The Use of Voriconazole for the Treatment of Aspergillosis in Falcons (Falco Species)

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1 Journal of Avian Medicine and Surgery 21(4): , by the Association of Avian Veterinarians The Use of Voriconazole for the Treatment of Aspergillosis in Falcons (Falco Species) Antonio Di Somma, Med Vet, SMPA, Tom Bailey, BVSc, MRCVS, MSc, PhD, CertZooMed, Dipl ECAMS, Christudas Silvanose, BMLT, and Celia Garcia-Martinez, Lic Vet, MSc, MRCVS Abstract: To evaluate the clinical efficacy and safety of voriconazole for the treatment of aspergillosis in falcons, 20 falcons with aspergillosis admitted to the Dubai Falcon Hospital from August 2003 to May 2006 were treated with voriconazole. These falcons included 6 gyrfalcons (Falco rusticolus), 10 gyrfalcon hybrids, 1 lanner (Falco biarmicus), 1 saker (Falco cherrug), and 2 peregrine falcons (Falco peregrinus). Clinical signs were weight loss, inappetence, dyspnea, inspiratory stridor, tachypnea, and biliverdinuria. Aspergillosis was diagnosed from clinical signs, hematologic results, radiographic abnormalities, endoscopic examination of the lower respiratory tract, cytologic examination of biopsy samples from air sacs, and fungal cultures. Birds treated with voriconazole administered by crop gavage were divided into 2 groups: in group 1, birds were treated with 12.5 mg/kg q12 h for 3 days (loading dose), then q24h for an additional 18 to 87 days; in group 2, birds were treated with 12.5 mg/kg q12h for the full period of 44 to 100 days. Treatment with voriconazole resulted in a successful clinical response in most cases, an acceptable survival rate, and few adverse effects. Complete clinical resolution occurred in 14 birds (70%), a partial response in 5 birds (25%), and 1 bird (5%) died during treatment. From these results, voriconazole appeared to be effective and safe for the treatment of aspergillosis in some species of falcons. Key words: aspergillosis, Aspergillus fumigatus, endoscopy, antifungals, voriconazole, avian, falcons, Falco species Clinical Report Aspergillosis remains a significant cause of morbidity and mortality in animals and humans, despite advances in medicine and the emergence of new antifungal agents. 1 3 The genus Aspergillus is composed of approximately 600 species. 4 The agent most commonly associated with disease in humans and animals is Aspergillus fumigatus, which forms 3- to 4-cm colonies on Sabouraud s dextrose agar and animal tissues within a period of 7 days. 5 The flat colonies are initially white, then become blue-green as conidia begin to mature. In birds, aspergillosis is also commonly caused by A fumigatus, whereas isolation of Aspergillus flavus is less common; other species that have been isolated include Aspergillus niger, Aspergillus terreus, Aspergillus nidulans, and Aspergillus glaucus. 5 Manifestations of the disease From the Dubai Falcon Hospital, PO Box 23919, Dubai, United Arab Emirates. relate to which organs are involved and whether infection is localized or disseminated. 5 Aspergillosis is not a transmissible disease, and infections are acquired from environmental exposure. 6 Disturbances of soil or movement of hay or litter can produce aerosols, which expose the respiratory tract to conidia. 7 Severely immunocompromised individuals are at risk of developing this opportunistic infection. Aspergillosis in birds is usually confined to the lower respiratory system, with florid lesions developing in the air sacs and lungs. Less commonly, infection involves the eyes, brain, skin, and joints. 5 Aspergillosis is the most commonly occurring disease among wild birds held in captivity and is an occasional problem in companion birds. 8,9 Among raptors, the species most susceptible to the disease are the goshawk (Accipiter gentiles), gyrfalcon (Falco rusticolus), snowy owl (Nyctea scandiaca), rough-legged hawk (Buteo lagopus), immature red-tailed hawk (Buteo jamaicensis), and golden eagle (Aquila chrysaetos). 9 Species 307

2 308 JOURNAL OF AVIAN MEDICINE AND SURGERY considered more resistant are the prairie falcon (Falco mexicanus) and Harris hawk (Parabuteo unicinctus). The bald eagle (Haliaeetus leucocephalus) is more susceptible to aspergillosis in the presence of lead toxicosis. 9 In the Middle East, aspergillosis is the most important disease affecting falcons, especially during the training and hunting season. 10 Predisposing factors include inadequate nutrition, poor ventilation in rooms where birds are housed, stress, and adverse climatic situations, particularly in falcons that originate from other geographic regions. The limitations of current therapies used to treat aspergillosis are tolerance problems, nephrotoxicity with amphotericin B, and poor oral bioavailability with itraconazole. 11 Voriconazole is a novel, broad-spectrum, triazole antifungal with good activity in vivo and in vitro against Aspergillus species. 3 In this study, we describe the diagnosis of aspergillosis and the efficacy of treatment with voriconazole in falcons presented with clinical disease. Falcons During the period of August 12, 2003, to May 25, 2006, a total of 20 falcons with aspergillosis were admitted to the Dubai Falcon Hospital for treatment with voriconazole. The birds included 6 gyrfalcons (F rusticolus), 10 gyrfalcon hybrids, 1 lanner (Falco biarmicus), 1 saker (Falco cherrug), and 2 peregrine falcons (Falco peregrinus), all hunting falcons belonging to the royal family of Dubai and undergoing training at the time of admission. The group of 20 birds was selected with approval of the trainers. Thirteen birds were females, and 7 were males. Age was determined by plumage: 17 birds were juveniles (hatch-year birds), and 3 were adults (with plumage after the first molt). Affected falcons showed general clinical signs of weight loss, muscle wasting, inappetence, exercise intolerance, prolonged tachypnea after handling or flight, depression, dyspnea, inspiratory noise, and biliverdinuria. The falcons included in the study were housed individually under defined environmental conditions in indoor enclosures (isolation room m) maintained at 20u 22uC with a 12-hour photoperiod. The birds diet during the study was eviscerated quail meat fed once daily at midmorning and a vitamin supplement (Vitahawk, D.B. Scientific, Oakley, CA, USA) fed twice weekly. Birds had free access to fresh drinking water at all times. Clinical examinations All the birds were anesthetized and subjected to a thorough clinical evaluation, including physical examination, evaluation of fecal and crop samples for parasites, a complete blood cell (CBC) count and plasma biochemical analysis, whole body survey radiographs, and endoscopic examination of the lower respiratory tract. Anesthesia was induced with a combination of ketamine (3 mg/kg IM) and medetomidine (60 mcg/kg IM; Domitor, Novartis Animal Health, Australasia Pty Ltd, Basal, Switzerland) and was maintained with isoflurane in oxygen delivered by face mask and adjusted to individual patient requirements. When the procedure was completed, the action of medetomidine was reversed with atipamezole (150 mcg/kg IM; Antisedan, Novartis). A 1-ml blood sample was collected from each bird with a 26-gauge needle attached to a 1-ml insulin syringe. The blood was placed in tubes that contained ethylenediaminetetraacetic acid (EDTA) for the CBC and lithium heparin anticoagulant for plasma biochemical analysis. Manual hematology by using standard techniques was conducted at the in-house laboratory. Samples for biochemical analysis were centrifuged at 1500g for 10 minutes immediately after collection. Plasma was collected and evaluated by using a Mira Plus chemistry analyzer (ABX Diagnostics, Sheffield, UK). The biochemical panel included uric acid, alanine aminotransferase, aspartate aminotransferase, creatinine phosphokinase, lactate dehydrogenase, total protein, cholesterol, and phosphorus. Ventrodorsal and lateral whole-body survey radiographs were obtained by using standard techniques. Because radiographic changes are usually only evident in birds with advanced cases of aspergillosis, greater diagnostic sensitivity is afforded through endoscopy. An endoscopic system specifically designed for birds (Karl Storz Veterinary Endoscopy America Inc, Goleta, CA, USA) was used for the endoscopic examinations; this consisted of a rigid, 2.7-mm, 30u telescope inside an examination sheath, and biopsy and grasping forceps Endoscopic procedures were observed with an endovision video camera and monitor. The endoscopic examination included evaluation of the trachea and air sacs. The bird was placed on a thermostatically controlled heating table (38uC). A standard left and right lateral approach with the pelvic limb extended caudally was used for endoscopy. A small skin incision was made between the last 2 ribs for entry of the

3 DI SOMMA ET AL USE OF VORICONAZOLE FOR THE TREATMENT OF ASPERGILLOSIS 309 Figure 1. Endoscopic biopsy of an aspergilloma in a gyrfalcon. Biopsy forceps are visible on the left. endoscope into the caudal thoracic air sac; the abdominal and cranial thoracic air sacs, as well as the ventrolateral aspect of the lung, could be accessed from this entry site. During endoscopic examination of each bird, at least 2 tissue samples were collected from affected areas of the respiratory tract. Biopsy forceps (Fig 1) or air-sac lavage was used to collect samples for fungal culture and cytologic examination, and impression smears were made on glass slides. The incision site was closed with 4-0 polydioxanone suture. Impression smears were air-dried, fixed, and stained with Neat stain (Astral Diagnostics, West Deptford, NJ, USA). Samples for fungal culture were plated on Saboraud s chloramphenicol agar and placed in an incubator at 37uC for 3 to 5 days. Classification of aspergillosis The clinical, radiologic, and clinicopathologic features of each bird were evaluated, and the degree of aspergillosis was classified. Criteria for grade 1 (early aspergillosis) were airsacculitis, few endoscopic lesions (,5-mm diameter) (Figs 2 and 3), culture and cytologic results positive for Aspergillus species, no detectable clinical signs, and only slight changes in the CBC results. Criteria for grade 2 (intermediate aspergillosis) were multiple air-sac granulomas and plaques (5- to 10-mm diameter) (Fig 4), leukocytosis and heterophilia, minimal radiographic lesions, and Figure 2. Endoscopic view of the caudal thoracic air sac of a falcon with early aspergillosis, demonstrating increased opacity and vascularity, and the presence of small plaques (,5 mm). culture and cytologic results positive for Aspergillus species. Grade 3 (advanced aspergillosis) criteria were large and coalescing air-sac granulomas (.10-mm diameter) (Figs 5 and 6), marked leukocytosis and heterophilia, general clinical signs of malaise, easily detectable radiographic lesions in air sacs and/or lungs, and culture and cytologic results positive for Aspergillus species. Treatment protocols All birds were treated with voriconazole (Vfend, Pfizer, Amboise Cedex, France) delivered by crop gavage at least 1 hour before feeding. A liquid formulation of voriconazole was achieved by crushing a 50-mg tablet into a fine powder, which was then mixed with 5-ml tap water. The falcons were divided into 2 treatment groups. The dosage of voriconazole for birds in group 1 (n 5 14) was 12.5 mg/kg q12h for 3 days (loading dose), then q24h until the end of treatment, whereas birds in group 2 (n 5 6) were treated at a dosage of 12.5 mg/kg q12h throughout the entire treatment period. The once daily treatment regimen was used for birds presenting during the period of August 2003 to April With 1 exception, subsequent birds were treated by the twice daily protocol. The single bird received once daily treatment because of its stress level in the hospital. Treatment was administered for a period of 18 to 100 days (median, 44 days). All birds were hospi-

4 310 JOURNAL OF AVIAN MEDICINE AND SURGERY Figure 3. Endoscopic view of the caudal lung in a falcon with early aspergillosis, demonstrating congestion and small granulomas. Figure 5. Endoscopic view of a large sporulating granuloma (.10 mm) in the caudal thoracic air sac of a falcon with advanced aspergillosis. talized in individual chambers to enable observation of adverse effects during the treatment period. Five of the 20 birds were nebulized with an intravenous formulation of voriconazole (20 mg in 20 ml saline solution; Vfend, 200 mg powder for solution infusion, Pfizer), in addition to the oral treatment (Table 3). Birds were nebulized once daily for 60 minutes in an enclosed chamber. An ultrasonic nebulizer delivered nebulization drops that weighed,5 ng. Surgery was performed on 12 birds to remove caseous material and fungal granulomas; this group included 6 birds with grade 3, 5 birds with grade 2, and 1 bird with grade 1 aspergillosis (Table 1). Surgical treatment included debridement and curettage. In 4 of the 12 surgical cases, Figure 4. Endoscopic view of granulomas (,10 mm) in the caudal thoracic air sac of a falcon with intermediate aspergillosis. Figure 6. Endoscopic view of granulomas in the ostium of a falcon with advanced aspergillosis.

5 DI SOMMA ET AL USE OF VORICONAZOLE FOR THE TREATMENT OF ASPERGILLOSIS 311 Table 1. Outcomes of 20 falcons with different grades of aspergillosis treated with 2 different dosages of voriconazole. Species Treatment Additional group a Grade b therapy Treatment duration (days) Outcome Gyrfalcon 3 red-naped shaheen 1 1 n/a 18 Resolved Gyrfalcon 3 saker 1 3 Surgery 58 Partial response Gyrfalcon 3 saker 1 2 n/a 41 Resolved Gyrfalcon 3 lanner 1 3 Surgery 31 Partial response Gyrfalcon 3 lanner 1 3 Nebulization c 87 Failure surgery Gyrfalcon 3 peregrine 1 1 n/a 27 Resolved Gyrfalcon 3 peregrine 1 1 n/a 44 Resolved Gyrfalcon 3 peregrine 1 2 Nebulization c 56 Resolved surgery Gyrfalcon 1 2 Surgery 43 Resolved Gyrfalcon 1 2 Surgery 68 Resolved Gyrfalcon 1 3 Surgery 39 Resolved Gyrfalcon 1 1 n/a 25 Resolved Lanner 1 2 n/a 58 Resolved Peregrine 1 2 Nebulization c 42 Resolved surgery Gyrfalcon 3 peregrine 2 2 Nebulization c 75 Partial response Gyrfalcon 3 saker 2 3 Surgery 60 Resolved Saker 2 3 Surgery 98 Partial response Gyrfalcon 2 2 Surgery 44 Resolved Gyrfalcon 2 3 Surgery 100 Partial response Peregrine 2 1 Nebulization c 49 Resolved a Group 1, voriconazole dosage of 12.5 mg/kg q12h for 3 days then q24h; group 2, voriconazole dosage of 12.5 mg/kg q12h. b Grade 1 (early aspergillosis): airsacculitis, few endoscopic lesions (,5-mm diameter), culture and cytology positive for Aspergillus, no detectable clinical signs, slight changes in CBC count; grade 2 (intermediate aspergillosis): multiple air-sac granulomas and plaques (5- to 10-mm diameter), leukocytosis and heterophilia, minimal radiographic lesions, culture and cytology positive for Aspergillus; grade 3 (advanced aspergillosis): large and coalescing air-sac granulomas (.10-mm diameter), marked leukocytosis and heterophilia, general clinical signs of malaise, easily detectable radiographic lesions in air sacs and/or lungs, culture and cytology positive for Aspergillus. c Nebulization with voriconazole. the air sacs were flushed with voriconazole (25 mg in 20 ml 0.9% sterile saline solution). After surgical debridement, each individual was also treated with a 5-day course of marbofloxacin (15 mg/kg IM q12h; Marbocyl 10%, Vetoquinol, Lure Cedex, France). Anorectic birds were provided with supportive care, including fluid therapy (30 ml/kg SC q12h; 10 ml/kg IV q12h; compound sodium lactate [Hartmann s/ringer solution]) and gavage feeding (40 50 ml/kg q12 h of minced whole quail, chicken breast, and whole egg) for up to 3 days, until the bird was eating on its own. All birds treated with voriconazole were weighed daily at 8 AM and were observed for adverse effects of treatment. At 2-week intervals, each bird was anesthetized with isoflurane and subjected to a thorough clinical examination. Ventrodorsal and lateral whole-body survey radiographs were obtained, and endoscopy was used to assess the progression of lesions in the lower respiratory tract. Evaluation protocol The criteria for a complete response to treatment with voriconazole were resolution of clinical signs of aspergillosis, negative culture or cytologic results from biopsy samples, hematologic parameters within reference intervals for the species, and normal endoscopic (Figs 7 and 8) and radiographic examinations. A partial response to treatment required complete resolution of attributable clinical signs, normal hematologic values, negative culture and cytologic results, and at least 70% improvement in radiographic and endoscopic abnormalities. Failure required evidence of clinical or radiographic deterioration (including death during therapy) or early discontinuation because of intolerance to the drug. Within 3 to 26 months after treatment ended, a complete health check was performed in 13 of the 20 study birds. During this period, 8 of the birds were also closely observed in the field-

6 312 JOURNAL OF AVIAN MEDICINE AND SURGERY Figure 7. Endoscopic view of the healed ostium of the falcon described in Figure 6 at the end of 6 weeks of treatment with voriconazole. training program to assess their fitness level during athletic flight exercises. Statistical analysis of the hematologic and biochemical values obtained before and after treatment was conducted by using Medcalc (Medcalc software, Mariakerke, Belgium). Significance was set at P,.05. Because data were not normally distributed, differences in hematologic and biochemical values between these 2 groups were analyzed for statistical significance by a paired Wilcoxon test. Clinical examinations In all 20 birds, endoscopic examination revealed generalized airsacculitis with thickened and opaque air sacs and multifocal white-toyellow granulomas or necrotic foci (from small caseous nodules to large coalescing plaques). Cytologic evidence of Aspergillus infections included inflammatory cells (heterophils, macrophages, and giant cells), an inflammatory response in the cells lining the air sacs (vacuolation, giant cell formation, and metaplasia), and fungal spores (coniodospores) or septate hyaline hyphae. Pretreatment and posttreatment hematologic and plasma biochemical results for 17 and 10 birds are listed in Tables 2 and 3, respectively. All results were compared with published reference values At the time of initial diagnosis, the results from all birds showed mild-to-severe leukocytosis (n 5 18), heterophilia (n 5 19), monocytosis (n 5 Figure 8. Endoscopic view of clear air sacs in a falcon that had been treated with voriconazole for 10 weeks for advanced aspergillosis. 9), low hemoglobin concentration (n 5 1), and low packed cell volume (n 5 1). In 3 cases, blood samples collected at the end of treatment were processed with an automatic hematologic analyzer (Cell Dyn 3500, Abbott Laboratory, Abbott Park, IL, USA). Because a different methodology was used in these cases, the hematologic results from these birds were excluded from the comparison of results at the time of initial diagnosis and the conclusion of therapy. In the other 17 birds, all hematologic values were within reference intervals by the conclusion of therapy. In the 10 birds for which plasma biochemical results were available before and after treatment with voriconazole, the mean levels of all biochemical parameters were within reference intervals by the time therapy was completed. Radiographic abnormalities were seen in 15 birds. These included a prominent bronchial pattern, asymmetry of the air sacs because of air sac consolidation or hyperinflation, and focal densities within the lungs or air sacs. Fungal isolates were identified after 3 to 4 days from biopsy samples submitted for fungal culture, and colony morphologies reflected various species of Aspergillus. The fungi were identified by standard techniques and included Afumigatus(n 5 9), Aflavus(n 5 2), Aniger(n 5 3), A terreus (n 5 4), and undetermined Aspergillus species (n 5 2).

7 DI SOMMA ET AL USE OF VORICONAZOLE FOR THE TREATMENT OF ASPERGILLOSIS 313 Table 2. Hematologic results (mean 6 SEM and minimum-maximum values) of 17 falcons with aspergillosis before and after treatment with voriconazole. Analyte Before treatment After treatment Hemoglobulin (g/dl) Packed cell volume (%) WBC (310 3 /dl) a a Heterophils (310 3 /dl) a a Lymphocytes (310 3 /dl) Monocytes (310 3 /dl) a a Eosinophils (310 3 /dl) Basophils (310 3 /dl) a Significant difference at P,.05. Aspergillosis classification and other diseases In the group of 20 birds, 5 birds had grade 1 aspergillosis, 8 birds had grade 2, and 7 birds had grade 3 (Table 1). Other underlying diseases detected on first presentation were coccidiosis (n 5 4), bacterial airsacculitis (n 5 1), trematodiasis (n 5 1), capillariasis (n 5 1), serratospiculiasis (n 5 4), ectoparasite infestation (n 5 1), trichomoniasis (n 5 1), avipox (n 5 1), and pododermatitis (n 5 1). Clinical outcome Endoscopic examinations revealed marked improvement of the surface of the air sacs and lungs as early as 15 days after initiating treatment Table 3. Plasma biochemical results (mean 6 SEM and minimum maximum values) of 10 falcons with aspergillosis before and after treatment with voriconazole. Analyte Before treatment After treatment Alanine aminotransferase (U/L) a a Aspartate aminotransferase (U/L) Cholesterol (mg/dl) Creatinine phosphokinase (U/L) Glucose (mg/dl) Lactate dehydrogenase (U/L) Phosphorus (mg/dl) Total protein (g/dl) Urea (mg/dl) Uric acid (mg/dl) a Significant at P,.05.

8 314 JOURNAL OF AVIAN MEDICINE AND SURGERY with voriconazole. Complete clinical resolution occurred in 13 of the falcons, a partial response was observed in 6 birds, and only 1 bird failed to respond to treatment with voriconazole (Table 1). Complete resolution occurred in all 5 grade 1 cases,6ofthe8grade2cases,and2ofthe7grade 3 cases. Partial resolution occurred in 2 of the grade 2 cases and 4 of the grade 3 cases. The one failure was a bird with grade 3 aspergillosis. Nineteen birds survived to the end of treatment. During the course of treatment, 4 birds developed secondary bacterial airsacculitis subsequent to endoscopic removal of caseous material. One of the falcons presented with hepatomegaly and high liver enzyme and bile acid concentrations after 1 week of treatment with voriconazole and was considered to be in hepatic failure. Other signs of toxicity were recorded in this gyrlanner falcon, including anorexia, flicking meat, and neurologic signs that required suspending the drug and initiating supportive therapy (forcefeeding and fluids). Because of adverse reactions, antifungal treatment was discontinued in this bird, and, finally, the Aspergillus species (a mixed infection of A fumigatus and Aniger)showedan in vivo resistance to voriconazole therapy. In general, adverse reactions to treatment with voriconazole included flicking meat (n 5 2), vomiting (n 5 2), and anorexia (n 5 2); the latter were episodic and did not require suspending voriconazole therapy. Thirteen of the 19 surviving birds were presented for follow-up examinations within 3 to 26 months after the conclusion of therapy with voriconazole. Twelve of these birds were considered to have complete resolution of disease. In addition, the athletic fitness of 8 falcons after treatment was checked after long-distance flights chasing wild prey: 7 of those birds demonstrated high-level fitness. Discussion Our results demonstrate that oral administration of voriconazole by crop gavage, either twice a day for 3 days (loading dose) then once a day, or twice a day for the entire treatment period, provides adequate treatment of aspergillosis in falcons. Treatment with voriconazole resulted in a successful clinical response in most cases, an acceptable survival rate, and few adverse effects. In birds, aspergillosis is often insidious at the onset and is slowly progressive, so early diagnosis is important. Clinical signs, which are nonspecific and depend on the organ system(s) involved, are often inapparent until fungal colonization is extensive. Aspergillosis is usually differentiated from other avian respiratory diseases by radiographic opacities in the air sacs and granulomatous lesions observed during endoscopic examination. Exudative fibrinous or purulent airsacculitis is also frequently seen in cases of mycoplasmosis, colibacillosis, and chlamydophilosis. Mycobacteriosis and other mycoses should also be considered in cases of granulomatous disease. 5 A mild-to-severe leukocytosis is typically present in birds with aspergillosis, and the differential CBC reveals a heterophilia with a left shift, monocytosis, and lymphopenia. A definitive diagnosis is based on identifying the organism on culture and cytologic examination of the lesions. Aspergillus species are ubiquitous saprophytes; therefore, diagnostic samples should be carefully collected by aseptic techniques. 5 Treatment of aspergilllosis is often difficult, because infections caused by Aspergillus species tend to become encapsulated by the bird s inflammatory response and are consequently isolated from the circulation. 18 The prognosis is poorer if one must rely only on the systemic administration of antifungal agents. Optimal treatment regimens include debriding lesions, followed by topical therapy administered in conjunction with early, aggressive, systemic antifungal treatment. 18 Topical therapy may be achieved by nebulization or surgical air sac flushing. 18 Traditional treatment for aspergillosis infections in birds involves the use of amphotericin B, itraconazole, and terbinafine. 19,20 Voriconazole, a second-generation triazole, was approved by the Food and Drug Administration in 2002 for use in people with invasive aspergillosis, Fusarium and Scedosporium infections, and resistant candidiasis. 21,22 It has some distinct benefits compared with currently available antifungal agents, such as reliable oral bioavailability and excellent activity against many Aspergillus species that are resistant to currently available therapy. 23,24 Voriconazole is also used in patients who cannot tolerate other therapies. Most adverse events seen with voriconazole are similar to those seen with other triazole drugs and are not life threatening. 22 In a recent study, the MIC of voriconazole against Aspergillus strains isolated from falcons was found to be consistent with that reported in human studies. 25 In the study cited, 95% and 100% of fungal isolates, including A fumigatus, A flavus, Aniger, anda terreus, were susceptible to voriconazole at MICs #0.38 mg/ml and,1 mg/

9 DI SOMMA ET AL USE OF VORICONAZOLE FOR THE TREATMENT OF ASPERGILLOSIS 315 ml, respectively. By comparison, 21% of isolates, including A fumigatus (27.6%), A flavus(16.6%), A niger (100%), and A terreus (23%), were resistant to itraconazole (MIC $ 1 mg/ml). 25 Results of another recent study in falcons demonstrated that voriconazole at a dosage of 12.5 mg/kg PO q12h provided plasma concentrations.0.5 mg/ml for 14 days. 26 Infection with Aspergillus species should be considered to occur secondary to an immunosuppressive event. 5 Although there was no evidence of a primary disease that immunocompromised the birds in this study, environmental factors may have caused physical stress that predisposed the birds to systemic fungal infection. Because voriconazole is metabolized by the liver, liver function tests should be evaluated at the onset and during the course of therapy to monitor for hepatic damage. 21 High serum concentrations of aspartate aminotransferase and lactate dehydrogenase found in falcons in this study were shown to occur with liver or muscle damage. Changes observed in birds in this study were most likely caused by muscle or tissue injury associated with repeated venipuncture. The treatment protocols and voriconazole dosages in falcons suggested by this study are based on the results in 20 birds housed in a strictly controlled environment. Whether these protocols are applicable to other avian species or to birds in other environmental conditions remains to be determined. Acknowledgments: We dedicate this study to H.H. Sheikh Hamdan bin Rashid al Maktoum, a lifelong falconer and the father of falcon medicine in the Middle East. We thank our veterinary technicians, Mr Ahmed Kutty and Mr Rejimon Joseph, for their assistance in this study. We thank Humaid Obaid al Muhairy, general manager of the hospital, for his continuing encouragement. References 1. Verweij PE, Denning DW. Diagnostic and therapeutic strategies in invasive aspergillosis. Sem Resp Crit Care. 1997;18: Denning DW. Therapeutic outcome in invasive aspergillosis. Clin Infect Dis. 1996;23: Del Favero A, Gluckman E, Ruhnke M, et al. The efficacy and tolerability of UK 109,496 (voriconazole) in the treatment of invasive aspergillosis. Proc Cong Inter Soc Human Animal Mycology. Parma, Italy; 1997;13: Santos RM, Firmino AP, Felix CR. Keratonolytic activity of Aspergillus fumigatus. Curr Microbiol. 1996;33: Kunkle RA. Fungal infections. In: Saif YM, Barnes HJ, Glisson JR, et al, eds. Diseases of Poultry. Ames, IA: Iowa State Press; 2003: Bauck L. Mycoses. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Application. Lake Worth, FL: Wingers Publishing; 1994: Redig P. Fungal diseases. In: Samour J, ed. Avian Medicine. Philadelphia, PA: Mosby; 2000: Aguilar RF, Redig PT. Diagnosis and treatment of avian aspergillosis. In: Bonagura JD, ed. Current Veterinary Therapy XII. Philadelphia, PA: WB Saunders; 1995: Redig PT. Avian emergencies. In: Beynon PH, Forbes NA, Harcourt Brown NH, eds. Manual of Raptors, Pigeons and Waterfowl. Cheltenham, UK: BSAVA; 1996: Samour JH. Veterinary considerations during the hunting trip. In: Lumeij JT, Remple JD, Redig PT, et al, eds. Raptor Biomedicine III. Lake Worth, FL: Zoological Education Network; 2000: Denning DW, Lee JY, Hostetler JS, et al. NIAID mycoses Study Group multicenter trial of oral itraconazole therapy for invasive aspergillosis. Am J Med. 1994;97: Taylor M. Endoscopic examination and biopsy techniques. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Application. Lake Worth, FL: Wingers Publishing; 1994: Taylor M. Endoscopic diagnosis of avian respiratory tract diseases. Semin Avian Exotic Pet Med. 1997;6: Hernandez-Divers SJ. Endosurgical debridement and diode laser ablation of lung and air sac granulomas in psittacine birds. J Avian Med Surg. 2002;16: Samour J. Hematology reference values. In: Samour J, ed. Avian Medicine. Philadelphia, PA: Mosby; 2000: Muller M, George GR, Mannil AT. Haematological values of gyr hybrid falcons. Proc Eur Assoc Avian Vet. 2005: Wernery R, Wernery U, Kinne J, Samour J. Haematology and blood biochemistry. In: Wernery R, Wernery U, Kinne J, Samour J, eds. Colour Atlas of Falcon Medicine. Hannover, Germany: Schütersche; 2004: Oglesbee BL. Mycotic diseases. In: Altman RB, Clubb SL, Dorrestein GM, Quesenberry K, eds. Avian Medicine and Surgery. Philadelphia, PA: WB Saunders; 1997: Orosz SE. Overview of aspergillosis: pathogenesis and treatment options. Semin Avian Exotic Pet Med. 2000;9: Orosz SE, Frazier DL. Antifungal agents: a review of their pharmacology and therapeutic indications. J Avian Med Surg. 1995;9: VFEND (voriconazole) tablets and injection (package insert). New York: Pfizer, 2002.

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