Selected Zoonoses of TN: Prevention and Control John C. New, Jr., DVM, MPH, Dipl. ACVPM UT College of Veterinary Medicine Tennessee Public Health Association Franklin, TN August 27, 2008
There are over 150 diseases that potentially can be shared by people and animals. Animal Bites Rabies Bartonellosis Zoonotic Parasites Dermatophytes
Zoonoses Changing nature of human- animal relationships Pet ownership in 61% of US households and increasing Pets are viewed as family members and live in closer association than in previous generations
Zoonoses Increasing contact with growing wildlife populations Raccoons co-existing with humans in suburban neighborhoods, Large uncontrolled deer populations Recreational activities
ANIMAL BITES
Animal Bites An estimated 4.4 million animal bites occur annually in the U.S. (300 bites per 100,000 population). 2nd most costly public health problem in the country (behind STDs). Most dog bite victims are < 20 years of age and about 25% are < 9 years of age. About 65% of facial bites are in children < 10 years of age.
Animal Bites Most dogs involved in bites (80%( 80%) ) are owned and almost all fatalities are due to dogs owned by the family or known by the victim. Average of 17 human deaths annually due to dog attacks. Children 30 days old to 11 years accounted for 80% of fatalities).
Animal Bites Bites occur most often in warmer months (March-August) in the afternoon and early evening (between 3:00 and 7:00 pm). The animal bite problem is preventable through owner and public education, animal control at the community level, and bite reporting. Education efforts should be especially focused on children and their parents.
What we must prevent!
What we must prevent!
Treatment of Dog Bites by Selected TN Counties, 2004 County Knox Davidson Shelby Outpatients 533 665 831 Bites per 100,000 133.1 111.6 91.7 Inpatients 11 24 26 Bites per 100,000 2.7 4.0 2.9
Measures to Prevent Dog Bites Evaluate environment and lifestyle and consult with a professional to determine suitable breeds. Spend time with a dog before buying or adopting it. Spay/neuter virtually all dogs. Never leave infants or young children alone with any dog.
Measures to Prevent Dog Bites Properly socialize and train any dog entering the household. Do not play aggressive games with your dog (e.g., wrestling, tug-of of-war). Teach children basic safety around dogs and review regularly. R.U.F.U.S. Rules
R.U.F.U.S. Rules R = Respect U = Understand F = Friendly U = Unfriendly S = Stay Still
R.U.F.U.S. Rules
A community approach to dog bite prevention American Veterinary Medical Association Task Force on Canine Aggression and Human-Canine Interactions -JAVMA, Vol 218, No. 11, June 1, 2001
A community approach to dog bite prevention American Veterinary Medical Association Task Force on Canine Aggression and Human- Canine Interactions JAVMA, Vol 218, No. 11, June 1, 2001 http://www.avma.org/products/animal_welfare/dogbite.asp
American Veterinary Medical Association http://www.avma.org www.avma.org/
RABIES
Raccoon Rabies Rabies
Rhabdovirus Rabies virus Electron micrograph of rabies. The bullets surrounding the smooth gray circle are rabies. The circle itself is the Negri body.
Rabies Transmission Usually by a bite - other rare Bat to other species - may occur in absence of terrestrial animal reservoirs Aerosol (rare)- laboratory, bat caves? Human to human - transplant only
Period of Communicability Definition- the time during which a rabid animal is shedding virus in the saliva and therefore capable of transmitting rabies to a susceptible host. Dogs, cats and ferrets may shed up to 3 days prior to clinical signs and 3-53 5 days after clinical signs until death. Other species- unknown Basis for 10-day quarantine of dogs, cats and ferrets that have bitten a person.
Cases of Raccoon Rabies, 2006
Changing Epidemiology of Raccoon Rabies
Cases of Bat Rabies, 2006
900 800 700 600 500 400 300 200 100 0 Wild and Domestic Animal Rabies Cases, Tennessee, 1946-2006 Canine variant Fox variant Domestic Wild Total Skunk variant 1952 1955 1958 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 Year 1946 1949 Number
Rabies- Incubation period Dog - average 3-83 8 weeks, 10 days to 6 months Cat (experimental)- 9-51 days, median 18 Ferret- preliminary data 10-41 days People- average 1.5-4 mo (range, 9 days- 7yrs?) Extremes- >1 year wild animals & humans
Rabies- Sources of infection Human exposure usually from domestic animals or bats. Domestic animals acquire from wild animals Not self perpetuating in domestic animals except for dogs in Mexico, Latin America, Asia and Africa
Bats and rabies virus All 49 continental United States Ongoing work to associate strains with species and geographic location Strains differ from terrestrial mammals. Human deaths in U.S. 2000-2005 2005 Bat associated strains found in 9/10 of indigenous human cases 5 additional cases in transplant patients, all bat origin 1 case from raccoon strain
Rabies Surveillance in the United States, 2006 Animal rabies: 6,940 8.2% increase from 2005 92% wildlife Species composition: 37.7% raccoons 24.4% bats 21.5% skunks 6.2% foxes 4.6% cats 1.2% cattle 1.1% dogs
Laboratory-confirmed Rabies by County, Tennessee, 2007 Lauderdale Tipton Lake Dyer Obion Crockett Haywood Gibson Weakley Madison Carroll Chester Henry Henderson Benton Stewart Houston Humphreys Perry Hickman Lewis DecaturB-1 Montgomery Dickson Robertson Sumner Macon Cheatham Maury S-1 Davidson Williamson S-5 B -1 Marshall S-3 Bedford S-1 Trousdale Overton D-1 Jackson Smith Cw-1 Wilson D-1 Putnam B-1, S-1 Rutherford B-1 S-30 Coffee S-2 Cannon S - 2 Dekalb Warren S-3 Grundy Clay White Van Buren R-1 Unicoi Shelby B-1 Fayette B-1 Hardeman McNairy Hardin Wayne B-1 Lawrence Giles B-1 Lincoln C-1 S-2 Moore S-1 Franklin Marion Sequatchie Bledsoe Pickett Fentress Cumberland Rhea Meigs Morgan B-1 Scott B-1 Campbell Roane McMinn Anderson B-1 Loudon Monroe Union Knox B-3 Blount Claiborne Grainger Hamblen D -1, S-1 Jefferson S-3 D - 1 Sevier Hancock Hawkins B-1, S-1 Cocke B-1 Greene B-1 D-1 S-20 Washington S-5, R-14 Sullivan B-2, R-3 Carter R-1 Johnson R-2 Hamilton B-2 Bradley R-1 Polk Total 132 Dog (D) - 5 Cat (C)-1 Cattle (Cw)- 1 Skunk (S) - 82 Raccoon (R)- 21 Bat (B) - 22
Laboratory-confirmed Rabies By County, TN, 2008 through 16 June Lauderdale Tipton Lake Dyer Obion Crockett Haywood Gibson Weakley Madison Carroll Henry Henderson Chester Benton Decatur Stewart Houston Humphreys Perry Montgomery Lewis Dickson Hickman Robertson Sumner Macon Cheatham Maury Davidson Williamson S-2 Unicoi B-1, S-1 Shelby Fayette Hardeman McNairy Hardin Wayne Lawrence Giles Marshall S-3 D-1 Bedford S-1 Wilson Rutherford S-7 Trousdale S-3 Smith Cannon Coffee S-2 Jackson Dekalb Warren S-1 Grundy Clay Putnam White Overton Van Buren Lincoln S-3 D-1 Moore Sequatchie Bledsoe Pickett Fentress Cumberland Rhea Meigs Morgan Scott Roane B-1 Sevier McMinn Anderson Loudon Campbell Monroe B-1 Union Knox Blount Claiborne Grainger Hamblen Jefferson Hancock Hawkins S-1 Cocke Greene F-1, S-2 Washington S-1, R-2 Sullivan R-7, C-1, F-1 Carter F-3, R-3, S-2 Johnson R-2, F-1, S-1 Franklin S-1 Marion Hamilton R-1 Bradley Polk R-2 Total 60 Dog (D) - 2 Cat (C) 1 Fox (F)- 3 Skunk (S) - 31 Raccoon (R)- 17 Bat (B) - 3
Education Prevention Reducing risk Protecting pets through vaccination Increase surveillance USDA-Wildlife Services (> 20 East TN counties) Direct rapid immunohistochemical test (drit) Help prevent spread Oral rabies vaccination (ORV) campaign Control translocation
Rabies Surveillance
Individual human rabies prevention Human rabies is rare in the United States. Exposure & risk of transmission must be accurately assessed. Rabies post-exposure prophylaxis (rpep) if indicated is a medical urgency NOT a medical emergency.
Domestic Animals Vast majority of exposures are bites. Magnitude of rabies risk is less. All bites from domestic animals do not necessitate rpep.
BARTONELLOSIS Cat Scratch Disease Cat Scratch Fever
Etiologic organism Bartonella spp. At least 20 species Gram negative bacteria Highly adaptive to one or more mammalian hosts Survive intracellularly Helps promote persistent infections B. henselae lives in rbcs, endothelial cells rbcs = red blood cells
Etiologic organism Bartonella spp. recognized in people B. bacilliformis B. henselae B. vinsonii berkhoffii B. vinsonii arupensis B. quintana B. elizabethae B. clarridgeiae B. grahamii
Etiologic organism Bartonella spp. recognized in cats Bartonella henselae Classical etiologic agent of Cat Scratch Disease Bartonella clarridgeiae * Bartonella bovis Bartonella koehlerae Bartonella quintana * * may also be transmitted from cats to people
Etiologic organism Bartonella spp. recognized in dogs Bartonella vinsonii subspecies berkhoffii B. henselae, B. clarridgeiae,, and B. elizabethae B. vinsonii (berkhoffii) has recently been isolated from human blood samples in the US (All positive people have extensive animal and arthropod contact).
Etiologic organism Bartonella spp. recognized in ruminants B.. bovis in domestic cattle Likely also in elk, mule deer, other ruminants B. chomelii in domestic cattle
Reservoirs Domestic and Wild Mammals Canines (coyotes, gray foxes, dogs) Felines (domestic cats, pumas, bobcats, cheetahs, lions) Rodents, rabbits, raccoons, deer, cattle Loggerhead sea turtle, harbor porpoise Persistent bacteremia does not cause clinical illness in most reservoir hosts Typically only non-natural natural hosts become ill.
Transmission Cat Scratch Cat and Dog Bites Arthropod Vectors No vertical transmission during gestation or through milk No transmission during breeding
Cat to Cat Life Cycle and Transmission 1) Flea ingests Bartonella with cat blood during feeding Bacteremic Cat 2) Amplification of Bartonella in flea s hindgut 4) Flea bites cat, feces with Bartonella infects bite wounds, cat becomes bacteremic 3) Bartonella excreted in flea feces for at least 9 days; lands on new cat
Transmission: Cat to Human Cat scratches person (or bites) Bacteremic Cat Infected cat blood in claws contaminate person s wound Flea feces in claws contaminate wound and spread Bartonella to person
Transmission: Wildlife to Dogs Dogs are most likely accidental hosts, but they may be sentinels for infections in people
Transmission Arthropod Vectors implicated Cat fleas (vector for B. henselae) Biting flies (vector for (vector for B. henselae and B. bovis) Lice (vector for B. quintana) Sand flies (vector for B. bacilliformis) Ticks Rhipicephalus, Ixodes, Amblyomma, Dermacentor
Epidemiology Human cases 22,000 cases/year in US 9.3 cases of CSD/100,000 people/year Hospitalization rate for CSD 0.6/100,000 children under 18 yrs old 0.86/100,000 children under 5 yrs old
Epidemiology Seroprevalence in Dogs 3.6% dogs sick dogs in SE US had antibodies to B. vinsonii (berkhoffii) 28-35% coyotes seropositive Seroprevalence in Cats 40% of cats carry B. henselae at some time in their lives 28% southern CA, 33% FL, 12% DC, 6% Chicago
Epidemiology Seroprevalence in People 3.6-6% 6% seropositive for B. henselae in healthy people May be higher in at-risk people bacillary angiomatosis bacillary peliosis relapsing bacteremia
Epidemiology Most often children <10 years www.jr2.ox.ac.uk/bandolier/band146/b146-61.jpg Most infected cats are <2 years old
Epidemiology Risk factors for Human Exposure Cat scratches Ownership of young cats Flea and tick exposure Risk factors for Feline Seropositivity Flea infestation Warm climates with high precipitation Going outdoors Exposure to other cats
Epidemiology Seasonal Distribution Between July and January Corresponds with flea/tick seasons? By late summer and fall kittens are becoming juveniles Increased activity and rough play with kids By winter outdoor cats spend more time indoors with closer human contact
Clinical Bartonellosis Overview Generally self limiting and mild Some subclinical infections Up to 25% result in serious systemic signs. Immunosuppressed patients may have more persistent and severe disease. Co-infections with other tick-borne diseases common in both people and dogs
Classic Cat Scratch Disease Cat scratch or bite Papule, then pustule Develops in 14 days Fever, Malaise Regional lymphadenopathy in weeks Often become abscessed Self-limiting limiting disease, but can take a while Usually does NOT respond to antibiotics Occurs mostly in immunocompetent people
Prevention of Bartonellosis Non-evidence based advice Declaw all cats Keep all cats indoors Keep all cats outdoors Euthanize all positive cats Treat all positive cats Encourage all immunosuppressed people to get rid of their cats
Prevention of Bartonellosis Evidence based recommendations Flea and tick prevention and control Maintain good hygiene around all pets Prevent cat scratches and bites Avoid aggressive play with young cats Keep cats nails trimmed or dull Clean any wounds with soap and water Do not allow cats to lick open wounds Consult physician if any concerns
Prevention of Bartonellosis Considerations for Immunosuppressed Clients: Recommend adult cats, not kittens Emphasize hygiene and gentle play Consider treating positive asymptomatic cats with a course of azithromycin No guarantee it will clear bacteremia May decrease risk of transmission
Bottom Line Cat scratches can be serious and even life threatening. Educate pet owners and keep reinforcing basic hygiene to kids and adults
ZOONOTIC PARASITES
Zoonotic Nematodes General Features Direct lifecycle parasites in their hosts People accidentally infected by ingestion of eggs/larvae or skin penetration by larvae Contact with fecally contaminated environment Frequent hand washing, pet hygiene, and periodic treatment of household pets
Zoonotic Toxocariasis Clinical disease in humans produced by Toxocara canis and Toxocara cati Accidental ingestion of infective eggs from fecally contaminated environments Common Prevalence in SE dogs pet nationwide, dogs (~17%) 14.5% and and cats, (26%)( Prevalence in puppies higher much higher (30% nationwide) (30% nationwide)
CDC Toxocariasis Toxocara canis T. cati In United States - estimated 10,000 cases of Toxocara infections yearly in humans
CAPC Three to six million people in the US are infected with Toxocara larva migrans each year, and the overall seroprevalence ranges from an average of 3.5 % to more than 23% in some areas. 25-33% of several thousand presumptive samples submitted by physicians to CDC each year, are seropositive.
Toxocara canis Animals < 6 months responsible for most environmental contamination Puppies infected in utero about 42 nd day of gestation (63 day gestation) Mature worms passing 10 3 eggs in puppies by 3 wks
Toxocara cati Adult felines play significant role in environmental contamination No in utero infection Kittens infected lactogenically
Toxocariasis/Toxocariosis Clinical disease in humans may be characterized by systemic (visceral or nerological) larval migrations (VLM, NLM) or ocular larval migrations (OLM). Humans infected by accidentally ingesting infective eggs from the environment from areas or articles previously contaminated with dog or cat feces.
Zoonotic Hookworms Ancylostoma caninum, A. braziliense, A. tubaeforme Relatively common parasite of cats and dogs (19% of US dogs) Infective larvae penetrate and migrate beneath skin of people, Creeping Eruption (Cutaneous Larva Migrans)
Intensely puritic, usually self-limiting, easily treated Ancylostoma brazilense
To prevent VLM, OLM, CLM Limit Exposure of Children to Contaminated Environments. Eliminate infections in puppies and kittens during prepatent period.
To prevent VLM, OLM, CLM Have at least biannual fecal exams of dogs and cats and treat all positives. Remove feces from yard, play areas. Keep sandboxes covered when not in use.
To prevent VLM, OLM, CLM Wash hands following pet contact. Do not allow children to kiss pets. Clean dogs and cats promptly if fecally contaminated
To prevent VLM, OLM, CLM Reduce the numbers of uncontrolled, ownerless dogs and cats as well as unwanted and poorly supervised pets. Prevent fouling of the pavements and public places with dog feces; exclude dogs from children's playgrounds (scoopers).
Zoonotic Baylisascariasis Clinical disease in humans produced by Baylisacaris procyonis Accidental ingestion of infective eggs from fecally contaminated environments Common throughout the USA 22% prevalence in nuisance raccoons trapped in Atlanta residential areas
Zoonotic Protozoa Toxoplasma gondii Giardia sp. Cryptosporidium
Toxoplasma gondii Unequivocal zoonotic parasite domestic and wild felidae primary source of all infections infectious oocysts passed in feces People and other intermediate hosts infected by oocysts or tissue stages
Toxoplasma gondii Public Health Significance Congenital birth defects, or abortion to fetus when mother acquires primary infection during pregnancy Cause of mortality for HIV and other immunocompromised persons
Oocysts (eggs) Which is Responsible for Disease? Tachyzoites Tissue Cyst Bradyzoites
Only Felidae are the definitive host. All Mammals and birds are Intermediate hosts
Tachyzoites become bradyzoites! Develop immunity to additional infection as cysts form in their tissues after infection. Chronic stage - persists for life of the patient without producing further problems.
Clinical Signs in humans and animals Flu-like symptoms that may last a month etc. Lymphadenopathy
Toxoplasmosis Infection with T. gondii is especially important in pregnant women If infected for the first time during pregnancy Miscarriage Mental retardation Severe birth defects
At Risk are Women Who Acquire a Primary Infection During or Shortly before Pregnancy Impact of T. gondii infection for the first time during pregnancy (seronegative women) Miscarriages Infection of the fetus Infant mortality 12% Birth defects 30%
60% of women who acquire a primary infection will transmit to fetus. Risk of transmission lower in wks 1-1 10 - but severe consequences. Wks 26-40 High risk infection mild toxoplasmosis
Congenital Toxoplasmosis Abortion or serious congenital birth defects more likely when infection occurs in 1 st Trimester Mild retardation, blindness, etc. when infected during 2 nd and 3 rd trimester Clinically apparent infections possible if infection occurs late in pregnancy (3 rd trimester)
Clinical Signs (Postnatal) In adults and children generally mild and mononucleosis-like Chills, fever, headache, myalgia, fatigue, and swollen lymph nodes Ocular disease (20 40 yrs) Many times subclinical
Congenital Toxoplasmosis Neonatal disease 15% of cases Infancy, childhood adolescent or adulthood 85% of cases
What Do Toxoplasma Titers Mean?
The animal has Toxoplasma gondii in its tissues
Can I measure the success of drug therapy by monitoring titers? Will titers disappear with treatment?
Will A Seropositive Cat Pass Oocysts? A Seronegative Cat? Which is better for a pregnant woman?
Toxoplasmosis Immunocompromised people are at risk for recrudescence of infection AIDS AIDS patients Cancer Cancer patients Organ Organ recipients
50% of all T. gondii Infections Foodborne?
Transmission to Humans Acquired Postnatal Infections: Fecally-contaminated contaminated environments Undercooked meat Unpasteurized milk Blood transfusions Organ transplant
RECOMENDATIONS Women should learn their T. gondii infection status when contemplating Pregnancy. Request a T. gondii IgG / IgM titer!
Safeguards From Infection Significant other should change cat litter box at least every 24 hours. If pg woman must change it, wear disposable gloves, mask, and wash hands with soap and water thoroughly afterwards. Feed cat commercial dry or canned food. Never feed cats raw meat.
Safeguards From Infection Keep indoor cats indoors. Avoid stray cats, especially kittens. Do not get a new cat during pregnancy. Cover outdoor sandboxes.
Safeguards From Infection Avoid gardening and contact with soil or sand. Wash and/or peel all fruits and vegetables before eating.
Safeguards From Infection Avoid drinking untreated water, particularly when traveling in less developed countries. Drink only pasteurized milk.
Safeguards From Infection Eat well cooked meat (no pink and juices clear) Internal temperature = 150-160 F. Do not sample meat until it is well cooked.
Safeguards From Infection Freeze meat for several days before cooking to reduce the chance of infection. Wash hands, knives, and food preparation surfaces thoroughly with hot soapy water after handling and contact with raw meat.
DERMATOPHYTES (RINGWORM)
Dermatophytes Ringworm is caused by a dermatophyte (fungus) infection of the skin. Microsporum canis Trichophyton mentagrophytes At least 4 other species
Dermatophytes Signs: hair loss, broken hairs, scaling, spreading reddened circular lesions (ringworm) that sometimes include vesicles.
Dermatophytes Signs: hair loss, broken hairs, scaling, spreading reddened circular lesions (ringworm) that sometimes include vesicles. The most common locations are the face (especially the beard), scalp and extremities.
Dermatophytes Differential diagnoses include contact allergic or irritant dermatitis, psoriasis, acne, and several other skin conditions that are not caused by fungi. Human infection is bothersome but rarely serious.
Dermatophytes Some animals can be carriers of the fungi and have no signs. Cats (especially kittens) are the major reservoir for M. canis and often have inconspicuous or subclinical infections.
Dermatophytes Definitive diagnosis is only possible by using culture techniques.
Dermatophytes Wood s s light ( black( light ) ) can be used to tentatively identify many M. canis infections (the hairs fluoresce) but is not helpful in the diagnosis of T. mentagrophytes.
Dermatophytes Infections are transmitted by contact with infected hairs or scales. Very young and elderly animals and people are more susceptible to infection. Infected animal hairs may contaminate the environment.
Dermatophytes - Control Use chlorhexidine (Nolvasan solution) Dilute 1 part stock solution in 4 parts water to wash cages, floors, and walls. Let cages dry before putting animals back in them. Water temperature must be at least 130ºF
Dermatophytes - Control Use chlorine bleach Dilute 1 part bleach with 10 parts water to wash cages, floors and walls Be sure to work in a well-ventilated area and wear protective clothing and gloves. Let cages dry before putting animals back in them. Water temperature must be at least 130ºF
Dermatophytes - Control If carpeting/upholstered furniture is contaminated: Vacuum thoroughly followed by steam cleaning using chlorhexidine at concentration above. Diluted bleach (see above) can be used to wipe down hard surfaces (linoleum, tile, etc.)
Dermatophytes - Control Observe precautions and water temperature requirements as noted previously. Change air conditioning or heating unit filters. Discard filters AND vacuum cleaner bags safely.
Acknowledgements UT College of Veterinary Medicine Dr. Sharon Patton Dr. Kate Stenske (Kansas( State U.) Dr. Michael Sims Dr. Bart Rohrbach TN Department of Health Dr. John Dunn USDA Wildlife Services Mr. Keith Wehner
Contact information John C. New, Jr., DVM, MPH, DACVPM Professor and Head Department of Comparative Medicine College of Veterinary Medicine University of Tennessee 2407 River Drive, Room A205 Knoxville, TN 37996-4543 (865) 974-5576, FAX (865) 974-5640 jnew@utk.edu