T. A. Bailey

Comparative morphology of the alimentary tract and its glandular derivatives of captive bustards

This study describes the gross anatomy of the alimentary tract of Houbara Bustards (Chlamydotis undulata macqueenii), Kori Bustards (Ardeotis kori), Rufous‐crested Bustards (Eupodotis ruficrista) and White‐bellied Bustards (Eupodotis senegalensis) maintained in captivity by the National Avian Research Center in the United Arab Emirates. The morphology of the alimentary tract and the proportions of each region were similar in all 4 species. The length of the oesophagus, combined proventriculus and ventriculus, small intestine, and large intestine formed 24.2–28.4%, 7.3–9.7%, 40.5–55.1% and 9.1–14.7% of the total alimentary tract length respectively. Neither crop nor oesophageal enlargement was observed in the birds examined in this study, although male Kori Bustards possessed a saccus oralis in the oropharyngeal cavity. Oesophagi, proventriculi, ventriculi, caeca and large intestine were well developed in all species. The small intestine was shorter than that of other avian herbivores and granivores when compared on a bodyweight basis. The well differentiated stomachs and well developed caeca of the bustards examined in this study are characteristic of omnivores. Analysis of the mean lengths of the alimentary tract components and weight of the liver and pancreas showed sexual dimorphism in cases where male and female data were available for direct comparison.

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

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.

Susceptibility of fungi isolated from the respiratory tract of falcons to amphotericin B, itraconazole and voriconazole

The minimum inhibitory concentrations (mics) of fungi isolated from the air sacs of falcons before (group 1), and during antifungal treatment with amphotericin B nebulisation and oral itraconazole or voriconazole (group 2), or with itraconazole alone (group 3) or voriconazole alone (group 4) were determined. Before treatment, 95 per cent of the isolates, including Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus terreus, were susceptible to voriconazole at mics up to 0·38 μg/ml, and all the isolates were susceptible at mics up to 1μg/ml. Before treatment, 21 per cent of the isolates, including A fumigatus (27·6 per cent), A flavus (16·6 per cent), A niger (100 per cent) and A terreus (23 per cent), were resistant (mic≥1 μg/ml) to itraconazole; 51 per cent of the isolates, including A fumigatus (31 per cent), A flavus (78 per cent), A niger (14 per cent) and A terreus (77 per cent), had mics of over 1 μg/ml to amphotericin B, and after treatment their mics increased significantly. In contrast, there were no significant differences between the mics of voriconazole and itraconazole for the different Aspergillus species before and during treatment with these antifungal agents.

Assessment of a commercial sandwich ELISA in the diagnosis of aspergillosis in falcons

A commercial sandwich ELISA (Platelia Aspergillus EIA; Bio-Rad) developed for the detection of galactomannan, a major cell wall constituent of Aspergillus species, was tested for its efficacy in the diagnosis of aspergillosis in falcons. Ninety serum samples from 50 aspergillosis-positive falcons and 182 samples from 142 aspergillosis-negative falcons were tested. The sensitivity of the test was only 12 per cent and its specificity was 95 per cent. The test was therefore unsatisfactory for detecting galactomannan in the serum samples and cannot be used as a screening test for aspergillosis in falcons.

Causes of morbidity in bustards in the United Arab Emirates.

The findings of 1746 clinical examinations of 594 bustards of six different species are presented, and the differences of causes of morbidity between imported adult, captive adult, and captive juvenile bustards are discussed. Wing tip trauma, keel trauma, and other soft tissue-related traumatic injuries were the most commonly diagnosed clinical conditions in captive adult bustards, accounting for 50.7% of the total findings in this category. Soft tissue-related related traumatic injuries accounted for 26.3% and 5.3% of the findings of imported adult and captive juvenile bustards, respectively. Musculoskeletal disorders were the most commonly diagnosed clinical conditions in captive juvenile bustards, accounting for 61.3% of the total findings in this category. Nutritional bone disease was the single most important musculoskeletal disorder in captive juvenile bustards, accounting for 24% of total findings. Musculoskeletal disorders accounted for 22.9% and 4.9% of findings in captive adult and imported adult bustards, respectively. Parasitic observations accounted for 24.7% of the total findings in imported adult bustards. Infectious viral diseases were almost exclusively confined to the imported adult bustards, making up 20.1% of findings in this group. Opthalmologic conditions accounted for 15.1% of findings in imported adult bustards.

Bacterial flora of the conjunctiva and nasal cavity in normal and diseased captive bustards.

A survey was carried out to describe the normal aerobic bacterial flora of the conjunctiva and nasal cavity of captive houbara bustards (Chlamydotis undulata), kori bustards (Ardeotis kori), and white-bellied bustards (Eupodotis senegalensis) maintained at the National Avian Research Center, Abu Dhabi, United Arab Emirates. A total of 58 samples were examined from the nasal cavity and 55 samples from the conjunctiva of healthy bustards. There was no bacterial growth in 45% of conjunctival samples. Bacteria isolated from the conjunctiva of healthy birds included Micrococcus spp., Staphylococcus auricularis, Staphylococcus xylosus, Staphylococcus capitis, Staphylococcus warneri, Bacillus spp., and Enterobacter amigenus. Bacteria isolated from the nasal cavity of healthy birds included Bacillus spp., Micrococcus spp., S. auricularis, S. xylosus, Staphylococcus simulans, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus cohnii, Staphylococcus sciuri, Aerococcus spp., and Providencia rettgeri. These findings were compared with bacterial isolates from bustards with clinical signs of ocular or upper respiratory tract diseases. Mycoplasma spp., Pseudomonas aeruginosa, Pseudomonas stutzeri, Proteus mirabilis, Escherichia coli, Klebsiella spp., Aeromonas hydrophila, and Staphylococcus aureus were the pathogenic bacteria isolated from the conjunctiva of 34.3% bustards with ocular discharges. Mycoplasma spp., P. aeruginosa, Pseudomonas spp., P. mirabilis, E. coli, Klebsiella pneumoniae, and S. aureus were the pathogenic bacteria isolated from the nasal cavity of 74% bustards with upper respiratory tract diseases.

Plasma concentrations of voriconazole in falcons

Doses of 12·5 mg voriconazole/kg bodyweight administered every 12 hours by crop gavage to six falcons for 14 days provided peak plasma concentrations of more than 1 μg/ml, but the trough concentrations were lower and sometimes undetectable. Administering the same doses incorporated into meat that was fed to one falcon for seven days and to three falcons for up to 91 days provided similar plasma concentrations.

Postmortem findings in bustards in the United Arab Emirates

A review was conducted of 236 postmortem examinations of six species of captive and imported bustards in the United Arab Emirates for the period 1979-94. The most common causes of death in adult imported houbara bustards (Chlamydotis undulata macqueenii) were euthanasia due to Newcastle disease, aspergillosis, and post-transportation-related deaths. Helminth parasites were a common finding in imported houbara bustards, and large parasite burdens occasionally caused intestinal obstruction and death. The most common causes of death in adult captive houbara bustards were trauma-related deaths and euthanasia for or death following treatment for capture myopathy. Fatty liver change was an important postmortem finding of captive adult houbara bustards. The main cause of death in juvenile houbara bustards was yolk-sac infection and septicemia. The most common causes of death in adult kori bustards (Ardeotis kori) were capture myopathy and handling injuries or euthanasia following these injuries. The most common causes of death in adult rufouscrested bustards (Eupodotis ruficrista) were post-transportation deaths in imported birds and trichomoniasis and trauma in captive birds. Juvenile rufous-crested bustards appeared to be highly susceptible to gizzard impactions and foreign-body obstructions of the gastrointestinal tract. Nutritional bone disease is an important disease of all juvenile bustards, particularly kori and houbara bustards. Aspergillosis was also a common postmortem finding in captive and imported adult houbara bustards and also caused mortality in juvenile kori and houbara bustards.

An outbreak of cryptosporidiosis in a collection of Stone curlews (Burhinus oedicnemus) in Dubai.

We describe an outbreak of cryptosporidiosis in Stone curlews kept in a mixed-species rearing unit in Dubai. Cryptosporidium was the predominant intestinal pathogen detected, although microbiological investigations revealed a concurrent Salmonella infantis infection in two of the 29 Stone curlew chicks that died. Nineteen of 29 birds had catarrhal enteritis associated with histopathological findings of numerous Cryptosporidium developmental stages at the mucosal surface. Catarrhal enteritis was present without associated Cryptosporidium oocysts in five cases. Histology of the intestine, faecal examination by direct microscopy and antigenic detection by immunochromatography revealed the presence of Cryptosporidium spp. associated with catarrhal enteritis in intestinal sections and faeces. Clinical and histopathological outcomes of infection were severe, including disruption of intestinal epithelial integrity, the presence of numerous endogenous Cryptosporidium stages in intestinal epithelia and the excretion of large numbers of sporulated oocysts. The application of polymerase chain reaction and restriction fragment length polymorphism techniques at two 18S rRNA and one Cryptosporidium oocyst wall protein gene locus confirmed the presence of Cryptosporidium parvum DNA in faecal samples.

AGE-RELATED HEMATOLOGIC CHANGES IN CAPTIVE-REARED HOUBARA, WHITE-BELLIED, AND RUFOUS-CRESTED BUSTARDS

Blood samples were obtained at monthly intervals between April 1994 and March 1996 from captive-bred houbara (Chlamydotis undulata macqueenii), rufous-crested (Eupodotis ruficrista gindiana), and white-bellied (Eupodotis senegalensis) bustards from 4–24 wk of age. Hematology investigations were conducted to determine age-related changes and to establish reference values for growing chicks of these species. There were significant age-related changes in hematocrit, hemoglobin, and red cell count in young birds compared with those of adults. White cell counts (lymphocytes and monocytes) were higher in juvenile birds, compared with adult values.