunctivitis sicca, or very rarely fungal infections. Fluorescein stain is still the diagnostic modality of choice. 19

20 Possible Inciting causes are listed below. But when the ulcer appears to be complicated (except for indolent ulcers) a culture and cytology are indicated. All deep ulcers should be gently scraped with blunt end of a scalpel blade for cytology and the ulcer should be cultured for bacteria. Interpreting cytology and culture results Use Diff Quick or similar product for in-house staining. Lots of PMNs are indicative of a complicated ulcer. The absence of bacteria is not evidence that an ulcer is not infected, but the presence of many bacteria is confirmation of infection. If any bacteria grow from a good culture sample, ask for a sensitivity. Medical therapy Therapy of choice for a noncomplicated or indolent ulcer is still triple antibiotic TID-QID. Atropine, 1% ophthalmic solution or 1% ophthalmic ointment, BID-TID to effect. And treat the inciting cause. For complicated or infected ulcers Tobramycin/cefazolin (cefazolin powder used for intravenous administration is mixed with artificial tear solution to make a 33 mg/ml solution that is good for 2 weeks when refrigerated, has a basically Gram positive spectrum). Gentamicin and tobramycin should be used with cefazolin to increase the bacterial spectrum. Ciprofloxacin or other fluoroquinolone Administer q2h until the ulcer stabilizes then q4h. Tapering frequency is partially dependent on culture results. Serum q2h until stabilization then taper. Atropine is administered as needed and is dependent on degree of uveitis and response. Recognizing response to therapy Melting has ceased to progress in depth or diameter Epithelium has begun to grow into ulcer bed Uveitis is lessening Increased depth to ulcer is not always a bad sign Surgical treatment Conjunctival graft placement is necessary for the best chance of vision for eyes with descemetoceles or iris prolapse. The most useful surgical technique for these cases is pedicle conjunctival grafting. Grafts provide much needed structural support and a healthy blood supply that promotes healing and provides several serum anti-collagenase compounds (e.g., alpha-2 macroglobulin and alpha-2 antitrypsin) to retard corneal melting. Generally, conjunctival grafts are referable procedures. Using an operating microscope with microsurgical instruments and experience helps ensure a better prognosis and outcome for the patient. In all varieties of conjunctival grafting an attempt should be made to harvest only the thin conjunctiva, as adherent Tenon's capsule will result in graft retraction 2-3 days postoperatively. The bed of the ulcer should be gently scraped with a scalpel blade to ensure that all epithelium has been denuded from its surface. This will help promote graft retention. Also, all necrotic 20

21 corneal stroma should be removed prior to placing the graft. Pedicle grafts can be used for essentially any ulcer except those that occupy a large portion of the cornea (i.e., approximately 75% of the diameter of the cornea) or those that are melting so rapidly that the sutures would be in danger of dehiscence. Six to eight weeks following graft placement, the graft is incised at its limbal attachment and at the edge of the ulcer. Some advocate therapy with topical steroids at this point to accelerate reduction in scar tissue, but the ultimate degree of scarring will probably be the same with or without the use of steroids, and I do not use them. After placing a graft medical therapy (minus serum) must also be used as described above. Placing a conjunctival graft: The diameter of the area to be covered is determined, as this will determine the width of the pedicle. An incision using tenotomy scissors is made in the conjunctiva perpendicular to the limbus leaving about 3 mm of conjunctiva at the limbus then extending the incision the width of the lesion plus 3 mm. For a centrally located lesion on the right eye, this incision is begun at the 9 o'clock position. The incised conjunctival edge is grasped with fine forceps and tenotomy scissors are used to undermine the conjunctiva dorsally. A second conjunctival incision is made parallel to the limbus from the lateral extent of the first incision and extended dorsally. This incision also begins at the 9 o'clock position (incisions should be mirror images to those just described for lesions of the left eye). The 3rd incision is then made parallel to the limbus and 2 mm peripheral to it; from the medial extent of the first incision and extended dorsally. It is continued dorsally to a point vertically above the medial edge of the lesion. The pedicle should be hinged dorsally. The pedicle is then rotated down over the lesion and sutured to the edge of the lesion. If the lesion being covered is a melting ulcer, the necrotic edges should be debrided to healthy cornea so that there will be a healthy edge on which to suture. Simple interrupted sutures should be placed every 1-2 mm all the way around the graft. If perforation has occurred, an additional suture should be placed through the rotated arm of the pedicle, taking care not to place the suture in such a location that major blood vessels are ligated. If this "pedicle arm" suture is needed, it is usually easiest to place it first. The precise location of the pedicle can be altered from the scenario above to facilitate conjunctival harvesting. However, the final direction of the pedicle should not stray from the vertical for more than 45 or blinking will encourage dehiscence of the pedicle. Also, for very large lesions, placement of a temporary lateral tarsorrhaphy will help prevent dehiscence; this can be taken down in one to two weeks. BioSIS (porcine small intestinal submucosa) and ACell (porcine urinary bladder matrix) are sutured directly to the cornea and serve as collagen scaffolding that maintain and support the corneal healing environment. They can be used alone or in combination with a conjunctival graft. Enucleation may be necessary due to financial constraints of the owner, lack of specialized instruments of the veterinarian or due to the severity of disease. 21

22 Etiologies of corneal ulcers: Trauma Often there is a history of trauma (cat scratches are common). Foreign bodies can cause ulcers, especially if they become lodged under the third eyelid. Also, toxins can cause ulcers. Simple flushing is often ineffective for removal of corneal foreign bodies, but using a saline or eye wash filled 6 cc syringe with a 25 g needle with the needle shaft broken off can often generate the force needed to remove most foreign bodies. Entropion is an inward rolling of the eyelid margin. Usually entropion involves the lower eyelid but it can occur at the lateral canthus or upper eyelid. There is a breed predisposition for Shar peis, bulldogs, Rottweilers, and chows. Entropion can be conformational, spastic or cicatricial; this must be determined during the examination to select the appropriate therapy. Conformational entropion is due to a disproportionate size of orbit and globe position. The entropion does not correct after applying topical anesthesia. Treatment for conformational entropion is the modified Holz Celsus. This procedure can be applied to any area of the eyelid - lateral, middle, upper, or lower. Treat any secondary ulcers medically or surgically as indicated. Spastic entropion occurs secondary to ocular pain. The pain causes the dog to retract the globe thereby allowing the eyelids to roll in. This corrects with topical anesthesia. When spastic entropion is diagnosed a Schirmer tear test and fluorescein stain must be done to help determine the cause of pain. Treatment for spastic entropion involves treating the primary cause. Sometimes tacking the eyelids may be necessary. Tacking the eyelids is done by placing 2 or 3 vertical mattress sutures in the skin of the eyelid with 4-0 or 5-0 polyglactin 910 to evert the eyelid. Cicatricial entropion occurs when chronically spastic tissue scars or there is scar formation from trauma. Treatment for cicatricial entropion usually requires surgery. It may require the modified Holz Celsus or it may involve excising the scarred tissue. Puppy entropion occurs in shar pei puppies. This is not treated surgically; rather 2-3 vertical mattress sutures are placed to roll out the eyelid. 4-0 or 5-0 polyglactin 910 can be used and left in place until it dissolves. Ectopic cilia - Ectopic cilia are cilia that originate from the tarsal glands and emanate from the palpebral conjunctiva. Clinical signs may not occur until middle age. To locate an ectopic cilia, use magnification to look at the palpebral conjunctiva approximately 4 mm dorsal to the eyelid margin. Ectopic cilia can be very difficult to see. They are usually at the 12 o clock position on the upper lid. Specific Treatment - Excise cilia en bloc from conjunctiva. Warn owners that more may grow. Look closely for more ectopic cilia that may not yet be causing clinical signs while the animal is anesthetized. 22

23 Other similar disorders such as trichiasis or disticia may cause corneal ulcers, slow their healing or cause keratitis with pigmentation, vascularization and scarring. Keratoconjunctivitis sicca is a disease resulting in corneal ulcers, keratitis and conjunctivitis caused by a lack of aqueous tear production. KCS is the single most common cause of conjunctivitis in dogs. Clinical signs: corneal ulceration (superficial or deep), hyperemic conjunctiva, mucopurulent discharge, keratitis with pigmentation, corneal vascularization, scarring, and a dry appearing cornea. Diagnosis is made by observing the clinical signs and having a Schirmer tear test value less than 12 mm of wetting/minute. Normal tear production is mm/minute. If the tear production is between 10 and 15 mm/minute then make the diagnosis based on clinical signs or recheck tear production on another day. The most common etiology is immune-mediated. It is often seen in cocker spaniels, bulldogs, lhasa apsos and many other breeds. Other etiologies are canine distemper virus, sulfa drugs, etodolac, facial nerve palsy, trigeminal nerve palsy, iatrogenic (removal of the nictitans gland), chronic conjunctivitis, and lacrimal gland agenesis (especially seen in toy breeds). Both topical atropine and general anesthesia can cause temporary KCS. Treatment Replace the tears using artificial tear ointment. Artificial tear solution has such a brief contact time that it is rarely beneficial in veterinary medicine. High viscosity polymers help in corneal wetting and prevention of evaporation but they can be quite expensive. Depending on the tear production, may use as often as QID. Create more tears by using cyclosporine A. Cyclosporine is an immunosuppressant. It suppresses T-helper cell (CD4) activity that is thought to cause immune mediated KCS. Cyclosporine A is manufactured as Optimmune and is also compounded as a 2% solution. It is used BID. Cyclosporine A works in approximately 75% of cases. It may take as long as 8 weeks for the drug to work. Once the tear production has increased you may consider discontinuing or decreasing frequency of artificial tears. LIFE LONG treatment is needed in most cases. Topical antibiotic ointment, neomycin, polymixin B and bacitracin, helps treat the secondary bacterial conjunctivitis and corneal ulceration that is commonly associated with KCS. For treatment of conjunctivitis or a superficial uncomplicated ulcer use TID to QID. INDOLENT ULCERS Indolent ulcers have many different names: Spontaneous chronic corneal epithelial defects (SCCEDs), boxer erosions, indolent erosions or ulcers, canine recurrent erosions, recurrent epithelial erosions, persistent corneal erosions, refractory corneal ulcers, nonhealing erosions, and idiopathic persistent corneal erosions. All of these refer to chronic erosions that fail to resolve through normal epithelial wound 23

24 healing. They are often caused initially by superficial trauma. Left untreated or if improperly treated, these erosions can persist for weeks to months. These erosions usually occur in middle-aged dogs and in all breeds of dogs, although boxers and retrievers are often overrepresented. Another subset of dogs that often have indolent ulcers are older and may have underlying pathology such as corneal edema. Clinical appearance superficial, non-infected erosion surrounded by a sheet of non-adherent epithelium the epithelium may appear thickened fluorescein stain often leaks beneath the abnormal, loose epithelium resulting in a less intense ring of staining around the exposed stroma usually axial or paraxial degree of neovascularization varies tremendously varying degrees of blepharospasm Pathogenesis The loss of the basement membrane is significant, as it results in longer epithelial wound healing time and may imply an adhesion complex abnormality, since normal basement membrane is not easily removed with superficial trauma. The presence of fibronectin on the surface of the erosion suggests that early epithelial wound healing is occurring, but that reformation of adhesion complexes is delayed, leading to recurrent removal of the poorly attached epithelium. Distinct stromal changes (i.e., abnormal nerve plexus, superficial stromal hyalinized zone) that develop under SCCEDs imply that stromal abnormalities are a crucial part of the pathophysiology of this disease. Matrix metalloproteinase (MMP) 2 and MMP 9 are more likely related to chronicity rather than the specific pathophysiology. Medical treatments Oxytetracycline: Corneal ulcers were treated via debridement and grid keratotomy. Dogs were assigned to receive 1 of 3 treatment regimens for up to 6 weeks. Over two weeks 74% healed with topical oxytetracycline ointment, 50% with oral doxycycline and triple antibiotic and 10% with oral cephalexin and triple antibiotic. Tetracyclines have been shown to inhibit matrix metalloproteinases (MMPs) and have anti-poptotic and anti-inflammatory effects. Topically applied polysulfated glycosaminoglycans (PSGAGs) have been reported to result in an 82% healing rate. This therapy is thought to work by decreasing proteolytic activity; however, a related study found increased proteolytic activity in the tears of only a portion of effected dogs, indicating that PSGAGs may only be helpful for a subset of effected dogs. Serum is often recommended for treating corneal ulcers in animals because it contains fibronectin, but given that studies have shown that fibronectin is already present at the site 24

25 of SCCEDs, it is not clear what role the administration of topical fibronectin may play in their treatment. Cross-linked hyaluronan (Remend) may accelerate resolution of corneal ulcers and may encourage a more normal epithelial architecture. There have been no published studies on its effects on indolent ulcers. Surgical treatments: Epithelial debridement has long been a mainstay of therapy. After application of a topical anesthetic, dry, sterile, cotton-tipped applicators are used to gently remove the loose epithelium, starting in the center of the erosion and working outward in a radial pattern. Normal corneal epithelium is very firmly attached to the underlying stroma and is not easily removed with a cotton-tipped applicator, so debridement is continued until all loose epithelium is removed (without fear of unnecessary removal of normal epithelium). Often, a much larger area of epithelium is removed than originally indicated by fluorescein staining. Success rates for debridement alone are quite variable between studies, but combining the outcomes in these studies results in an overall success rate of approximately 50%. Punctate or grid keratotomy involves making either small punctures or linear scratches in the superficial stroma, which likely creates channels for epithelial cells to penetrate the abnormal superficial stromal hyalinized zone. Anterior stromal puncture increases extracellular proteins such as collagen IV, laminin, and fibronectin that are important in epithelial adhesion and are often absent in SCCED lesions. To perform a grid keratotomy, small lines are made in a crosshatched pattern with a 25 or 22 g needle with the bevel up held tangentially to the cornea extending from normal cornea across the epithelial defect. To perform an anterior stromal puncture, a 25-gauge needle is clamped in a hemostat so that the tip of the needle is barely exposed. This allows the hemostat to be used as a handle and controls the depth of the puncture. After application of topical anesthesia and debridement of loose epithelium, multiple small punctures are made 0.5 to 1 mm apart across the surface of the exposed stroma and extending 1 mm into the normal, surrounding attached epithelium. Success rates between studies vary, ranging from 68% to 88% with a multiple punctate keratotomy and 87% with a grid keratotomy. Combining the outcomes in these studies results in a success rate of approximately 80%. A contact lens or third eyelid flap may also be used after these procedures; one study found that 100% (12/12) of eyes healed after treatment with grid keratotomy followed by a third eyelid flap. Diamond burr debridement is done after topical anesthetic is applied and the epithelium is debrided with cotton tipped applicators. Diamond burr debridement is done using a battery-powered, handheld motorized burr. An abstract describing this technique reports that these cases heal faster than a grid, but does not give data. Another study placed a contact lens post-debridement. The results were good at 70% were healed at 7 days, 92% at 25

26 15 days and all were healed by the final recheck at about 19 days. A second DBD/BCL was performed in 5/40 (12.5%) of cases. The BCL retention rate was 95% over all examination time points. The only complication observed was one case of suspected bacterial keratitis post-dbd/bcl. Superficial keratectomy is almost 100% effective but requires general anesthesia and often an operating microscope or at least good magnification. Indolent ulcers are seen much less frequently in cats than in dogs. The same pathogenesis of decreased hemidesmosome formation by the epithelial layer is suspected. However, therapy recommendations differ for the cat. A recent paper showed that epithelial debridement is efficacious and increases the rate of healing. However, in contrast to dogs, the authors found that grid keratotomy not only lengthened the time to healing but also may increase the chances of developing sequestra. CALCIFIC KERATOPATHY Calcific keratopathy is a disorder of the cornea characterized by deposition of mineral (usually calcium). Corneal calcification generally appears as short spicules of a whitish, chalky looking material in the superficial corneal stroma. May be primary disease in geriatric dogs. Treatment Nothing if minor accumulation If becomes severe, try treatment with topical EDTA in artificial tears to chelate the calcium as it can lead to descemetocele formation. Response is variable. Conjunctival graft if deep ulcer or descemetocele forms PANNUS (or chronic superficial keratitis) An often bilateral immune mediated vascularized, pigmented lesion of the cornea. Begins as a red vascularized conjunctival lesion. Initially invades the temporal or inferior temporal limbus. A similar lesion often involves the leading edge of the 3 rd eyelid. Vascularization and pigmentation then invades the central cornea. Eventually it is a fleshy lesion that may involve the entire cornea, causing blindness. The etiology is probably multifactorial, incorporating immunemediated, genetic, and UV radiation. German shepherds are predisposed although it can occur in any breed. This disease is controllable but not curable. Diagnostics Appearance, signalment. Cytology will reveal lymphocytes and plasma cells. Treatment Begin treatment with topical dexamethasone or prednisone TID to QID then taper down to a controlling dose. It may take 3-4 weeks to get response. Cyclosporine or tacrolimus can also be used especially for maintenance. Very rarely can a pannus dog go off therapy completely. Most of these dogs can go down to once daily or once every other day dex or CsA or tacrolimus to stay in remission. Vascularization is used to monitor whether the lesion is quiescent or active. 26

27 Radiation can be used in severe cases. HERPETIC KERATITIS Etiology Feline herpesvirus 1 Herpetic keratitis can be caused by two mechanisms. The first and most common mechanism is cellular destruction of the corneal epithelium by the virus, which leaves a superficial ulcer which is usually linear or dendritic and can coalesce to form larger more typical appearing geographic ulcers. FHV-1 can also cause stromal damage when antigen builds up in the stroma do to a weak local immune response. Eventually when the immune system begins to react, the white blood cells attack the antigen in the stroma and keratitis ensues. Generally, these cats are painful with blepharospasm and have a serous to mucopurulent discharge. Pathology Primary infection is caused by viral replication in the epithelium of the upper respiratory tract and conjunctiva and less so in the corneal epithelium. The herpes virus is transmitted via respiratory and ocular secretions. Clinical signs occur secondary to the cytopathic effects in the infected tissue. Secondary bacterial infection may prolong signs. The virus can then ascend the sensory neurons and establish latency in the trigeminal ganglia. 90% of cats are seropositive, 80% of infected cats become latently infected and 45% will recrudesce with clinical signs or asymptomatic shedding. Stress, other illnesses and the use of corticosteroids may trigger recrudescence. Vaccination does not prevent infection but it reduces the severity of primary disease and decreases the load of virus in the ganglion. Clinical signs Acute conjunctival and upper respiratory infection in a neonatal or adolescent cat. Sneezing and ocular discharge are usually present. If uncomplicated, this clinical course lasts days. Serous discharge becomes mucopurulent, and conjunctival hyperemia develops, but usually not severe chemosis. Older cats may get the conjunctivitis without other respiratory signs if they successfully fought off the illness and conjunctivitis as a kitten. Often dendritic ulcers or geographic ulcers appear. Dendritic ulcers are linear and shaped like lightning bolts and are pathognomonic for herpes. The dendritic ulcers may not be positive on fluorescein staining unless the full thickness of the epithelium is absent. When herpes is suspected, staining with rose bengal may delineate a dendritic ulcer in which the epithelial cells are dead but have not sloughed. Dendritic ulcers may coalesce and form larger geographic ulcers. Often corneal vascularization and scarring occurs, but pigmentary changes do not develop. Frequently cats have a decreased STT. Stromal keratitis is diagnosed when the corneal edema is greater than that expected with a superficial ulcer, deep corneal vessels are appearing, and cellular infiltrate is present. 27

28 Diagnosis Made based on clinical signs. With primary infections the clinical signs tend to be characteristic and self-limiting. In the chronic stages the clinical signs are subtle and less characteristic, and there is less viral shedding so laboratory diagnostics are not as easy to interpret. Additionally, many cats are normal and shed virus. The easy cases to diagnose are those with dendritic ulcers as they are pathognomonic. A history of URT disease in cat with keratitis or any chronic ulceration in cats should raise suspicion of herpes. Fluorescent antibody testing of conjunctival scrapings may be done; however, it is not very sensitive and prior fluorescein staining can give false positives. Polymerase chain reaction (PCR) is very sensitive and specific, but it may be too specific and locate viral particles in the tissue from previous infections. Differential diagnoses for cats with conjunctivitis are chlamydia, mycoplasma and calicivirus. All of these cause conjunctivitis but not corneal ulceration. Treatment: There are many topical antiviral drugs. The 2 most commonly used topical drugs are cidofovir and trifluorothymidine and both are virostatic. Cidofovir (0.5%) is administered twice daily. Trifluorothymidine should be given 6-8 times for the first 2 days then QID for a week after clinical signs have resolved. Response to the antiviral drugs is usually good, but treatment can be frustrating. Famcyclovir is an oral medication given at 90 mg/kg BID. It has been shown to decrease clinical signs. Lysine competes with arginine in viral DNA thereby interfering with viral replication. Studies vary in their results but lysine may decrease clinical signs and/or decrease viral shedding. It can be used indefinitely (if effective) to reduce the frequency of recurrences. The suggested dose is 500 mg orally BID. Topical antibiotics (oxytetracycline, Terramycin ) - Primarily indicated if ulcers are present. Oxytetracyline is broad spectrum and is effective against other causes of conjunctivitis in cats. Mydriatic /cycloplegics: topical atropine ointment. Use to effect if an ulcer is present to decrease pain associated with ciliary body muscle spasm. Artificial tear ointments, especially Genteal Severe Eye, seems to be very soothing. Treating herpes stromal keratitis can be very complicated. Treatment with antiviral drugs is initiated for 2-3 weeks. If there is no response or a minimal response, then topical steroids such as dexamethasone or prednisone is added to the treatment. Usually after a couple weeks there will be great improvement. Then discontinue the steroids and continue the antiviral drugs for 1 week past resolution of signs. This is the only condition in which steroids are used in the treatment of herpes. 28

29 FELINE CORNEAL SEQUESTRUM Corneal sequestration is a keratopathy unique to the cat. It has been described in most breeds of cats, but occurs most often in brachycephalic cats such as Persians and Himalayans. Young adult cats are most commonly affected. Usually the disease is unilateral but is bilateral in about 20% of cats. Most corneal sequestra occur following corneal ulceration or chronic irritation. The predisposition of this disease in certain breeds suggests that there may be a primary stromal or epithelial dystrophy. The breeds that are most commonly affected with this condition have prominent eyes. This prominence may increase the susceptibility to corneal irritation, trauma, lagophthalmos and premature evaporation of the tear film. Some ophthalmologists associate herpes virus with the sequestra. Clinical findings Feline corneal sequestra have the characteristic appearance of a brown to black, central or paracentral round plaque in the cornea. Clinically sequestra may protrude from the corneal surface, or involve any depth of the stroma. Usually there is concurrent superficial corneal vascularization. Other common concurrent ocular clinical signs are ocular discharge, conjunctival hyperemia, blepharospasm, entropion, chemosis, epiphora, corneal edema, and protrusion of the third eyelid. Therapeutic goals To decrease pain, eliminate the lagophthalmos and infection, and decrease the severity of the keratitis. Sequestra might slough spontaneously but may take months to years to do so. Topical use of antibiotics and corticosteroids alone seems to have no effect on the course of the disease. Lamellar keratectomy with a corneoconjunctival transposition or conjunctival graft is the preferred therapy for eyes that are painful with sequestra. A lamellar keratectomy can be safely performed to 1/2 the depth of the corneal stroma. When a keratectomy extends deeper than 1/3 to1/2 of the stromal thickness, a corneoconjunctival transposition or conjunctival graft should be used to minimize pain from an uncovered keratectomy site and to physically support the thinned stroma. Additionally, the recurrence rate is much lower when a graft has been placed than after keratectomy alone. Conjunctival grafts are technically easier to do than corneoconjunctival transpositions. Corneoconjunctival transpositions may result in less scarring than conjunctival grafts; however, the conjunctiva in cats is so thin that the difference in vision after the two surgeries is probably not different. Now some cases only receive a collagen graft after the keratectomy. EOSINOPHILIC KERATITIS Eosinophilic keratitis is a proliferative disease of the superficial cornea of cats. Initially there is corneal vascularization of the temporal or nasal limbal cornea. The lesion then develops into a proliferative white/pink irregular vascularized mass. There may be corneal vessels and edema peripherally. Often a white/yellow granular film will be present on the surface of the lesion. 29

30 Eosinophilic keratitis may be unilateral or bilateral. Occasionally the conjunctiva and nictitans may be affected as well. Additionally, some cats may have concurrent corneal ulceration. Cats show signs of discomfort inconsistently. Eosinophilic keratitis usually affects young adult domestic short hair cats, but other breeds also develop the disease. There has been no association of this disease with the dermatologic disease, eosinophilic granuloma complex. The etiology is unknown. Diagnosis Based on appearance and cytologic findings. Cytology of corneal scrapings reveals eosinophils, mast cells, lymphocytes and neutrophils and is diagnostic. Histologic appearance is a chronic granulomatous response with a leukocyte infiltrate of plasma cells, lymphocytes, eosinophils and mast cells. Because the appearance and cytology are so characteristic, histology is rarely indicated. Treatment 0.1% dexamethasone or 1.0% prednisolone acetate ophthalmic drops are used 4 times daily initially. Taper slowly as improvement occurs. The lesions are considered resolved when the plaques and corneal vessels have receded. Some use megesterol acetate, but it can cause serious side effects such as diabetes mellitus, endometritis and polyuria and polydipsia. This is NOT recommended. With refractory cases, I have needed to resort to short-term adjunctive therapy with oral prednisone or topical cyclosporine. Recurrences often occur especially with cessation of treatment; the mean time to recurrence in one study was 10 months. When ulcers are present concurrently, the ulcer should be treated with topical antibiotics and atropine ointment until resolved prior to initiating steroid therapy. 30

31 Releasing the Kraken: A Fear Free Experience Kathryn Primm, DVM 2018 UTCVM Distinguished Coughlin Visiting Professor Introduction: Kathryn Primm, the Nation s first Fear Free Certified professional. People go into veterinary medicine because they love animals. When animals panic at the sight of vet professionals, it hurts everyone. Fear Free is a protocol that can help. The Fear Free mission is to alleviate fear, anxiety and stress in pets and educate and inspire the people that care for them. The Program- Level 1 Module 1: Fear Free Behavior Modification Basics Module 2: Fear Free Transport of Cats and Dogs to and from the Veterinary Hospital Module 3: Fear Free Reception and Waiting Area Module 4: The Fear Free Exam Room Module 5: Fear Free In-Hospital Care Module 6: Fear Free Procedures Module 7a: Pre-visit Protocols: Complementary Therapeutics, Products, and Pharmaceuticals Module 7b: In-Hospital Protocols for Sedation, Anesthesia, and Analgesia Module 8a Leadership, strategic planning and metrics Module 8b Human resources and operations Module 8c Marketing your Fear Free certification There are other benefits to being certified including: Online Community As of April 2017: 11,000+ individuals have registered for the program 4,500+ individuals have completed the program and are Fear Free certified 31

32 ~150 new professionals register, and an average of 100 professionals become certified each week 95% would recommend the program to other veterinary professionals. Releasing the Kraken :A Fear Free experience Have you ever thought that your patients are like Andromeda, the girl who is being sacrificed? In fact, most of your patients are Which of your patients could benefit from Fear Free protocols? Science tells us that most of our patients are suffering from some degree of fear, anxiety and stress. The truth about fear is that fear is never unlearned. It is stored in a separate part of the brain than the other memories. As someone who has pledged to care about Andromeda (our patients), shouldn t we try to make this experience better for her? We need to realize that this is a pervasive mindset that it is normal or even funny for pets to be afraid of the vet. We do not have look very far to find someone joking about it. There are so many photos on the internet that have been shared ridiculously. What Happens When Animals Suddenly Realize They Are at the Vet It is our responsibility to make owners think about what they are communicating to pets. It all comes down to how we explain the fears. We can build an image for your client that makes the pet s feelings easier to understand and raise awareness. Teach owners what to look for to know when the pet is stressed. Once you have raised their awareness, they will notice the signs because of their Selective Attention. New information is the easiest to remember. After you have been exposed to something new, you pay more attention to it. The DOG ABCs of FAS A- Avoiding Eye Contact B-Barking, Biting C- Clinging to owner, Cowering D- Dilated pupils, dribbling urine E- Ears lowered F- furrowed brow, freezing G- growling 32

33 H- Hiding, Hypervigilance J- jumping up L-Licking lips, lifting a paw, lip curling M- mouth tight P- Panting, pacing R-Restless S-Shaking, Shedding, staring T- tail tucked, trembling, turning away W-whale eye, wont take treats Y- yawning The CAT ABCs of FAS A- Avoiding Eye Contact B- Biting C- Cowering D- Dilated pupils E- Ears flat F- freezing G- growling H- Hiding, Hissing L-Licking R-restless S- Shedding/ shaking T-tail tucked/trembling 33

34 We will examine photos and videos to assess FAS in the featured pets. You can use what you have learned on any patient! Client Education Now teach your clients. Make clients and staff aware of how tuned in pets are Think about what your patients perceive. Staff Other pets Vet Tools of the Trade Is restraint adding to panic? Feeling afraid is made worse when you have no escape route. It escalates the fear to life/death panic instinctively. Is sound adding to the fear? Sound can be used as a weapon or device of torture, yet we allow frightening sounds in our facilities every day. What does she smell? Have you ever thought about what pets smell? We will talk about what and how pets perceive molecules and what they must think about them. Our noses are supposed to warn us of danger and it is even more remarkable for pets. What about temperature? Pets experience ambient temperatures differently than we do. Many of our surfaces are cold and slick. Warmth has been scientifically proven to give a sense of safety and feelings of trust. Perception is reality for animals Think about you & your hospital. Are you inadvertently telling your patients that the Kraken is going to eat them? Take home messages All of your patients have some degree of FAS whether you see it or not Fear is a cascade that is never unlearned Your clients probably don t see it and if they do, they think it is ok 34

35 If you raise client awareness, they will be on your team Think of all the senses when you look at your hospital experience Which Kraken do you want to be? 35

36 Everybody Benefits from Fear Free SM Kathryn Primm, DVM 2018 UTCVM Distinguished Coughlin Visiting Professor Veterinary Professionals and Clients Epic Fail We will look at a video of the handling of a frightened and defensive patient and talk about it in detail. The video is disturbing and illustrative of why we need to change. Dexter is one of my only patients that I have not had a complete success with. Veterinary Oath Being admitted to the profession of veterinary medicine, I solemnly swear to use my scientific knowledge and skills for the benefit of society through the protection of animal health and welfare, the prevention and relief of animal suffering, the conservation of animal resources, the promotion of public health, and the advancement of medical knowledge. I will practice my profession conscientiously, with dignity, and in keeping with the principles of veterinary medical ethics. I accept as a lifelong obligation the continual improvement of my professional knowledge and competence. What is the result of this for us? Job dissatisfaction Unhappiness Feeling unappreciated Leaving the profession Guilt Shame Suicide What about veterinary staff? There is a known shortage of qualified veterinary staff. 22% of credentialed technicians are not employed as of the date of the survey (NAVTA) Almost ½ of those have left the industry. They cite compassion fatigue, burnout, feeling unappreciated, being underpaid as the reasons for departing the industry. We have an obligation to make this better for our own! It is likely that these numbers are falsely 36

37 decreased. The respondents were those reached out to by NAVTA and there are many staff members that were not surveyed. Veterinarians are feeling the strain too 6.8 % of males and 10.9 % of females in the profession have serious psychological distress compared with 3.5 % and 4.4 % of U.S. male and female adults % of males and 36.7 % of females in veterinary medicine have experienced depressive episodes since veterinary school, which is about 1 1/2 times the prevalence in U.S. adults overall throughout their lifetime % of males and 19.1 % of females who are veterinarians have considered suicide since graduation. This is three times the U.S. national mean. 1.1 % of males and 1.4 % of females in the veterinary profession have attempted suicide since veterinary school. Fear Free protocols help accentuate the positive, eliminate the negative. Fear Free allows us to: give best care which is why we are here Reduces stress and compassion fatigue which we named as a reason for career unrest Increases owner compliance because owners feel like they are not hurting the pet Restores our reputation as those who care the most which gives us back some the respect that we miss What about the pet owners? In the clip of the cat earlier, in the first few seconds, there is a girl s voice and she says, I am afraid. She later says that she is going to stay away and Taz, you are scaring me. The experience was not only horrible for the patient and the staff. It was traumatic for the owners too. People do not care how much you know, until they know how much you care. Studies show us that the decrease in veterinary visits is not because pet owners do not care about their pets. In fact, most reported that they think of their pets as members of their family. The decrease in veterinary visits is much more likely to due to the fact that pets hate to come and see us! Fear Free can help you fix it. We all must acknowledge that profit is an underlying goal of practice. 37

38 Mathematical Formula for Success of a Vet Practice Who are the people through your door? The people entering your business fall into two categories New Clients Existing Clients Where do NEW clients come from? 1. Location 2. Internet 3. Word of mouth How can Fear Free help me get new clients? A REFRESHING change! We BECOME the news. Open the toolbox. **People believe that animals are good judges of character. How can Fear Free help get existing clients back in the door? Owners want to see the pet happy (maybe even more than healthy) They want to feel that you to care about the health AND welfare of the pet Fear Free can remove barriers to seeking care Mathematical Formula for Success of a Vet Practice Following recommendations: Doing more at a visit I don t want to put her through that If you do have to sedate the pet, it is an easy sell to explain that you could do everything that he needs and he will not even know it Part of the burden falls on you Less stress is better medicine Your diagnostics will more truly reflect the pet s state. 38

39 You will be able to perform more complete work up of cases with a calm and happy pet. I lost a GOOD client (at least one that I know of)over painful injections and a stressful visit. If we consider the value of a single pet over its life span is very high, my loss of a client who had 5 pets was significant. Everyone wins with Fear Free. You can see dogs dragging owners TO your door. Pets get better care because owners are more proactive about bringing them. That s better medicine with improved client retention and a decrease in lapsed visits.and you FEEL good! After almost 21 years of practice, I had lost some of my passion and fervor, but I always loved my patients. I love them and now, they love me! 39

40 Implementation: How in the world can I make this work? Kathryn Primm, DVM 2018 UTCVM Distinguished Coughlin Visiting Professor It may seem unlikely, but it can happen! You know why, but how? You have been exposed to the theory and implementation of Fear Free principles The Fear Free Certification program will teach you all that you need to know to implement. We will explore a video tour of my own clinic before implementation of Fear Free. What did we do wrong? Now think about your clinic. What could you change easily? Could you add better and more treats? What about ditching the lab coat? Could you talk with owner about the signs of stress that seemed already present in the parking lot? Place a warm mat on the scale? Are Fear, Anxiety, and Stress (FAS) Always Present? FAS occurs along a continuum from barely stressed at all, to severely stressed with compromised well-being and safety of all involved Review of body language The best way to know a patient s emotional state and whether she is relaxed enough to cope with the stress of veterinary procedures is to watch her body language Our behavior and body language affects the patient s emotional state When the veterinary team is relaxed and calm, the patient is more likely to be relaxed and calm, too Review of Dog Body Postures Review of Cat Body Postures 40

41 Considerate Approach Considerate approach (CA) encompasses the interaction between the veterinary team and the patient and inputs from the environment when veterinary care is being administered Smell of fear -Clean up anal glands and wipe down all scopes! Pheromone sprays and diffusers Warmth and texture Warm fluffy pastel bath mats & towels everywhere Is restraint adding to the panic on an instinct level? Try stabilizing with gentle control Video case examples. Touch Gradient Touch gradient is a term used to describe how to touch our canine and feline patients to minimize Fear, Anxiety and Stress (FAS) during veterinary procedures Touch gradient has two components: initiating hands on physical contact with a patient, and administering treatments that involve contact with the body such as injections, nail trimming etc. The Touch gradient begins by maintaining continual physical hands on contact throughout the entire procedure or examination whenever possible Sporadically touching our patients can result in a startle response which may lead to FAS Touch gradient includes acclimating a patient to an increasing level of touch intensity associated with veterinary procedures, while continuously measuring the patient s acceptance and comfort Recruiting others Staff training- a series of staff meetings, select videos from the module to my staff The secret to team work I ve Got Your Back 41

42 When my staff knew how to explain the strategies, they also knew that they could get me and I would support exactly what they had said because it s a published protocol Stopping point rules- 3 seconds or 3 struggles for dogs, 2 seconds or 2 struggles for cats Define your stopping point and don t waver. Be passionate and let the passion spread Treats are the mainstay Everything is better with bacon Bacon (TINY pieces) Peanut butter Easy Cheese Commercial treats Things I have learned that are not in the program No Stethoscope around my neck Odds and ends No can in my hand. Spray cheese in a can is a no go for many of my nervous dogs. (Cats do not seem to care) Dogs know what wrappers and bowls are. We use plastic bags and sealable bowls when we can. Cats are said to love green olives. Sardine paste is supposed to be a good cat option Ask owners if there is a special treat that their pet loves Trick or Treat Try engaging the owner even more. Ask if their dog can do tricks. Don t forget that cats can do tricks too! It is NOT ok to hurt me If a procedure or even an exam is expected to be painful, draw the line Use items from your tool box. Posters on the wall stating that we will not hurt or force Handouts, s explaining 42

43 Screen Savers There are templates that will be included in the Fear Free toolbox moving forward Don t wait to medicate. My favorite drugs We will talk about the medications that I use everyday and how to decide which are the most appropriate for each case. What if I can t get down? We have an extra chair in our exam rooms. Sometimes I sit on the chair next to the owner and have the patient on their lap or mine.many clinics have installed benches, especially for cats so that the cat can settle next to the owner Low cost TIPS Distraction-vaccines are fairly easy to distract from. Choose low volume vaccines for pet comfort Use small and new needles. This adds minimal cost Understand that you may need extra time and additional staff, but once you get a flow, this is less of an issue Find the currency for that pet: food, tricks, attention or if he would just prefer to miss the experience completely with pharmaceuticals. Window perch. Be ready to perform exams and injections on the perch or in the carrier. Don t push past the point of fear. Do you really need to force his mouth open or can you can gain enough info with a gentle lip lift? Need versus Want Ear temp/rectal temp Close exam of teeth, ears and mouth? Comprehensive invasive type exams under sedation Train Educate Distract Medicate 43

44 WHICH ANTIBIOTIC, WHEN AND FOR HOW LONG? Jane Sykes BVSc(Hons) PhD DACVIM Professor of Small Animal Internal Medicine University of California, Davis, CA, USA INTRODUCTION In recent years, there has been a frightening rise in the prevalence of multidrug resistant bacteria in dogs and cats. Because of this, whenever possible veterinarians should make attempts to confirm a suspected bacterial infection by requesting microscopic evaluation of direct smears, culture and susceptibility by a laboratory before the choice is made to administer an antimicrobial drug. A Gram stain prepared from the specimen can permit the rapid preliminary diagnosis of infection, and provide information regarding whether the organism(s) present are gram-positive or gramnegative. This helps guide the clinician to select an appropriate empiric therapy, if necessary, while awaiting the results of culture and susceptibility testing. Important terms used to describe resistant bacterial infections are as follows: Beta lactam: antimicrobial drug that includes a beta-lactam ring (all penicillins, cephalosporins and carbapenems such as meropenem). These bind to penicillin binding proteins (PBPs) (bacterial enzymes that catalyze bacterial cell wall formation) and cause bacterial lysis. Beta lactamases: bacterial enzymes that destroy the beta lactam ring (associated with resistance to beta-lactams). These include a variety of penicillinases. Beta lactamase inhibitors are drugs that inhibit these enzymes and include clavulanic acid and sulbactam. ESBLs: extended spectrum beta lactamases. These are bacterial enzymes that destroy critical beta-lactam drugs needed for treatment of resistant bacterial infections in humans (by definition, third generation cephalosporins such as cefuroxime, cefotaxime, ceftazidime). They are generally expressed by gramnegative enteric bacteria such as E. coli and Klebsiella. MRS: methicillin resistant staphylococcus. These organisms express an altered penicillin binding protein (PBP2a) that does not bind beta-lactam drugs. Therefore they are resistant to penicillins, cephalosporins and carpapenems. MDR: multidrug resistance. By definition, this is resistance to 3 or more CLASSES of antimicrobial drugs (e.g., cephalosporins, fluoroquinolones, and aminoglycosides). METHODS OF SUSCEPTIBILITY TESTING Clinical microbiology laboratories will perform susceptibility testing for most aerobic bacteria, with the exception of streptococci. Streptococci from dogs and cats are almost always susceptible to penicillins. Most laboratories also do not routinely perform susceptibility testing on anaerobes, which also mostly have predictable susceptibilities, although resistance in anaerobes is increasing and some anaerobes, such as Bacteroides fragilis, have a high prevalence of β-lactamase enzyme production. Susceptibility testing can be performed using dilution methods or diffusion methods. The minimum inhibitory concentration (MIC) is the lowest concentration of 44

45 antimicrobial drug that inhibits visible growth of an organism over a defined incubation period, most commonly 18 to 24 hours, and is determined using dilution methods, which involve exposing the organism to 2-fold dilutions of an antimicrobial drug. The concentration range used varies with the drug and the organism being tested. Standard protocols are published by the Clinical and Laboratory Standards Institute (CLSI) that specify medium composition and ph, inoculum size (determined on the basis of turbidity measurements), inoculation procedures, agar depth and incubation conditions, as well as quality control requirements. Because failure to comply with these protocols can lead to erroneous results, veterinarians should always attempt to use laboratories that follow CLSI or EUCAST protocols. The most widely used dilution method is broth microdilution, whereby 2-fold dilutions of antimicrobials are made in a broth media in a microtiter plate. Pre-prepared frozen or freeze-dried plates are available commercially for inoculation (e.g., SensititreÒ plates, TREK Diagnostic Systems). The results can be determined using visual examination of the plates for the inhibition of bacterial growth, or by the use of semiautomated or automated instrumentation. The MIC for each antimicrobial drug tested against the organism is reported to the clinician on the susceptibility panel. It is the lowest concentration of antibiotic (usually in µg/ml) that inhibits growth of the organism in vitro, and the lower the MIC, the more potent the antimicrobial is at inhibiting bacterial growth. Diffusion methods include gradient diffusion (also known as Etest ) and disk diffusion. The Etest involves use of a plastic strip coated with an antimicrobial gradient on one side and an MIC interpretive scale on the other side. An agar plate is inoculated with the organism of interest so that subsequent growth of the organism will form a lawn, rather than individual colonies. The strips are applied to the surface of the plate, with the lowest concentration towards the center. The antimicrobial drug diffuses into the medium, which results in an elliptical zone of growth inhibition around the strip. The MIC is read at the point of intersection of the ellipse with the MIC scale on the strip. Although the strips are expensive, Etests have the advantage of being adaptable to use with fastidious organisms and anaerobes if susceptibility testing of these organisms is deemed necessary. Disk diffusion involves application of commercially available drugimpregnated filter paper disks to the surface of an agar plate that has been inoculated to confluence with the organism of interest, and is also known as Kirby-Bauer antibiotic testing. Commercially available, mechanical disk-dispensing devices can be used to apply several disks simultaneously to the surface of the agar. The drug diffuses radially through the agar, the concentration of the drug decreasing logarithmically as the distance from the disk increases. This results in a circular zone of growth inhibition around the disk, the diameter of which is inversely proportional to the MIC. The zone diameters are interpreted on the basis of guidelines published by CLSI and the organisms are reported as susceptible, intermediate or resistant. BREAKPOINTS AND DEFINITION OF SUSCEPTIBLE VS. RESISTANT ORGANISMS Once susceptibility testing has been performed, organisms are classified on the susceptibility panel report as susceptible (S), resistant (R), and, in some cases, of intermediate (I) susceptibility. This refers to a predicted in vivo situation, rather than in 45

46 vitro susceptibility. The growth of susceptible isolates should be inhibited by concentrations of antimicrobial agent that are usually achievable in blood and tissues using normal dosage regimens. "Intermediate" isolates have MICs that approach usually attainable blood and tissue levels and for which response rates may be lower than those for susceptible isolates. This category implies clinical efficacy in body sites where the drugs are normally concentrated (e.g., enrofloxacin and amoxicillin in urine) or when a higher-than-normal dose of a drug can be used, and acts as a buffer zone in order to prevent technical factors from causing major discrepancies in interpretations. Resistant isolates should continue to grow in the face of the usually achievable concentrations of the drug in blood and tissues. In order to determine if an in vivo response is likely, the laboratory refers to breakpoints, or clinical cut-off MICs (or, for disk diffusion testing, cut-off zone diameters), which are established, published, and revised regularly by committees associated with standards agencies such as the CLSI. If the MIC determined in the microbiology laboratory is lower than the published breakpoint, then the organism is defined as susceptible. The breakpoint is not reported to the clinician. Breakpoints are established on the basis of multiple factors, which include 1) a knowledge of MIC distributions and resistance mechanisms for each organism-drug combination, 2) clinical response rates in humans and animal models, 3) how the drug is distributed and metabolized in the body (pharmacokinetics), and 4) whether the drug is concentrationdependent or time-dependent as it relates to antibacterial effect (pharmacodynamics). Zone diameter breakpoints for disk diffusion testing are determined by correlation with MIC values. For simplicity, breakpoints are established for bloodstream infections, and are based on a specific dosage regime for the antimicrobial drug tested, which are selected by the standards agency involved. Because some antimicrobials are concentrated extensively in urine, some veterinary laboratories may report urine MIC panels, which provide breakpoints for lower urinary tract infections, which are higher than corresponding serum MIC breakpoints. These have been controversial because the possibility of concurrent pyelonephritis cannot always be ruled out. Breakpoints are often re-evaluated when new mechanisms of resistance appear in bacteria or when new data are generated that improve understanding of the pharmacokinetics and pharmacodynamics of an antimicrobial drug. THE CLINICIAN S ROLE IN INTERPRETATION OF SUSCEPTIBILITY PANELS The veterinary clinician should always remember that the list of drugs reported in the susceptibility panel is simply just a list of drugs tested. They are not suggestions from the laboratory for patient care. The clinician should always ask 4 main questions, in order, when faced with a susceptibility panel: 1. Is this organism that was cultured likely to be the cause of disease? (i.e., should I treat this organism?) Once a positive culture has been obtained, the veterinarian must consider the significance of the positive test result, even if susceptibility test results are reported. The detection of bacterial organisms within a sample does not always imply that the organism is causing the animal s clinical signs. Contamination is the most common 46

47 cause of false positive cultures. Isolation of only one or two colonies of coagulasenegative staphylococci, Bacillus spp., Corynebacterium spp., and propionibacteria commonly suggest contamination. Isolation of large numbers of a single type of bacteria from a normally sterile site is generally clinically significant, especially when supported by cytologic examination of a stained smear that demonstrates the presence of bacteria within leukocytes. 2. Are any of the drugs shown as susceptible the appropriate drugs for treatment of the bacterial species cultured? Laboratories often (but not always) report results for specific antimicrobials on the basis of the organism being tested (e.g., cephalosporins may not be reported for enterococci because of intrinsic resistance). Certain antimicrobials should be generally be reserved for treatment of multiple-drug resistant organisms that cause lifethreatening infections (e.g., vancomycin, linezolid, meropenem). 3. Assuming the drugs are active against the bacterial species isolated, are the drugs the right drugs for the patient in question? a. Will they achieve adequate concentrations at the site of infection? b. What route of administration is necessary and can the antimicrobials be administered by the route that is most appropriate for my patient? c. Could adverse drug reactions occur in this patient with these antimicrobials? d. Could drug interactions occur in this patient with these antimicrobials? For infections in sites such as the CNS, the clinician needs to consider whether or not an antimicrobial to which the organism is reported as susceptible will penetrate that site. The clinician should also consider other factors, such as immunosuppression, pregnancy and other concurrent illness or drug therapy, when treating infections on the basis of antimicrobial susceptibility test results. 4. Is the antimicrobial drug currently being administered the most appropriate for the infection I am trying to treat? Because antimicrobial susceptibility testing results are generally not available until 2-3 days after submission of a specimen for culture, in animals that are critically ill, antimicrobial therapy may already have been initiated by the time those results are available. The susceptibility results may show that the organism is resistant to a drug being used, in which case the drug should be changed to one that the organism is susceptible to. The susceptibility pattern can also aid in choosing an alternate drug when the patient does not tolerate the initial drug prescribed. Susceptibility testing may indicate that the organism is susceptible to a more narrow-spectrum (and generally less expensive) antimicrobial drug than the drug initially prescribed, in which case the treatment should be changed to minimize the development of antimicrobial resistance. 5. Can I shorten the duration of therapy? Currently there is a trend to try to shorten the duration of therapy to minimize selection pressure on bacterial populations. This differs from previous recommendations to 'finish a course' of antimicrobial drugs. In general, surgical prophylaxis should involve 47

48 administration of antimicrobials only in the immediate peri-operative period (immediately before and during surgery). GUIDELINES FOR ANTIMICROBIAL USE The International Society for Companion Animal Infectious Diseases (ISCAID) Antimicrobial Guidelines Working Group was formed to develop guidelines for antimicrobial drug use in dogs and cats, because of concerns that antimicrobial drug resistance has dramatically increased in prevalence among isolates from dogs and cats in the last decade. The founding members of the ISCAID Working Group are Scott Weese, Joseph Blondeau, Dawn Boothe, Edward Breitschwerdt, Luca Guardabassi, Andrew Hillier, Michael Lappin, David Lloyd, Mark Papich, Shelley Rankin, Jane Sykes, and John Turnidge. Input has also been obtained from panels of Diplomates of relevant specialty groups. It should be noted that members of the working group receive support from a variety of industry groups that provide funding for honoraria and research. Guidelines for treatment of urinary tract disease in dogs and cats, respiratory disease and superficial pyoderma have been published and are available as open access documents for any individual to download ( During the course of guideline development, it became clear that there is a significant lack of objective, published information. Accordingly, recommendations are based on available data, whenever present, along with expert opinion, considering principles of infectious diseases, antimicrobial treatment, antimicrobial resistance, pharmacology, and internal medicine. Clinical trials that evaluate antimicrobial drug regimes for bacterial infections in dogs and cats are encouraged. Because of the increased prevalence of antimicrobial drug resistance, the need to properly document the presence of an infection before initiating antimicrobial drug treatment is more important than ever. In veterinary medicine, this may be at odds with client financial resources. However, inappropriate use of antimicrobial drugs is wasteful of client resources when an infection is not present or a multidrug resistant pathogen is present, and risks selection for antimicrobial resistant bacteria that may be harmful to the pet, other animals, and also humans that are in contact with the animal. Clinicians should choose laboratories for culture and susceptibility (C&S) testing that follow protocols and use breakpoints published by the Clinical and Laboratory Standards Institute (CLSI), EUCAST or other internationally recognized institutions. The Working Group hopes that veterinarians will re-think the empiric use of antimicrobial drugs, especially when the underlying condition is not immediately life-threatening. An emphasis on rational antimicrobial treatment needs to be made to pet owners. A selection of the basic recommendations within the urinary, respiratory and superficial pyoderma guidelines are summarized below. Doses of specific antimicrobial drugs are listed in the guidelines. 1-3 In general, as the guidelines have evolved, there has been an emphasis on shortening the duration of antimicrobial therapy. The information below does not represent the final recommendations of the Working Group, but provides an update for practitioners on the current perspective of the author as part of the Guidelines Working Group. RECOMMENDATIONS FOR URINARY TRACT DISEASE Sporadic Cystitis 48

49 Definition: Sporadic bacterial infection of the bladder in an otherwise healthy individual with normal urinary tract anatomy and function. A clinically significant infection implies the presence of dysuria, pollakiuria, and/or stranguria. Complete urinalysis should be performed for all cases and quantitative aerobic C&S testing is encouraged. Free-catch samples should be avoided. Recommendations for initial treatment are amoxicillin (11 15 mg/kg PO q12h) or trimethoprim-sulfonamide (15 mg/kg PO q12h). If culture and susceptibility (C&S) testing reveals a resistant isolate and there is a lack of clinical response, treatment should be changed to an appropriate antimicrobial drug. Although treatment has been recommended in the past for 7 to 14 days, recent research suggests 3-5 days may be more appropriate. There is no evidence that intra- or post-treatment urinalysis or urine culture is indicated in the absence of ongoing clinical signs of UTI. Recurrent Bacterial UTI Definition: Recurrent UTIs are defined by the presence of 3 or more episodes of UTI during a 12-month period or 2 or more infections within a 6-month period. Efforts should be made to identify the underlying cause; consider referral Treatment should be based on the results of C&S testing, with initial empiric therapy following the recommendations for Sporadic Bacterial Cystitis Although 4 weeks has been recommended for treatment, shorter durations are likely to be recommended in the future, with a focus on clinical cure rather than microbiological cure. There is insufficient evidence to recommend pulse or chronic low-dose treatment, urinary antiseptics, and nutritional supplements such as cranberry juice extract for prevention of UTIs. Subclinical Bacteriuria Definition: presence of bacteria in the urine as determined by positive bacterial culture, in the absence of clinical signs of UTI. Treatment may not be necessary, but could be considered if there is a high risk of ascending or systemic infection (eg. patients with renal disease). Urinary Catheters Proper aseptic placement and maintenance is critical. Open collection systems should not be used. If clinical signs of lower UTI or pyelonephritis are absent, then no culture or treatment is indicated. The duration of catheterization should be as short as possible. Catheter removal is not necessary in the presence of subclinical bacteriuria. There is no indication for routine use of prophylactic antimicrobials after the catheter is removed. If clinical signs of a UTI or fever are present, then perform a culture after replacement of the urinary catheter with a new catheter. Several milliliters of urine should be removed to clear the catheter before a specimen is obtained for culture. Alternatively, the catheter can be removed and a cystocentesis performed. Culture from the collection bag, and culture of the catheter tip after removal are not recommended. Treatment should follow the guidelines for sporadic bacterial cystitis, and is more likely to be successful after catheter removal. Pyelonephritis C&S testing should always be performed. Treatment should be initiated while awaiting culture results, using antimicrobials effective against Gram-negative Enterobacteriaceae. A fluoroquinolone is a reasonable first choice, after which treatment should be based on C&S results. If combination treatment was used initially and C&S results indicate that both drugs are 49

50 not required, the spectrum should be narrowed. Treatment for 4 weeks has been recommended, but it is likely that shorter durations of treatment (10-14 days) may be effective. Culture is recommended 1-2 weeks after treatment is discontinued, together with a physical examination and assessment of azotemia, but the possibility of subclinical bacteriuria should be considered when interpreting culture results. Medical dissolution of struvite urolithiasis Urine culture should be performed in all cases where urolithiasis is identified. Culture of surgically-removed uroliths can be considered, but the clinical relevance of results is unclear. If evidence of bacterial cystitis is present, antimicrobial drug selection should be approached as per sporadic cystitis. Seven days of treatment is recommended for animals with urolithiasis and concurrent bacterial cystitis. The need for further treatment is unclear. Urine culture after completion of medical urolith dissolution is not recommended in the absence of clinical signs of lower urinary tract disease. Confirmation of elimination of uroliths through diagnostic imaging and investigation of predisposing factors for cystitis (and subsequent struvite urolith risk) is important. Bacterial prostatitis Empirical treatment should target Enterobacteriaceae. Administration of a veterinary fluoroquinolone such as enrofloxacin should be considered while awaiting culture and susceptibility testing results. Use of trimethoprim-sulfonamide can be considered but is not recommended where a fluoroquinolone can be used because of the greater risk of adverse effects with the typical duration of treatment. Limited data are available to guide duration of treatment. Four weeks is typically recommended for acute prostatitis, with 4-6 weeks for chronic disease. Shorter durations might be effective in acute cases that are castrated and where there is quick clinical response. A longer duration of treatment may be required in some chronic cases, particularly when abscessation is present or when castration is not performed. Castration should be recommended in dogs that are not intended for breeding. Poor initial response to therapy should lead to re-assessment of the diagnosis and if prostatitis is still suspected, consideration of collection of ultrasound-guided fine needle aspirate of prostatic cyst fluid or prostatic tissue core biopsy for culture and cytology or histopathology. Prostatic abscesses should be drained because of the low likelihood of resolution with medical treatment alone. If necessary, surgical drainage should be performed after culture results are available, whenever possible, to facilitate proper peri-operative antimicrobial therapy. RECOMMENDATIONS FOR SUPERFICIAL PYODERMA The cause of most superficial bacterial folliculitis (SBF) in dogs is Staphylococcus pseudintermedius. Methicillin-resistant S. pseudintermedius (MRSP), which is often highly multi-resistant, has now spread rapidly throughout the world. This has focused attention on the need to ensure that diagnosis and treatment of SBF is managed in an optimal way so as to resist the spread of this organism. SBF only occurs when there is an underlying problem such as allergic dermatoses, hyperadrenocorticism, hypothyroidism, or demodicosis. These need to be differentiated from SBF. 50

51 Diagnosis of SBF should be supported by cytological examination and the demonstration of coccoid bacteria associated with inflammatory cells and within phagocytes. Cytology is also important for identification of co-infection with Malassezia pachydermatis. SBF must be distinguished from other causes of folliculitis and pustular disease. It should be differentiated from demodicosis by deep skin scrapings and from dermatophytosis by fungal culture. Culture is essential if there is a poor response to 2 weeks of appropriate systemic antimicrobial therapy, emergence of new lesions 2 weeks or more after the initiation of such therapy, presence of residual lesions after 6 weeks of therapy combined with cytology demonstrating infection with cocci, when cytology reveals intracellular bacterial rods, and when there has been a history of a multidrug resistant infection in the dog or a dog that shares the household. C&S testing is encouraged in cases of recurrent SBF infection or when there has been a history of treatment with antimicrobial drugs. Specimens for culture should be taken from pustules. If pustules are not found specimens may be taken from pus beneath crusts, and from papules or epidermal collarettes. Contact with owners should be maintained to promote effective compliance and to determine if and when failure to respond to treatment, or recurrence, occurs. Topical antimicrobials (ointments, gels and creams) should be considered, which can be applied to localised lesions 2 to 3 times daily. Such products may contain antibiotics (e.g., mupirocin), silver sulfadiazine, benzoyl peroxide and hydroxyl acids. More extensive areas of infection can be treated with shampoos, lotions, sprays and rinses. These contain antiseptics such as chlorhexidine, benzoyl peroxide, ethyl lactate, povidone iodine, triclosan and hydroxyl acids; they are commonly used 2 to 3 times weekly and until 7 days after lesions resolve, with contact times of 10 minutes before rinsing or conditioners. They can then be used for prophylaxis on a weekly or less frequent basis depending on response. Empirical systemic drug therapy choices can be made in non-recurrent cases and when there has been no history of antimicrobial drug exposure. Otherwise, drug selection should be based on C&S tests. First-tier empirical drugs include clindamycin, first generation cephalosporins, potentiated sulphonamides, and lincomycin. When firsttier drugs are not appropriate and topical therapy cannot be used, second tier drugs may be chosen; these include fluoroquinolones, doxycycline, chloramphenicol and rifampin. Most of the Working Group members felt that third generations cephaloporins should be second tier drugs, but the evidence to support their placement in this category was lacking, and so they were listed as first or second tier drugs. Systemic antimicrobial drugs given at subtherapeutic doses or as pulse therapy have been used to prevent or delay recurrence but such protocols are likely to promote the development of antimicrobial resistance and are discouraged. GUIDELINES FOR TREATMENT OF RESPIRATORY DISEASE Acute Upper Respiratory Tract Disease (URTD) Consider an observation period of up to 10 days without antimicrobial treatment for cats and dogs with acute URTD. Antimicrobial therapy should be considered if a 51

52 mucopurulent nasal discharge is accompanied by fever, lethargy or anorexia. In the latter case, appropriate empiric therapy would be doxycycline (first choice) followed by amoxicillin (the latter is not active against Mycoplasma spp.). The duration should be 7-10 days. Avoid performing culture and susceptibility (C&S) on nasal discharge from cats with acute URTD, as it usually yields commensal bacteria or secondary invaders. If empiric antimicrobial therapy is ineffective, the need for a diagnostic work-up should be emphasized to the client. Chronic Upper Respiratory Tract Disease in Cats A diagnostic work-up is recommended for cats with chronic upper respiratory signs, including imaging of the nasal cavity and rhinoscopy. If treatable causes of nasal discharge are not identified, then nasal lavage or brushings could be submitted for C&S testing, and a nasal biopsy could be submitted for histopathology. Treatment should be based on these results. Should nasal discharge recur, the previously effective antimicrobial drug should be used for a minimum of 48 hours; if this is ineffective, then switching to a different class of antimicrobials should be considered, provided a diagnostic work-up to rule out other causes of nasal discharge (tumors, fungal infection, foreign bodies etc) has been performed. Chronic Upper Respiratory Tract Disease in Dogs A diagnostic work-up is recommended for dogs with chronic upper respiratory signs, including imaging of the nasal cavity and rhinoscopy. Almost all dogs with chronic upper respiratory tract disease have disorders that are not effectively treated with antibacterials alone, such as nasal neoplasia, foreign bodies, lymphoplasmacytic rhinitis, and sinonasal aspergillosis. Bacterial Bronchitis in Dogs and Cats Airway lavage with cytologic examination and C&S testing is usually indicated if bacterial bronchitis is suspected. Non-bacterial causes of bronchitis should always be considered. While awaiting results of the above tests, empiric treatment is recommended with doxycycline for 7 to 10 days. If this results in clinical improvement, treatment should be continued for 1 week past resolution of clinical signs. Pneumonia Antimicrobial therapy for pneumonia should be initiated as soon as possible and within 1-2 hours if signs of sepsis exist. Antimicrobial therapy should be parenteral while 52

53 patients with pneumonia are hospitalized. If there is no evidence of systemic sepsis, parenteral administration of a beta-lactam such as ampicillin is recommended for empiric therapy; if signs of sepsis are present, then a combination of a fluoroquinolone and a drug that targets gram-positive bacteria and anaerobes (e.g., ampicillin or clindamycin) is recommended pending the results of C&S if possible. Animals should be re-evaluated for possible discontinuation of antimicrobials no later than 10 to 14 days after starting treatment. Pyothorax Pyothorax should be treated with IV fluids and drainage of pus after placement of chest tubes. Surgical debridement may be required. Empiric antimicrobial therapy pending the results of C&S should be with a parenteral combination of a fluoroquinolone and a penicillin or clindamycin. It has been recommended that treatment continue for at least 3 weeks and ideally 4-6 weeks, but the optimum duration is unknown. Animals should be re-evaluated 10 to 14 days after starting treatment. References 1. Weese JS, Blondeau JM, Boothe D, Breitschwerdt EB, Guardabassi L, Hillier A, Lloyd DH, Papich MG, Rankin SC, Turnidge JD, Sykes JE. Antimicrobial Use Guidelines for treatment of urinary tract disease in dogs and cats: antimicrobial guidelines working group of the International Society for Companion Animal Infectious Diseases. Vet Med Int 2011; Epub Jun Hillier A, Lloyd DH, Weese JS, Blondeau JM, Boothe D, Breitschwerdt EB, Guardabassi L, Hillier A, Lloyd DH, Papich MG, Rankin SC, Turnidge JD, Sykes JE. Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases). Vet Dermatol 2014;25(3):163-e Lappin MR, Blondeau J, Boothe D, Breitschwerdt E, Guardabassi L, Lloyd D, Papich MG, Rankin SC, Sykes JE, Weese JS. Antimicrobial Use Guidelines for treatment of respiratory tract disease in dogs and cats: antimicrobial guidelines working group of the International Society for Companion Animal Infectious Diseases. J Vet Intern Med

54 LEPTOSPIROSIS UPDATE IN THE UNITED STATES Jane E. Sykes BVSc(Hons) PhD DACVIM University of California, Davis INTRODUCTION Leptospirosis is caused by infection with various serovars of Leptospira interrogans sensu lato. Organisms are transmitted by direct contact with infected urine, bite wounds or ingestion of infected tissues, or indirectly, through contact with infected water, soil, food or bedding. Survival of leptospires is promoted by stagnant warm water, a neutral or slightly alkaline ph, and temperatures between 0 and 25 C. The seasonality of the disease is variable depending on local climactic conditions, especially rainfall. In areas with year-round rainfall, the disease may occur throughout the year. There are over 200 pathogenic serovars, which are grouped into antigenicallyrelated serogroups. Serovars known to infect and cause disease in dogs include Canicola, Icterohaemorrhagiae, Grippotyphosa, Portlandvere, Copenhageni, Dadas, Pomona, Ballum, Bratislava, Autumnalis, Bataviae, Australis, and Hardjo. In addition, classification of leptospires is gradually moving from predominantly serovar-based classification to that based on genetic typing (genotype-based classification). Each serovar (and more accurately, each genotype) is adapted to a one or more mammalian host species (maintenance hosts). Other hosts act as incidental hosts. Disease in incidental hosts tends to be more severe and the duration of shedding is generally shorter. Maintenance hosts include dogs (Canicola); rats (Icterohaemorrhagiae); small wildlife mammalian species such as voles, skunks, and raccoons (Grippotyphosa); cattle and pigs (Pomona); pigs (Bratislava); cattle (Hardjo); and mice (Ballum). The prevalence of infection with a serovar/genotype in dogs depends on the degree of contact between the dog population and the maintenance host for that serovar/genotype. The most common serovars thought to infect dogs before the introduction of the Leptospira vaccines several decades ago were Icterohaemorrhagiae and Canicola. After the introduction of the bivalent bacterins containing these two serovars, in North America and Europe, there were decreasing reports of disease associated with seroconversion to Canicola and Icterohaemorrhagiae, and increasing reports of disease associated with seroconversion to serovars Pomona, Grippotyphosa, Autumnalis and Bratislava (in North America) and Sejroe, Australis and Grippotyphosa (in Europe). Vaccine pressure, increasing contact between dogs and certain wildlife reservoir hosts and increased testing have been suggested as reasons for this change. In truth, the actual serovars causing disease in dogs worldwide still remain poorly characterized because the disease is diagnosed by serology, and serologic test results are not predictive of the infecting serovar, but recent studies using culture and PCR have begun to shed more light on the true infecting serovars. Pathogenic leptospires penetrate abraded skin or mucus membranes and multiply rapidly in the bloodstream and tissues, causing renal failure, hepatic injury (usually not hepatic failure) and vasculitis. The disease is multisystemic and may also involve the pancreas (pancreatitis), gastrointestinal tract (gastroenteritis), eye (uveitis) and lungs (leptospiral pulmonary hemorrhage syndrome, or LPHS). In humans, 54

55 Leptospira can also cause meningitis, which is most commonly manifest as a severe headache. Clinical manifestations may also depend on the age of the host, the infectious dose, and the strain of Leptospira involved. CLINICAL MANIFESTATIONS Most infections are subclinical. Younger, large breed, outdoor adult dogs are commonly affected, but the disease can occur in any dog breed and at any age; dogs that live in cities may become infected as a result of exposure to rodent reservoir hosts. One study showed an increase in the percentage of small breed dogs diagnosed with leptospirosis between 1970 and 2009 (Lee et al, 2014). Younger animals tend to be more severely affected. Male dogs may be predisposed. Lethargy, anorexia, vomiting, pyrexia, dehydration, abdominal pain and increased thirst and urination are common signs of acute leptospirosis. Reluctance to move due to myositis, icterus, and uveitis may be noted. Respiratory difficulty may result from pulmonary hemorrhage, which is often associated with the development of moderate anemia. LABORATORY FINDINGS Leukocytosis, thrombocytopenia, azotemia, hypoalbuminemia and mild to moderately elevated liver enzyme activities are common. Although hyperkalemia has been reported, normokalemia or hypokalemia are more common because of the effect of Leptospira on the renal medullary thick ascending limb tubular Na+-K+-Clcotransporter. Urinalysis may reveal isosthenuria, proteinuria, glucosuria and casts. Although it occurs with other causes of renal tubular damage, glucosuria in addition to azotemia can be a red flag for a diagnosis of leptospirosis. Proteinuria is typically lowlevel (urine protein:creatinine ratio < 5), which helps differentiate leptospirosis (interstitial nephritis) from Lyme nephritis (which involves the glomerulus). Thoracic radiography may reveal a focal or diffuse interstitial to bronchointerstitial pattern; alveolar patterns may represent pulmonary hemorrhage. Occasionally mild pleural effusion is evident. Hepatomegaly, splenomegaly, renomegaly and/or peritoneal effusion may be evident from abdominal radiography. Hyperechoic renal cortices and mild renal pelvis dilation are occasionally seen with abdominal ultrasound. DIAGNOSIS Canine leptospirosis is an underdiagnosed disease in some regions/practices and an overdiagnosed disease in other regions/practices. Identification of leptospirosis requires a high clinical suspicion for the disease based on knowledge of the range of clinical presentations that suggest leptospirosis. Currently available diagnostic tests include PCR, serology using the microscopic agglutination test (MAT), and in-clinic serologic assays that detect IgG/IgM (SNAP Lepto, IDEXX Laboratories), or IgM (WITNESS Lepto, Zoetis). In the MAT, respective titers are provided for each of several different serovars in order to increase the chance of antibody detection. Studies in humans and dogs have shown that the serovar with the highest titer can vary over time and that paradoxical cross-reactivity to multiple serovars occurs after exposure to a single serovar. Thus, the MAT does not accurately predict the infecting serovar, and therefore should not be used 55

56 for this purpose. Titers with any serologic test may be negative in the first week of illness because of the short incubation period and delay in antibody production. Low positive or negative titers after at least one week of illness suggest leptospirosis is not present. Overdiagnosis results from misinterpretation of positive serologic test results. Positive titers early in the course of an illness may reflect residual post-vaccination titers or prior subclinical infection, and are not diagnostic for the disease. Demonstration of a fourfold rise in titer is required over a 1-2 week interval. In acutely ill dogs (< 1 week of illness), it is the author s opinion that leptospirosis serology should only be performed in a paired fashion or not at all, because of the limited utility of a single positive titer, regardless of its magnitude. Postvaccinal titers against Icterohaemorrhagiae, Canicola, Grippotyphosa and Pomona occasionally rise as high as 1:6400 for a few months after vaccination, and these can interfere with interpretation. The results can also vary dramatically between laboratories (Miller et al, 2011). Use of a laboratory with a high level of quality control is recommended, or a laboratory that participates in the International Leptospirosis Society s proficiency testing scheme. In-clinic serologic assays yield qualitative (positive or negative) results, and are useful for screening dogs for the presence or absence of antibodies. Should these kits yield negative results, then the clinician should consider whether it may be too early for the animal to have developed antibodies (as can occur with the MAT). Another test should be performed one week later to see if the animal seroconverts. The IDEXX assay detects IgG and IgM, and should these kits yield positive results, then the clinician should consider whether previous vaccination has occurred. Previous exposure without clinical disease should also be considered as a reason for positive results. The Zoetis assay detects IgM, and appears to be more sensitive than other assays early in the course of illness (Lizer et al, 2017a). Positive results may occur as a result of very recent vaccination or exposure; in one European study, 19/25 dogs were seronegative using the WITNESS Lepto by 12 weeks after vaccination (Lizer et al, 2017b). Clinicians should consider reflex testing with MAT in order to obtain a quantitative titer if positive results occur using in-clinic serologic tests, followed by convalescent serology 1-2 weeks later in order to document a change in titer. Additional clinical validation of these assays in different regions of the United States would be helpful to confirm their sensitivity and specificity. Darkfield microscopy of the urine is not recommended as sole test for diagnosis because of the large number of false positives and false negatives. Silver staining and fluorescent antibody or immunoperoxidase staining of tissue specimens can also yield false negatives, and do not help identify the infecting serovar. Culture is difficult because of the fastidious growth requirements of leptospires and the need for specialized media. The sensitivity of PCR assays is still not well established, and they do not provide information about the infecting serovar, although they have been used to provide information on genotype. The author s experience is that PCR may be insensitive for diagnosis of canine leptospirosis, but the sensitivity and specificity may vary geographically depending on the serovars present and shedding patterns that occur for those serovars. The sensitivity may also be higher very early in the course of illness and in dogs that have not received any treatment with antimicrobials. PCR assays are best performed on blood AND urine concurrently because urinary shedding begins 10 days after the onset of infection. 56

57 TREATMENT Specific treatment involves initial use of parenteral penicillin derivatives for leptospiremia. In the author s hospital, ampicillin is generally used (20 mg/kg IV q6-8h, adjusting dose down if severe azotemia is present) for up to 14 days or as long as the patient is vomiting or appears nauseated. It is recommended that treatment then be changed to doxycycline (5 mg/kg PO q12h) for 2 weeks, in order to eliminate the carrier phase. Doxycycline can be used instead of penicillins if vomiting does not occur after administration. Supportive therapy is also indicated for acute renal failure (eg. IV fluids, H2 blockers, antihypertensives, gastric protectants, antiemetics, phosphate binders, packed red cells and nutritional support). The use of hemodialysis can improve survival in dogs with severe renal failure. Approximately 50% of the patients with leptospirosis at the author s institution are dialyzed, and the average number of treatments required before polyuria and recovery occurs is 3. Euthanasia or death due to leptospirosis is recorded in 18% of our dogs. PREVENTION In North America, vaccines are available for serovars Canicola, Icterohaemorrhagiae, Pomona and Grippotyphosa and in widespread use. The vaccines are generally safe and efficacious and studies suggest they provide a 1-year duration of immunity (Minke et al, 2009; Klaasen et al, 2003). A recent study at our institution that examined over 130,000 dogs seen at a mobile vaccine clinic showed that although administration of a Leptospira vaccine increased the risk of adverse reactions, the risk of a reaction was still extremely low (0.45%, compared with 0.28% for all vaccines). Moreover, when broken down by type of adverse event, the rate of hypersensitivity-type events (most severe) increased from 7.2/10,000 dogs to 9.1/10,000 dogs with administration of Leptospira vaccine and this increase was not significant (Yao et al, 2015). Although it was prevalent when the two-way (Canicola and Icterohaemorrhagiae) vaccines were in widespread use, vaccine failure appears to be extremely rare with the current 4-serovar vaccines (Hennebelle et al, 2013). Leptospira bacterins have been associated with occasional acute, severe allergic reactions, but the incidence of these reactions has decreased dramatically in recent years, and reaction rates appear to be approaching those of distemper-hepatitis-parvovirus vaccines, even in small breed dogs. Vaccination against pathogenic leptospires is strongly recommended for dogs living in areas where leptospirosis occurs (ie. throughout the US), and are recommended even for small breed dogs that are confined to urban backyards, because of the possibility of infection as a result of rodent exposure. Minimizing access to rodents, farm animals and other wild animals also should help to prevent infection. PUBLIC HEALTH RISK Leptospirosis remains an important zoonosis, although most documented human leptospirosis in North America results from recreational activities that involve water, rather than contact with dogs. Because dogs are generally incidental hosts they may not shed for significant periods of time, although more studies are required to confirm this, and there are anecdotal reports of leptospirosis in staff that work in veterinary hospitals. 57

58 Human leptospirosis is typically a flu-like illness, but in some cases may be associated with vomiting, diarrhea, shock, jaundice, renal failure, pneumonia, meningitis, or abortion. Any animal with acute renal failure should be treated as a suspect. Warnings should be placed on cages, gloves should be worn while handling these dogs and bleach or iodine-based disinfectants should be used to clean areas soiled with urine. Owners should be warned that without specific treatment, leptospires may be shed in the urine for months despite clinical recovery. The ACVIM has published consensus guidelines for the diagnosis, treatment, and prevention of leptospirosis in dogs (Sykes et al, 2011). At the author's hospital, contact precautions are lifted after 72 hours of specific antimicrobial therapy. Selected References: 1. Miller MD, Annis KM, Lappin MR, et al. Variability in results of the microscopic agglutination test in dogs with clinical leptospirosis and dogs vaccinated against leptospirosis. J Vet Intern Med 2011;25(3): , 2. Minke JM, Bey R, Tronel JP, et al. Onset and duration of protective immunity against clinical disease and renal carriage in dogs provided by a bi-valent inactivated leptospirosis vaccine. Vet Microbiol 2009;137: Klaasen HL, Molkenboer MJ, Vrijenhoek MP, et al. Duration of immunity in dogs vaccinated against leptospirosis with a bivalent inactivated vaccine. Vet Microbiol 2003;95: Yao PJ, Stephenson N, Foley JE, et al. Incidence rates and risk factors for ownerreported adverse events following vaccination of dogs that did or did not receive a Leptospira vaccine. J Am Vet Med Assoc 2015;247: Hennebelle JH, Sykes JE, Carpenter TE, et al. Spatial and temporal patterns of Leptospira infection in dogs from northern California: 67 cases ( ). J Am Vet Med Assoc 2013;242: Sykes JE, Hartmann K, Lunn KF, et al ACVIM small animal consensus statement on leptospirosis: diagnosis, epidemiology, treatment and prevention. J Vet Intern Med 2011;25(1): Lee HS, Guptill L, Johnson AJ, Moore GE. Signalment changes in canine leptospirosis between 1970 and J Vet Intern Med 2014;28(2): Ball C, Dawson S, Williams N. Leptospira cases and vaccination habits within UK vet-visiting dogs. Vet Rec 2014;174(11): Lizer J, Velineni S, Weber A, et al. Evaluation of 3 serological tests for early detection of Leptospira-specific antibodies in experimentally-infected dogs. J Vet Intern Med 2017a; Nov 13 [Epub]. 10. Lizer J, Grahlmann M, Hapke H, et al. Evaluation of a rapid IgM detection test for diagnosis of acute leptospirosis in dogs. Vet Rec 2017b;180(21):

59 VECTOR-BORNE DISEASES Jane E. Sykes University of California, Davis Davis, CA, USA Infectious diseases that may be transmitted to dogs and cats by vectors include viral, bacterial, protozoal, and parasitic diseases. Some animals have positive serologic tests for vector-borne infections, but do not have active infection; this situation is more likely for acute infections such as Rocky Mountain Spotted Fever, borreliosis and granulocytic anaplasmosis. Examples of chronic persistent infections are bartonellosis, Babesia vogeli babesiosis, ehrlichiosis (especially caused by Ehrlichia canis and Ehrlichia ewingii), hepatozoonosis, and dirofilariasis. Cytauxzoon felis infections in cats and Francisella tularensis infections in dogs and cats can also be chronic. Babesia gibsoni infections and possibly also Babesia conradae infections are blood-borne and transmitted through aggressive interactions between animals or transplacentally transmitted, rather than as a result of vector-borne transmission. Hemoplasma infections may also be transmitted this way among cats. Some vector-borne infections have the potential to be transmitted to humans. Bartonella infections are of special concern because they are chronic and subclinical, so less likely to be suspected. They are also highly prevalent in kittens in shelters in regions where fleas are widespread. Precautions to prevent accidental exposure to blood and body fluids should reduce the risk that animal handlers may become exposed to these agents. Detailed discussion of all vector-borne infections is beyond the scope of this presentation, so the focus will be on Bartonella, Borrelia, Ehrlichia, Anaplasma, Babesia vogeli, and Hepatozoon infections, with an emphasis on treatment and prevention. Lyme Disease Borrelia burgdorferi is the cause of Lyme disease, the most common vector-borne disease in humans. Ecologic changes primarily farmland reforestation and residential development in wooded areas, an associated explosion in deer populations, and close proximity of reservoirs, ticks, humans, and dogs have all likely contributed to increasing recognition of Lyme disease. The tick vectors in the United States are Ixodes scapularis (upper midwest and northeast) and Ixodes pacificus (west). The primary mammalian reservoir in the upper midwest and northeast regions is Peromyscus leucopus, the white-footed mouse. Following inoculation of spirochetes into the host by the tick, the organisms migrate through connective tissue from the bite site, causing fever, inappetence, thrombocytopenia, and lameness due to neutrophilic polyarthritis in some dogs approximately 2 to 5 months after infection. As a result, seronegative Lyme disease is rare in dogs. A small percentage of dogs may develop glomerulonephritis (so-called Lyme nephritis). The vast majority of dogs show no signs of illness. In humans, B. burgdorferi causes erythema migrans, arthritis, and neurologic signs (neuroborreliosis). Dogs have been used as a sentinel for human exposure. A specific diagnosis is generally obtained through serology for antibodies. Diagnosis is often difficult, however, because of the widespread subclinical exposure in endemic areas. In dogs, diagnosis can involve detection of antibodies to the C6 peptide, which can be performed using the in-house SNAP 4Dx Plus kit (IDEXX Laboratories, Westbrook, ME) or the IDEXX quantitative C6 ELISA. Other assays, such as that offered by Antech, detect antibodies against 59

60 multiple Borrelia surface proteins. Polymerase chain reaction (PCR) assays are available as part of vector-borne disease PCR panels but have limited sensitivity when performed on blood because the organism resides primarily in connective tissues. Apparently healthy, seropositive dogs should probably be evaluated for proteinuria and co-infections with other tick-borne pathogens, and tick control should be recommended. Vaccination could also be considered to reduce the chance of reinfection. Although vaccination has not been shown to prevent Lyme nephritis, in theory this should be possible because the vaccines work within the tick, so that exposure to Borrelia does not occur. Generally, treatment of sick dogs involves administration of doxycycline for 4 weeks, but complete elimination of the spirochete may not occur. Dogs with Lyme nephritis are being treated with some success using immunosuppressive drugs. Granulocytic Anaplasmosis Anaplasma phagocytophilum is the cause of granulocytic anaplasmosis and is transmitted by the same Ixodes species that transmit Borrelia burgdorferi. A variety of species may be infected, including horses, ruminants, dogs, cats, and wildlife. The largest number of cases has been seen in the upper midwest and northeastern United States, and the disease is increasingly reported from other areas, including northern California, southwestern Oregon, the northwest coast, and Vancouver Island in British Columbia. Clinical signs of granulocytic anaplasmosis include fever, lethargy, inappetence, peripheral lymphadenopathy, and lameness due to neutrophilic polyarthritis. Neurologic signs have been reported anecdotally but are rare. Laboratory abnormalities may include leukopenia, thrombocytopenia, and elevated alkaline phosphatase (ALP) activity and sometimes alanine aminotransferase (ALT) activity. Morulae may be seen occasionally on blood smears within granulocytes, most commonly neutrophils. Diagnosis is otherwise based on acute- and convalescent-phase serology using indirect immunofluorescent antibody (IFA) assay. Acute titers may be low or negative. Serologic panels such as the SNAP 4Dx Plus test kit and the Accuplex assay detect antibodies to Anaplasma species, which could result from recent or previous exposure. PCR assays are the author's preferred diagnostic test and are useful for diagnosis early in the course of illness, when antibodies have not had time to form. Treatment is with doxycycline for 2 weeks, which usually results in resolution of clinical signs. Whether persistence of this organism occurs in dogs is controversial, but one recent study found no evidence of persistence after 28 days of doxycycline therapy (Yancey et al, 2017). Bartonellosis Bartonella species include Bartonella henselae, Bartonella clarridgeiae and Bartonella vinsonii subspecies berkhoffii. These are curved, gram-negative bacteria that reside within erythrocytes and endothelial cells and the presence of fleas is essential for their transmission. They cause cat scratch disease in immunocompetent people, as well as endocarditis, vasculoproliferative diseases and neurologic conditions in the immunocompromised. It was recently estimated that outpatients are diagnosed with cat scratch disease each year in the United States, and 500 inpatients are hospitalized with the disease (Nelson et al, 2016 EID). There are two genotypes of B. henselae, genotype I and genotype II, and it has been suggested that genotype I may be more likely to be zoonotic than genotype II. 60

61 The prevalence of infection of cats with B. henselae in endemic areas may be as high as 30% and is most often subclinical; in one 2015 San Francisco shelter study, the prevalence of bacteremia in kittens was 26% and the prevalence in young adult cats was 41% (Fleishman et al, 2015). Bartonella henselae was isolated most frequently, followed by B. clarridgeiae. The seroprevalence in kittens was only 10%, and it was 46% in young adult cats, emphasizing the fact that cats may be bacteremic but seronegative. Kittens were almost 5 times as likely to have a higher bacterial load than young adult cats, and they were twice as likely to be infected with genotype I than young adult cats. Most cats with bartonellosis have chronic subclinical infections. Endocarditis has been reported rarely in cats in association with Bartonella infection, and the organism is suspected to play a role in uveitis, lymphadenomegaly, gingivostomatitis, and possibly lower urinary tract disease in some cats, although the role of Bartonella in these syndromes has been controversial because of the high prevalence of infection in apparently healthy cats. In dogs, infection with Bartonella is of much lower seroprevalence (generally <5%) and has been associated most commonly with endocarditis. The prognosis for Bartonella endocarditis is poor when compared with that due to other bacterial pathogens. Diagnosis is generally made using serology, PCR and/or culture. Culture is useful in cats but has low sensitivity in dogs, which tend to have lower organism loads. Treatment of cats and dogs with subclinical Bartonella infections is not recommended, as Bartonella infection is difficult to eliminate using antimicrobial therapy, antimicrobial resistance may be increased, and handlers may become infected as a result of scratches inflicted during administration of medication. Doxycycline and azithromycin have been the most common antibiotics used to treat animals with clinical bartonellosis. However, resistance to azithromycin has been documented. 6 Ehrlichiosis Ehrlichioses of dogs are a group of tick-transmitted diseases caused by intracellular, gram-negative, bacteria that include Ehrlichia canis and Ehrlichia ewingii. Ehrlichia canis infects monocytes and causes canine monocytic ehrlichiosis (CME). Ehrlichia ewingii is an unculturable bacterium that infects granulocytes and causes canine granulocytic ehrlichiosis in the mid-western and southeastern United States. The geographic distribution of each pathogen is generally restricted to that of their vectors and mammalian reservoir hosts. Canine monocytic ehrlichiosis is most prevalent in the southernmost states. E. canis is transmitted primarily by Rhipicephalus sanguineus. Because of chronic, subclinical infection that can persist for month to years, dogs can be transported to non-endemic regions and subsequently develop disease years later. Ticks acquire infection by feeding as larvae or nymphs on infected dogs. The course of CME is divided into acute, subclinical and chronic phases, although these phases may not be clearly distinguishable. Clinical signs of acute CME occur 8 to 20 days after infection. Lethargy, inappetence, fever and weight loss are the most common signs. Replication of the organism in reticuloendothelial tissues is associated with generalized lymphadenopathy and splenomegaly. Ocular and nasal discharges, peripheral edema and less commonly, mucosal and cutaneous hemorrhages may also occur. Neurologic signs may occur. Dogs can recover within 2-4 weeks without treatment, after which they may eliminate the infection or remain subclinically infected. Chronic CME is typified by the finding of 61

62 pancytopenia, which results from hypoplasia of all bone marrow cells. Clinical signs include lethargy, inappetence, bleeding tendencies, mucosal pallor, fever, weight loss, lymphadenopathy, splenomegaly, dyspnea, anterior uveitis, retinal hemorrhage and detachment, polyuria/polydipsia, and edema. Secondary opportunistic infections such as viral papillomatosis can also develop, although the underlying mechanism of immunosuppression has not yet been elucidated. Protein-losing nephropathy may develop as a result of immunecomplex glomerulonephritis. E. canis DNA has been detected in some human patients with clinical signs of human monocytic ehrlichiosis, suggesting that E. canis may be a cause of monocytic ehrlichiosis in people. Thus, precautions should be taken when handling engorged ticks as well as blood and tissue specimens from infected dogs. Ehrlichia ewingii is transmitted by Amblyomma americanum ticks. Infection has been primarily identified in the south-central and southeastern parts of the United States. It causes fever, anorexia, lethargy and polyarthritis in dogs, as well as widespread subclinical infection. Rarely, it can cause disease in humans. There is evidence that E. ewingii may cause chronic persistent infections in dogs (Starkey et al, 2015). Diagnosis of Ehrlichia infections can be made based on visualization of morulae within circulating leukocytes, but this is insensitive, especially in dogs with chronic infections. More often, a diagnosis of previous exposure is made using in-clinic serologic tests that detect antibodies to Ehrlichia canis or Ehrlichia ewingii antigens. Diagnosis of active infection can be made using PCR on whole blood. Dogs with chronic E. canis infection frequently have extremely high IFA titers, sometimes > 1:600,000. An increase in titers over time (4-fold rise) does not generally occur in dogs with chronic disease, although antibody titers may decline in some dogs with treatment. The sensitivity of PCR for diagnosis of CME when performed on bone marrow in dogs with chronic ehrlichiosis appears to be less than 70% when compared with serology. The treatment of choice for Ehrlichia infections is doxycycline (10 mg/kg PO q24h) for a minimum of 28 days. Minocycline (10 mg/kg PO q12h) may also be effective for treatment of Ehrlichia canis infections (Jenkins et al, 2017). Most dogs with acute disease show clinical improvement within 24 to 48 hours. Dogs with severe chronic monocytic ehrlichiosis may not respond to therapy, or cytopenias may gradually resolve over a period of several months. Treatment of seroreactive, but otherwise apparently healthy dogs is controversial, because treatment has not been shown to change the outcome for these dogs and has the potential to lead to antimicrobial resistance or adverse effects of drug therapy. Babesiosis Babesia vogeli is the most significant vector-borne Babesia in the United States. It is transmitted by Rhipicephalus sanguineus, and primarily infects dogs (and especially greyhounds) in the southern United States. It has low virulence but can cause anemia and thrombocytopenia in puppies and splenectomized dogs. Diagnosis is most accurately achieved using species-specific PCR assays. Serologic assays that detect antibodies are available but positive results may reflect previous exposure and recovery rather than active infection. Treatment is with imidocarb dipropionate. 62

63 Hepatozoonosis In the United States, hepatozoonosis in dogs may be caused by Hepatozoon americanum and Hepatozoon canis, which are transmitted to dogs when they ingest infected Amblyomma maculatum (Gulf coast) ticks (H. americanum) or Rhipicephalus sanguineus ticks (H. canis), and probably infected paratenic hosts (predation). Infections have primarily been documented in the south-central, southern, and southeastern (VA) states in dogs with a history of roaming or predation. H. americanum is more pathogenic than H. canis and causes fever, lethargy, weight loss, lameness, muscle wasting, hyperesthesia, and often marked leukocytosis. Platelet counts are often elevated as well. Severe infections with H. canis may be associated with fever and lethargy. When gamonts are not seen in leukocytes on blood smears, diagnosis can be made using PCR assays on whole blood or muscle biopsy. Rocky Mountain Spotted Fever Rickettsia rickettsii is the cause of Rocky Mountain spotted fever. This is an acute disease of humans and dogs that is transmitted by Dermacentor ticks and occurs primarily in the southeastern United States, but transmission by Rhipicephalus sanguineus ticks has also been recognized in Arizona. Infection of endothelial cells results in a systemic vasculitis, which can be associated with severe edema, tissue necrosis, and often neurologic signs. Diagnosis is based on the result of acute- and convalescent-phase serology and/or direct fluorescence antibody on affected tissues. Cross-reactions can occur to nonpathogenic spotted fever group rickettsiae, and this must be kept in mind when interpreting the results of serology. PCR assays are also available, but sensitivity may be highest when performed on skin biopsy specimens rather than blood because of the organisms location within endothelial cells. Treatment is with doxycycline for at least 7 days. Mortality in humans may be as high as 10%, and dogs are important sentinels for human exposure. Plague and Tularemia Plague and tularemia are caused by Yersinia pestis and Francisella tularensis, respectively. Although uncommon, these diseases are important because they are highly infectious to humans and can be fatal. Plague occurs in the southwestern United States and is transmitted to cats and, to a lesser extent, dogs by rodent fleas. Tularemia occurs throughout the United States and is transmitted by ticks, especially Dermacentor species. F. tularensis is maintained in a variety of rodents and rabbits, and infection of cats and dogs usually occurs when they ingest these species. Clinical signs in cats and dogs include fever, lethargy, inappetence, lymphadenopathy, and subcutaneous abscesses. Most human infections result from exposure to infected arthropods or wildlife reservoir hosts, but when companion animals are involved in transmission, cats, rather than dogs, are most often implicated. Transmission of Y. pestis from cats to humans occurs as a result of bites, scratches, or respiratory droplet inhalation from cats with pneumonic plague. Dogs and cats have also exposed humans through the carriage of infected fleas into the household. When transmission of F. tularensis occurs from companion animals to humans, it generally follows cat bites. widespread vasculitis. 63

64 Cytauxzoon felis Infection Cytauxzoon felis is a protozoan parasite that is transmitted to cats by Amblyomma americanum ticks; bobcats are chronically and subclinically infected reservoir hosts. Cats with cytauxzoonosis can develop shock due to obstruction of venules with schizont-laden monocytes, followed by a severe, non-regenerative anemia that coincides with the appearance of piroplasms on blood smears. The treatment of choice is a combination of atovaquone and azithromycin. Hemoplasmas Hemotropic mycoplasmas, or hemoplasmas, are uncultivable, epierythrocytic Gramnegative bacteria that can cause red blood cell extravascular lysis and anemia in cats, dogs, and a variety of other animal species. Diagnosis of hemoplasma infections is based on visualization of coccoid bacteria associated with erythrocytes on blood smears, and/or the results of specific PCR assays. In recent years, several new hemoplasma species have been discovered in dogs and cats. Recent research has helped to determine the prevalence and clinical significance of each hemoplasma species worldwide. Mycoplasma haemocanis (Mhc) predominantly causes hemolytic anemia in splenectomized dogs, and rarely in dogs with other immunosuppressive disease. The organism forms rods, rings, and cocci, and characteristically, the cocci are often found in long chains. The prevalence of this infection appears to be particularly high in kennel-raised dogs. Over the last few years, two additional hemoplasma species have been detected in dogs. The first, Candidatus Mycoplasma haematoparvum (Mhp), was detected in a splenectomized dog with hemic neoplasia. We and others have also detected Mhm in several dogs using PCR. The clinical importance of these latter two organisms in dogs remains unclear. Rhipicephalus ticks have been suspected as a vector, but this has been questioned. Two hemoplasma species are prevalent in cats in the United States: Mycoplasma haemofelis (Mhf), and Candidatus Mycoplasma haemominutum (Mhm). Mhf is a larger ( µm) and more pathogenic organism that causes hemolytic anemia in immune competent cats. In contrast, Mhm is smaller and has not been clearly associated with disease in immune competent cats. Mhm is common in the feline population, infecting as many as 1 in 5 cats, whereas Mhf is found in < 3% of cats in most studies. A third feline hemoplasma has also been identified, Candidatus Mycoplasma turicensis (Mtc). Organism loads in cats infected with Mtc have typically been low, and light microscopic identification of Mtc has not been reported on blood smears from infected cats. A clear association between infection and disease has also not been made for this organism. The mode of transmission to cats for all of these organisms has been unknown. Fleas have been investigated as a vector but there is no strong evidence that they can transmit hemoplasmas to cats. Increasingly, biting has been accepted as the mod of transmission, and the strong male sex predeliction and association with FIV infection in our studies supports this mode. Transmission has occurred following blood transfusion, and prospective blood donors should be screened for hemoplasmas using PCR-based assays. Cytologic detection of hemoplasmas is considered to have very low sensitivity, and in some situations, low specificity. Mhf is visible less than 50% of the time in acutely infected cats, because organisms may disappear for several days before reappearing on blood smears 64

65 over the course of infection. Mhm and Mhp are extremely small, and Mhm is generally not visible in chronically infected cats. Mtc has never been seen on blood smears. When organisms are seen in cats, they are almost always Mhf. False positive diagnoses typically occur when staining artifacts such as stain precipitate are confused with organisms, although organisms also need to be distinguished from basophilic stippling and Howell-Jolly bodies. Several PCR-based assays have been developed for detection of hemoplasmas, including conventional and real-time PCR assays. It is important to consider the species detected in regards to whether they might be truly playing a role in disease. The treatment of choice for hemoplasmosis is doxycycline or pradofloxacin for a minimum of 2 weeks, and transfusion with packed red cells or whole blood where necessary. Pradofloxacin is the author s preference because of its improved safety profile over doxycycline in cats and efficacy against M. haemofelis. Marbofloxacin (2 mg/kg PO q24h) was shown to decrease Mhm copy numbers during therapy, but copy numbers increased to pretreatment levels on termination of therapy. Because of the potential for esophagitis, administration of doxycycline hyclate preparations should be followed by administration of a bolus of several milliliters of water. The use of immunosuppressive doses of glucocorticoids to suppress the associated immune-mediated hemolytic process is controversial, given the potential for glucocorticoids to cause reactivation of latent infection, but may be necessary in cats that fail to respond to antimicrobial therapy alone, or in cases where the diagnosis is uncertain. Treatment of Mhm infection is usually unsuccessful, and antimicrobial therapy cannot be used to reliably eliminate infection from potential blood donors. PREVENTION OF VECTOR-BORNE DISEASE TRANSMISSION Prevention of vector-borne infectious diseases in dogs and cats should involve searching for and removal of ticks after potential exposure, and year-round application of topical ectoparasiticides with activity against fleas and ticks. In recent years, there has been a dramatic expansion in the range of products available for prevention of flea and tick infestation, as well as a number of studies demonstrating decreased transmission of vector-borne infections in association with their use. The use of products with activity against fleas effectively prevents transmission of B. henselae. Products that contain S-methoprene, imidacloprid or pyriproxyfen are effective against all flea life stages, and products that contain permethrins generally kill and repel ticks. Most products are approved for puppies 12 weeks of age or older, but some have labels for use at as young as 6 weeks. Collars may lose activity or duration of activity with bathing. Traditionally, use of ectoparasiticides with activity against ticks in cats has been difficult because of cats' susceptibility to the adverse effects of amitraz and permethrin-based products. However, a flumethrin-containing collar (Seresto, Bayer Animal Health) and a fluralaner-containing topical ectoparasiticide (Bravecto for Cats, Merck) are now approved for tick and flea prevention in dogs and cats in the United States, which provide a solution to this problem. These products are especially useful in regions where Cytauxzoon felis is transmitted. Products labeled for cats that contain fipronil can also provide protection against ticks. Most topical and oral products start killing ticks and fleas within 8 hours. Additional products have recently become available in Europe, including a combination of 65

66 sarolaner and selamectin (Stronghold Plus, Zoetis) and a product containing a new isoxazoline, lotilaner (Credelio, Elanco). Pet owners should be educated about the reasons for application of ectoparasiticides, including prevention of zoonotic vector-borne diseases. They should also be told that while ectoparasiticides reduce the risk for vector-borne infections, they do not completely prevent these infections, especially in heavily infested environments. In the hospital environment, care should be taken to avoid direct contact with vectors found on animals during examination. Ticks should be removed with curved forceps or other tickremoval devices and disposed of in alcohol. When handling animals, care should be taken to avoid needlestick injuries and exposure to blood and even saliva. Because some infections can be transmitted through bites and scratches, staff should be educated on bite and scratch avoidance, such as the use of suitable restraint devices and protective gloves and warning signage on cages and records. All bites or scratches should be documented and consideration given to why the injury occurred, so that procedures or training to prevent future injuries can be implemented if necessary. 66

67 FRUSTRATING FUNGAL INFECTIONS: ADVANCES IN DIAGNOSIS AND TREATMENT Jane Sykes BVSc(Hons) PhD DACVIM Professor of Small Animal Internal Medicine University of California, Davis, CA, USA Introduction In recent years, fungal infections have been recognized more frequently in both human and veterinary patients, and the use of antifungal drugs has increased, especially with the use of more potent immunosuppressive drug treatments for longer periods of time. Efforts have focused on the development of new, less toxic and more efficacious antifungal drugs, and antifungal drugs with novel mechanisms of action, and early diagnosis for more effective treatment. The purpose of this presentation is to provide an update on new diagnostic tests for fungal infections, to review the use of some of the major antifungal drugs, and introduce some new human antifungal drugs with potential applications in veterinary medicine. Diagnosis of Fungal Infections Classically, dogs with deep mycotic infections are large breed, middle age to younger, male dogs. In North America, American Cocker Spaniels are predisposed to cryptococcosis, and German Shepherds and Rhodesian Ridgebacks to disseminated mold infections such as aspergillosis. However, infections can occur in dogs of any signalment, especially when there has been a history of immunosuppressive drug treatment. A history of travel to endemic areas may assist diagnosis in regions where the disease is not endemic. Although different fungal species vary in their organ tropism, fungal infections should be highly suspected in dogs with fever, nodular, cavitary, or lobar pulmonary lesions, osteolytic bone lesions, ocular inflammation such as uveitis or chorioretinitis, diskospondylitis, enlarged lymph nodes, or cutaneous nodules. Enlargement of the bridge of the nose or lesions of the planum nasale in cats should also raise suspicion for a fungal infection. In dogs, the nailbed is a site of predilection for many fungal infections. A lack of response to antibacterial drugs may also suggest underlying fungal disease. Rather than trialing multiple different antibacterials when an animal fails to respond to treatment, a diagnostic work-up should be initiated that includes appropriate tests for fungal infection. Major progress has been made in diagnostic testing for fungal disease in recent years. Cytology, histopathology and culture are useful but sometimes organisms are undetectable with cytology and histopathology, and culture may be dangerous to laboratory personnel. A history of antifungal drug use may render these assays falsely negative. In addition, these techniques may require invasive specimen collection techniques. Previously, with the exception of cryptococcosis, the only alternative tests available were assays that detect antibodies. These assays are largely only useful for diagnosis of coccidioidomycosis and nasal aspergillosis, provided they are performed and 67

68 interpreted correctly by the laboratory that performs the assays. A positive agar gel immunodiffusion assay titer in a dog suspected to have nasal aspergillosis is strongly suggestive of the disease, but a negative titer does not rule out the possibility of nasal aspergillosis. Commercially-available assays that detect antibodies to Histoplasma capsulatum and Blastomyces dermatitidis have also not shown to be useful for diagnosis, because of low sensitivity and specificity, but recent research suggests that alternative antibody assays for detection of Blastomyces infection may be more useful (Mourning et al, 2015). In the last few years, additional assays have become available that detect fungal antigens. These have been used extensively for diagnosis of disseminated mycoses in humans but have only recently been validated in dogs and cats. They are useful for diagnosis of histoplasmosis, blastomycosis, and systemic (not sinonasal) aspergillosis and are available in North America through MiraVista Diagnostics, Indianapolis, IN. Cross-reactivity between different fungal antigens can occur, especially between Blastomyces and Histoplasma antigens, and among mold pathogen antigens. Antigen tests for Blastomyces are most sensitive when used on urine rather than serum. For example, one study reported a sensitivity of 94% when the assay was used with urine and 87% with serum specimens. 1 Serial monitoring of urine Blastomyces antigen can also be useful to detect clinical remission and when there is suspicion for relapse, 2 although urine antigen can become negative when clinically detectable disease is present during treatment in some dogs, and clinical relapse can occur before urine antigen tests become positive. Preliminary studies on Histoplasma antigen testing in cats suggest that it is a sensitive test when performed on urine specimens. 3 In humans with histoplasmosis, the Infectious Diseases Society of America recommends monitoring urine antigen concentration during treatment and for at least 12 months after discontinuing treatment. 4 A rapid line immunoassay (IMMY) for cryptococcal antigen has recently become available and shows promise for in-practice diagnosis of cryptococcosis. Finally, PCR assays for detection of fungal pathogens are becoming increasingly available, but these will require validation in dogs and cats. A real-time PCR assay has recently been offered for detection of dermatophyte infections (Ringworm RealPCR, IDEXX Laboratories), but the clinical sensitivity and specificity of this assay requires further investigation and publication. Treatment of Fungal Infections Cure with antifungal drug treatment is most likely to be achieved in dogs with localized histoplasmosis, blastomycosis, and coccidioidomycosis, or in dogs with mold infections that have occurred secondary to immunosuppressive drug treatment and the immunosuppression can be reversed. Prognosis is poorest for dogs with disseminated mycoses that are predisposed breeds or that lack a clear underlying cause for their disease. The inflammatory response that follows organism lysis with treatment may lead to significant worsening of clinical signs in the first few days of treatment. Use of NSAIDs or, when the brain is involved, a short period of anti-inflammatory doses of glucocorticoids, may be required until the signs begin to resolve. 68

69 Some fungal infections respond to treatment with single agent fluconazole or itraconazole. The cost of fluconazole has reduced considerably, and recently a veterinary-labelled itraconazole solution (Itrafungol, Elanco) has appeared on the market for use to treat dermatophytosis in cats, that is somewhat less expensive than the equivalent human product (Sporonox). The two formulations should be bioequivalent. Itraconazole is often more effective than fluconazole, especially when bone lesions are present. Also, molds such as Aspergillus have intrinsic resistance to fluconazole so fluconazole should not be used to treat mold infections. Fluconazole penetrates the brain and the urinary tract, whereas itraconazole may not, unless significant inflammation is present. Practitioners are cautioned that many compounded formulations of fluconazole and itraconazole lack efficacy. When treatment failure occurs, serum drug levels can be performed to ensure adequate drug concentrations are present. Itraconazole levels should be performed at least 2 weeks after initiating treatment, because itraconazole can take this long to reach maximum serum concentrations. For dogs with disseminated disease, treatment with amphotericin B (AMB) should be considered, although this can be expensive, especially when lipid formulations are used. AMB irreversibly binds sterols in fungal cell membranes, forming pores with subsequent leakage of ions. AMB is virtually unabsorbed from the gastrointestinal tract, so it is formulated for IV infusion (FungizoneÒ, AMB-D) as a complex with the bile salt deoxycholate. Addition of electrolyte to the solution causes it to aggregate, so it is administered in D5W. Penetration of the CSF and vitreous humor is poor, but we have still had clinical successes using AMB intravenously for treatment of CNS infections. The major adverse effect of AMB-D is nephrotoxicity. Loading with IV 0.9% NaCl for 1 hour before the infusion decreases nephrotoxicity. Slow administration in a large volume of fluid also decreases nephrotoxicity. Fever, inappetence and vomiting also appear to occur in some dogs treated with AMB- D. Treatment with nonsteroidal anti-inflammatory drugs can be used to decrease pyrexia during therapy. Lipid Formulations of AMB Currently, three lipid formulations of AMB are marketed in the US. These are associated with a considerable reduction in nephrotoxicity compared with AMB- D. This allows administration of a higher dose of the drug, sometimes with improved treatment efficacy. Most experience in veterinary medicine has been reported with Abelcet, which is a mixture of AMB, dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol that forms ribbon-like sheets. Abelcet has been used in small animal patients to treat cryptococcal meningitis, disseminated coccidioidomycosis, blastomycosis, histoplasmosis, and pythiosis. Flucytosine (5-fluorocytosine) (cats only) Flucytosine has activity only against Cryptococcus neoformans and Candida spp. These fungi deaminate flucytosine to 5-fluorouracil, a potent antimetabolite. Drug resistance arising during therapy is very common, and so flucytosine must 69

70 ALWAYS be used in combination with other drugs. Penetration of the CSF is excellent and high urinary concentrations can be achieved. The most common adverse effects are myelosuppression and gastrointestinal upset. The drug should be avoided when renal failure is present. Administration of flucytosine should be avoided in dogs, as development of a severe (but reversible) drug eruption within 2-3 weeks of starting treatment is common. Unfortunately, flucytosine has recently become unaffordable for many pet owners. New Triazoles Newer triazoles are expensive and include voriconazole and posaconazole. Voriconazole is an excellent choice for treatment of refractory invasive mold infections in dogs. It penetrates the CNS, and uncommonly causes hallucinogenic-like neurologic signs in dogs. Cats are very predisposed to neurologic adverse effects and cardiac arrhythmias at the doses used in dogs and humans and so its use at those doses is contraindicated in cats. Recently, we completed a study that suggested that 12.5 mg/cat on an every third day basis has the potential to result in adequate serum concentrations in cats, although miosis is a potential adverse effect and drug accumulation over time might still occur. 5 Posaconazole is an itraconazole analog and has also shown efficacy for treatment of refractory fungal infections in dogs and cats. Absorption of the oral suspension has been shown to be variable in dogs, whereas use of the delayed-release tablet formulation has improved absorption and a longer half-life. A dose of 5 mg/kg q48h was suggested in that report for future studies. 6 Posaconazole suspension has also been used successfully to treat lifethreatening fungal infections in cats. The pharmacokinetics of posaconazole in cats has recently been reported (Mawby et al, 2016). Two treatment regimens using the oral suspension appeared to maintain targeted trough concentrations of μg/ml; either 30 mg/kg PO loading dose followed by 15 mg/kg q48h, or 15 mg/kg PO loading dose followed by 7.5 mg/kg q24h. Pneumocandins/Echinocandins The echinocandins inhibit formation of beta(1,3)-d-glucans in the fungal cell wall. The prototype drug is caspofungin acetate. Other drugs in this class are micafungin and anidulafungin. Caspofungin is given once daily as a slow IV infusion. Caspofungin is effective against resistant Candida albicans, and it also has efficacy against Aspergillus. It is ineffective against Cryptococcus. Cost is slightly less than for lipid formulations of AMB, but nevertheless the need for daily IV infusion together with the cost means it is rarely used in veterinary medicine at this time. In addition, the optimum dose for dogs and cats and its adverse effects in these species are not known. Terbinafine Terbinafine (LamasilÒ) inhibits fungal squalene epoxidase, blocking fungal ergosterol synthesis. Terbinafine is well absorbed, although there is a high hepatic first pass effect in humans. It accumulates in skin, nails and fat. In 70

71 veterinary medicine, it has been most commonly used to treat dermatophytosis, and it is well tolerated. Its efficacy for invasive fungal infections has not been well investigated, although there are a few published and some anecdotal reports of its use to successfully treat some deep mycoses, especially when used in combination with other drugs. Table. Commonly used drugs for treatment of deep mycoses in dogs and cats Drug Dose Range Frequency Route Deoxycholate amphotericin B AbelcetÒ (amphotericin B lipid complex) Dogs: 0.5 mg/kg in 1 L D5W Cats: 0.25 mg/kg in 250 ml D5W Dogs: 2-3 mg/kg Cats: 1 mg/kg Mon-Wed-Fri until a total dose of 4-6 mg/kg or azotemia occurs* Mon-Wed-Fri for 9-12 treatments* Flucytosine 125 mg per cat q6 8 h PO Itraconazole Cats: 3 mg/kg q24h (suspension) PO Dogs: 5 mg/kg q12-24h Fluconazole Cats: 50 mg/cat/d Dogs: 5-10 mg/kg/d q24h; divide high doses and give q8-12 PO h q24h Terbinafine Cats: mg/kg Dogs: 10 mg/kg PO Check BUN and creatinine prior to each administration. Discontinue if azotemia occurs. Selected References IV over 4-6 h IV; dilute in D5W to 1 mg/kg; give over 1-2 h 1. Spector D, Legendre AM, Wheat J, et al. Antigen and antibody testing for the diagnosis of blastomycosis in dogs. J Vet Intern Med 2008;22: Foy DS, Trepanier LA, Kirsch EJ, et al. Serum and urine Blastomyces antigen concentrations as markers of clinical remission in dogs treated for systemic blastomycosis. J Vet Intern Med 2014;28: Cook AK, Cunningham LY, Cowell AK, et al. Clinical evaluation of urine Histoplasma capsulatum antigen measurement in cats with suspected disseminated histoplasmosis. J Feline Med Surg 2012;14: Wheat LJ, Freifeld AG, Kleiman MB, et al. Clinical practice guidelines for the management of patients with histoplasmosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis 2007;45: Vishkautsan P, Papich MG, Thompson G, et al. Pharmacokinetics of Voriconazole in Healthy Cats Following Intravenous and Oral Administration. Am J Vet Res 2016;77:

72 6. Kendall J, Papich MG. Posaconazole pharmacokinetics after administration of an intravenous solution, oral suspension, and delayed-release tablet to dogs. Am J Vet Res 2015;76: Mawby DI, Whittemore JC, Fowler LE, et al. Posaconazole pharmacokinetics in healthy cats after oral and intravenous administration. J Vet Intern Med 2016;30:

73 VETERINARY TECHNICIAN PROGRAM PROCEEDINGS January 27,