Risk Assessment of Human Consumption of Meat From Fenbendazole-Treated Pheasants.

Fenbendazole is a benzimidazole-class anthelmintic that is used for the control of immature and adult stages of internal parasites, such as nematodes and trematodes, in domestic food-animal species. It is not approved by the United States Food and Drug Administration for treating pheasants despite Syngamus trachea being one of the most prevalent nematodes that parasitize pheasants. Because it is a highly effective treatment, e.g., 90% effectiveness against S. trachea, and there are very few alternative therapeutic options, this anthelminthic is used in an extra-label manner in the pheasant industry, but few studies have been conducted assessing risks to humans. Therefore, we conducted a risk assessment to evaluate the potential repeat-dose and reproductive, teratogenic, and carcinogenic human risks that may be associated with the consumption of tissues from pheasants that were previously treated with fenbendazole. We conducted a quantitative risk assessment applying both deterministic and stochastic approaches using different fenbendazole sulfone residue limits (tolerance, maximum residue limits, and analytical limit of detection) established in different poultry species by the Food and Drug Administration, the European Medicines Agency, and other regulatory agencies in Japan, Turkey, and New Zealand. Our results show that fenbendazole poses minimal risk to humans when administered to pheasants in an extra-label manner, and a comparison of different fenbendazole sulfone residue limits can help assess how conservative the withdrawal interval should be after extra-label drug use.

TaqMan quantitative real-time PCR for detecting Avipoxvirus DNA in various sample types from hummingbirds.

BACKGROUND: Avian pox is a viral disease documented in a wide range of bird species. Disease-related detrimental effects can cause dyspnea and dysphagia, and birds with high metabolic requirements, such as hummingbirds, are thus especially vulnerable to the pathogen. Hummingbirds have a strong presence in California, especially in urban environments. However, little is understood regarding the impact of pox virus on hummingbird populations. Currently, diagnosing a pox infection relies on obtaining a tissue biopsy, which poses significant risks to birds and challenges in the field. Understanding the ecology of hummingbird pox viral infections could be advanced by a minimally invasive ante-mortem diagnostic method. Our aim was to address whether pox infections can be diagnosed using integumentary system samples besides tissue biopsies. To meet this goal, we tested multiple integumentary sample types using a quantitative real-time PCR assay. A secondary study goal was to determine which sample types (ranging from minimally to highly invasive sampling) were optimal for identifying infected birds. METHODOLOGY AND PRINCIPAL FINDINGS: Pox-like lesion tissue, pectoral muscle, feathers, toenail clippings, blood, and swabs (both pox-like lesion tissue and non pox-like lesion tissue) were taken from live birds and carcasses of two species of hummingbirds found in California. To maximize successful diagnosis, especially for samples with low viral load, a real-time quantitative PCR assay was developed for detecting the hummingbird-specific Avipoxvirus 4b core protein gene. Avipoxvirus DNA was successfully amplified from all sample types obtained from 27 individuals. These results were compared to those of conventional PCR and comparisons were also made among sample types, utilizing lesion tissue samples as the gold standard. CONCLUSIONS AND SIGNIFICANCE: Hummingbird avian pox can be diagnosed without relying on tissue biopsies. We identify that feather samples, of which contour feathers yielded the best results, can be used for diagnosing infected birds, thus reducing sampling risk. In sum, the real-time PCR assay detected viral DNA in various integumentary system sample types and will be useful in future studies of hummingbird disease ecology.

HISTOPATHOLOGIC FINDINGS IN FREE-RANGING CALIFORNIA HUMMINGBIRDS, 1996-2017.

A histopathologic study of free-ranging hummingbirds found in California, US was performed to identify mortality trends. Tissues from 61 wild hummingbirds representing five native California species collected by the San Diego Zoo from 1996 to 2016 or the Lindsay Wildlife Experience from 2015 to 2017 were histologically examined. Birds were either found dead or moribund at the time of submission or were euthanized due to unresolvable health issues. Long-term rehabilitated birds were excluded from this study. Lesions were sorted by organ, etiology, and gender. The most commonly affected organs were the lung (68%, 40/59), followed by the ingluvies (67%, 34/51) and the liver (54%, 33/61). While some birds had minimal or nonspecific lesions, 23% (14/61) had lesions primarily attributable to trauma, 16% (10/61) had lesions associated with bacteria, fungi, or viruses, 11% (7/61) had parasitic lesions, and 13% (8/61) had multifactorial concurrent processes. Infectious disease lesions included those associated with avian poxvirus, intestinal adenovirus, disseminated aspergillosis, bacterial septicemia, malaria ( Haemoproteus spp.), and mycobacteriosis. The most commonly identified parasitic infection was intestinal cestodiasis, for which there was no significant associated intestinal damage, although the large size of these cestodes may have affected digestion. The incidence of traumatic lesions did not vary significantly by sex, age, species, or sampling location. Other significant findings not related to disease or trauma, but not previously documented, were histologic evidence of a gallbladder and the presence of aortic ossification. Our study reported mortality trends at a population level for free-ranging hummingbirds found in California and identified the presence of intestinal adenovirus and two anatomic structures not previously described.

Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in red-tailed hawks (Buteo jamaicensis).

OBJECTIVE: To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis). ANIMALS: 7 adult nonreleasable healthy red-tailed hawks. PROCEDURES: In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed. RESULTS: Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 µg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 µg/mL and target plasma ceftiofur concentration of 4 µg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.

Skin diseases in pet rabbits: a retrospective study of 334 cases seen at the University of California at Davis, USA (1984-2004).

BACKGROUND: Rabbits are growing in popularity as companion animals, and dermatology problems are often the presenting complaint when seeing a veterinarian. HYPOTHESIS/OBJECTIVES: To document skin diseases and their prevalence in pet domestic rabbits (Oryctolagus cuniculus) in northern California, USA; to investigate predilections for breed, age or sex for the most common conditions over a 20 year period. ANIMALS: Three hundred and thirty-four pet rabbits from the overall hospital population met inclusion criteria. METHODS: A retrospective study was carried out by searching the computerized medical records of rabbits seen at the Veterinary Medical Teaching Hospital (VMTH) from 1 January 1984 to 31 December 2004 using key words relevant to dermatology. RESULTS: Twenty-nine per cent of pet rabbits seen at the VMTH had skin disease. Lop-eared rabbits were over-represented, whereas mixed-breed rabbits and castrated males were under-represented in the dermatology caseload compared with the hospital population. Pododermatitis was the most common skin disease; abscesses, alopecia, otitis externa and ectoparasites also were common. Several species of bacteria other than Pasteurella spp. were isolated from abscesses. Despite the frequent mention of myxomatosis and venereal spirochetosis in the rabbit literature, few cases (three and two, respectively) were diagnosed. Castrated males were 3.7 times more likely to present with alopecia than intact males; rabbits <1 year of age were 3.6 times more likely to present with Psoroptes infestation/otitis than adult rabbits. CONCLUSIONS AND CLINICAL IMPORTANCE: Cutaneous conditions in pet rabbits in the USA are common. Bacterial culture should be performed and antibiotic susceptibility determined in all rabbits with abscesses, particularly those not responding to typical anti-Pasteurella antibiotics.

Inflammatory markers following acute fuel oil exposure or bacterial lipopolysaccharide in mallard ducks (Anas platyrhynchos).

Adult mallard ducks (Anas platyrhynchos) were orally dosed with bunker C fuel oil for 5 days, and five different inflammatory markers (haptoglobin, mannan-binding lectin, ceruloplasmin, unsaturated iron-binding capacity, and plasma iron) were measured in blood plasma prior to and 8, 24, 48, and 72 hr following exposure. In order to contrast the response to fuel oil with that of a systemic inflammatory response, an additional five ducks were injected intramuscularly with bacterial lipopolysaccharide (LPS). Oil-treated birds had an inflammatory marker profile that was significantly different from control and LPS-treated birds, showing decreases in mannan-binding lectin-dependent hemolysis and unsaturated iron-binding capacity, but no changes in any of the other inflammatory markers. Birds treated with oil also exhibited increased liver weights, decreased body and splenic weights, and decreased packed cell volume.

Dysgerminoma in an eastern rosella (Platycercus eximius eximius).

This report describes a case of dysgerminoma in a 21-year-old eastern rosella (Platycercus eximius eximius) that presented with dyspnea and a severely distended coelom. The bird was euthanatized, and a large, left-sided coelomic mass was identified. Microscopically, the mass was composed of sheets and nests of round to polygonal neoplastic cells with lacy cytoplasm. The neoplastic cells were weakly positive for vimentin and c-kit but negative for pancytokeratin, AE1, and inhibin. On the basis of the histomorphology and immunoreactivity, the neoplasm was determined to be a dysgerminoma. The variability of histologic appearance and immunohistochemical staining of dysgerminomas in humans compared with veterinary species is discussed.

Taenia coenurus in the orbit of a chinchilla.

A 4-year old, male intact, captive-bred chinchilla (Chinchilla lanigera) was presented due to progressive exophthalmos of the right eye over a 5-month period. Ophthalmic examination revealed exophthalmos with dorsal displacement of the right globe. Retropulsion was decreased and a fluctuant, subcutaneous mass could be palpated posterior and dorsal to the central aspect of the zygomatic bone. Transdermal ultrasonography revealed a fluid-filled mass consistent with a cyst located within the ventral right orbit. Computed tomography demonstrated dorsal displacement of the globe, lateral displacement of the zygomatic arch, and numerous mineral-dense foci within the lumen of the cyst. The cyst was removed en bloc by ventral transpalpebral orbitotomy. Histopathology revealed a single capsulated cyst with multiple invaginated protoscolices, characterized by a prominent scolex with refractile hooklets, suckers, and abundant calcareous corpuscles consistent with a Taenia coenurus. Exophthalmos resolved with surgical therapy and there was no evidence of recurrence or postoperative complications over a period of 2 years. To the authors' knowledge, this is the first reported case of an orbital cyst of parasitic origin in a chinchilla.

Assessment of a caudal external thoracic artery axial pattern flap for treatment of sternal cutaneous wounds in birds.

OBJECTIVE: To assess the use of a caudal external thoracic artery axial pattern flap to treat sternal cutaneous wounds in birds. ANIMALS: 16 adult Japanese quail. PROCEDURE: A cutaneous defect in the region of the mid-sternum was surgically created in all quail. In 6 quail (group I), an axial pattern flap was created from the skin of the lateral aspect of the thorax and advanced over the sternal defect. In 8 quail (group II), a flap was similarly created and advanced but the flap vasculature was ligated. All quail were euthanatized at 14 days after surgery and had necropsies performed. Sections of the flap and the surrounding tissue were examined histologically to assess flap viability. RESULTS: All axial pattern flaps in group-I quail had 100% survival. In group II, mean percentage area of flap survival was 62.5%; mean area of necrosis and dermal fibrosis of flaps were significantly greater than that detected in group I. In flaps of group-II quail, neovascularization in the deep dermis and profound necrosis of the vascular plexus in the superficial dermis were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the caudal external thoracic artery axial pattern flap could be used successfully in the treatment of surgically created sternal cutaneous defects in quail with no signs of tissue necrosis or adverse effects overall. Use of this technique to treat self-mutilation syndromes or application after surgical debulking of tumors or other masses might be beneficial in many avian species.

Cutaneous vascular malformation in a guinea pig (Cavia porcellus).

A skin lesion classified as a vascular malformation is reported in a young-adult, female guinea pig. The physical examination revealed a 3 x 2-cm irregularly shaped violaceous plaque located on the left caudal flank. The surface of the plaque was ulcerated and bled intermittently, resulting in fatal blood loss. On histology the mass consisted of variably sized vascular spaces filled with red blood cells and variable amounts of extramedullary haematopoietic cells, lined by well-differentiated endothelial cells often surrounded by one layer of spindle-shaped cells. Based on immunohistochemistry, the spindle cell population was confirmed to be smooth muscle cells and no proliferation of endothelial cells was found with the Ki67 proliferation marker. Histological and immunohistochemical findings were consistent with a vascular malformation. Classification of vascular malformations and potential treatments are discussed. To the authors' knowledge, this is the first reported case of a cutaneous vascular lesion in a guinea pig.

Adult cockatiels (Nymphicus hollandicus) at maintenance are more sensitive to diets containing excess vitamin A than to vitamin A-deficient diets.

The purpose of this experiment was to examine the physiological responses of adult cockatiels at maintenance to dietary vitamin A (VA) concentrations, and to identify concentrations associated with deficiency and toxicity. Adult cockatiels at maintenance (n = 22, 2-3 y of age) were fed a diet of 0, 600, 3000 or 30,000 microg VA/kg (0, 2000, 10,000 or 100,000 IU), and monitored for signs of VA deficiency or toxicity for up to 706 d. The analyzed diet concentrations were 0, 835, 2815 and 24,549 microg/kg, respectively. After 269 d, birds fed the 30,000 microg/kg VA diet had greater plasma retinal concentrations, markedly intensified vocalization patterns, pancreatitis and multifocal accumulation of lymphocytes in the lamina propria of the duodenum compared to birds fed the 600 microg/kg diet (P < 0.05). The 3000 microg/kg VA diet induced increased plasma retinol, splenic hemosiderosis and altered vocalization patterns (P < 0.05), although not as striking as those induced by the 30,000 microg/kg VA diet. The secondary antibody response was reduced after 225 d and vocalization patterns were altered in birds fed 0 microg/kg VA (P < 0.05), but after almost 2 y there were no changes in body condition, plasma retinol, organ pathology or classical signs of deficiency such as squamous metaplasia of nasal epithelia. Thus, adult cockatiels at maintenance were more susceptible to VA toxicity than to VA deficiency and concentrations > or = 3000 microg VA/kg diet can cause toxicity. It is possible that disturbances in VA nutrition contribute to the widespread incidence of behavioral problems reported in companion birds.

Internal papillomatosis with intrahepatic cholangiocarcinoma and gastrointestinal adenocarcinoma in a peach-fronted conure (Aratinga aurea).

A 17-yr-old pet female peach-fronted conure (Aratinga aurea) was presented with the chief complaints of mild lethargy and weight loss with increased appetite. Antemortem diagnostics included complete blood count, plasma biochemistry, and radiography. Abnormal findings included elevated inflammatory parameters (hyperfibrinogenemia) and a space-occupying mass in the region of the liver. Histologic examination of a liver biopsy sample indicated bile duct hyperplasia leading to a presumptive diagnosis of hepatoxicosis. The bird initially showed moderate improvement with supportive care, but its condition declined 9 days after the liver biopsy. Supportive care was attempted a second time, but the bird did not improve and euthanasia was elected. Abnormal gross necropsy findings were confined to the liver, which contained multiple tan nodules that exuded yellowish fluid on cut section. Histopathologic examination revealed multicentric bile duct hyperplasia and cholangiocarcinoma as well as segmental papillary hyperplasia and adenocarcinoma in the proventriculus, ventriculus, and throughout the intestinal tract. This is the first report of concurrent internal papillomatosis, gastrointestinal adenocarcinoma, and cholangiocarcinoma in a peach-fronted conure.