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OBJECTIVE To compare ketamine-butorphanol-azaperone-medetomidine (KBAM) to detomidine-etorphine-acepromazine (DEA) for field anesthesia in captive Przewalski horses (Equus przewalskii). ANIMALS 10 adult Przewalski horses. PROCEDURES A prospective randomized crossover trial was conducted. Each horse was immobilized once with KBAM (200 mg ketamine, 109.2 mg butorphanol, 36.4 mg azaperone, and 43.6 mg medetomidine) and once with DEA (40 mg detomidine premedication, followed 20 minutes later by 3.9 to 4.4 mg etorphine and 16 to 18 mg acepromazine). Both protocols were administered by IM remote dart injection with a washout period of 6 months between treatments. Selected cardiorespiratory variables and quality of anesthesia were recorded. Antagonists were administered IM (KBAM, 215 mg atipamezole and 50 mg naltrexone; DEA, 4 mg RX821002 and 100 mg naltrexone). RESULTS All horses were anesthetized and recovered uneventfully. Inductions (DEA, 6.8 min; KBAM, 11.6 min; P = 0.04) and recoveries (DEA, 3.2 min; KBAM, 19.6 min; P < 0.01) were faster with DEA compared with KBAM. Quality scores for induction and recovery did not differ between protocols, but maintenance quality was poorer for DEA (P < 0.01). Clinical concerns during DEA immobilizations included apnea, severe hypoxemia (arterial partial pressure of oxygen < 60 mm Hg), muscle rigidity, and tremors. Horses treated with KBAM were moderately hypoxemic, but arterial partial pressures of oxygen were higher compared with DEA (P < 0.01). CLINICAL RELEVANCE Captive Przewalski horses are effectively immobilized with KBAM, and this protocol results in superior muscle relaxation and less marked hypoxemia during the maintenance phase, but slower inductions and recoveries, compared with DEA.

Cervid babesiosis, caused by the protozoan hemoparasite Babesia odocoilei and transmitted by the blacklegged tick Ixodes scapularis, is an emerging disease of Canadian cervids. This pathogen has not yet been described in humans. Data are lacking on the role of migratory birds in the adventitious spread of Ba. odocoilei-infected ticks, as well as on the infection status of I. scapularis in environments used by susceptible wildlife hosts. Following a high-mortality outbreak of cervid babesiosis at the Toronto Zoo [TZ], the present study was initiated to investigate Ba. odocoilei and other tick-borne pathogens of veterinary and public health importance (Borrelia burgdorferi sensu stricto (s.s.), Anaplasma phagocytophilum, Borrelia miyamotoi, and Babesia microti) in I. scapularis at three sites in southern Ontario, Canada. Blanket dragging for questing ticks yielded I. scapularis from the three sites evaluated: TZ, Point Pelee National Park, and Long Point Bird Observatory [LPBO]. Babesia odocoilei was identified in I. scapularis collected by dragging at the TZ and at LPBO. Borrelia burgdorferi s.s. was identified in I. scapularis at all three sites. Anaplasma phagocytophilum was identified in I. scapularis collected from the TZ. During the springs of 2016 and 2017, 1102 northward-migrating birds were examined for ticks at LPBO. One or more I. scapularis were found on 3.2% of birds (n = 595) in 2016, and 6.7% (n = 507) of birds in 2017. Overall, across both years, 0.2% and 0.5% of birds carried one or more I. scapularis ticks that tested PCR-positive for Ba. odocoilei and Bo. burgdorferi s.s., respectively. These data indicate that Ba. odocoilei-positive I. scapularis are found in southern Ontario, and suggest that bird-borne ticks have the potential to contribute to range expansion of both Ba. odocoilei and Bo. burgdorferi s.s. in Canada.

Mycobacteriosis was implicated in the deaths of eight Chinese gliding frogs (Rhacophorus dennysi) in a zoo population over a 3 yr period. Clinical signs included nonhealing skin lesions, cloacal prolapse, hind limb weakness, weight loss, and sudden death. Abnormalities on postmortem were proliferative or ulcerative skin lesions in four of eight, pneumonia in three of eight, and gall bladder empyema in two of eight cases. All eight clinical cases had multisystemic granulomas containing acid-fast bacilli. Tissues most commonly affected were lung (seven of eight), liver (six of eight), kidney (six of eight), spleen (five of eight), and heart (five of eight). The remaining eight clinically normal frogs in the population were euthanized: eight of eight had granulomatous lesions, with acid-fast bacilli in three of eight cases. A mycobacterial species was cultured from four of the clinical cases by the Public Health Ontario Laboratory and was initially misidentified as Mycobacterium tuberculosis complex by a commercial line-probe assay (GenoType Mycobacterium CM, Hain Lifesciences, Nehren, Germany). Further diagnostic testing using 16S rRNA gene sequencing ultimately identified the mycobacterial species as Mycobacterium marinum. The correct identification of mycobacterial species is essential in epidemiological investigations at zoological facilities, and in assessing health risks to staff and to other animals in the zoo population.

A 23-yr-old captive-born Przewalski's horse mare (Equus przewalskii) was euthanized at a Canadian zoo because of severe colic resulting from rupture of a jejunal pseudodiverticulum. An incidental finding of an encysted larval cestode within a hepatic granuloma was diagnosed on histopathology. Gel-based polymerase chain reaction (PCR) on liver tissue was positive for Echinococcus granulosus sensu lato, and deoxyribonucleic acid sequencing of the PCR product was 100% homologous with Echinococcus equinus. This appears to be the first molecular confirmation of E. equinus in North America, and the first report of cystic echinococcosis in a Przewalski's horse.

The endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been held and bred in zoos for release into protected areas in Puerto Rico since 1982. In 2004, several cases of a novel syndrome of skin changes in toads were noticed at the Toronto Zoo. A total of 21 toads were found to have similar lesions and the condition has been seen in several other groups of toads in subsequent years. Affected toads show an uncharacteristic sheen of dark-brown leathery skin, followed by recurring dysecdysis, reduced appetite, weight loss, and death from secondary causes. Histologically the condition is characterized by epithelial hyperplasia and hyperkeratosis, ulceration, and the presence of superficial mats of bacterial and fungal agents. No etiology has been identified and to date toads have not permanently responded to treatment with various pharmaceutical and nutritional therapies.

The objective of this study was to evaluate if extraction of broken feathers outside the molting period was an efficient method to induce growth of new flight feathers as part of the rehabilitation process of raptors with damaged plumage. Primaries, secondaries, and rectrices (four of each) were removed under general anesthesia from 10 American kestrels (Falco sparverius) using two different protocols: with and without filling the follicle with bismuth subnitrate (Orbeseal) to prevent it from sealing. Birds were kept in large aviaries under natural daylight and outdoor temperatures. Rate and quality of growth of new feathers were assessed regularly for 4 mo. Results were significantly different between the types of feathers: 100% of rectrices, 58% of secondaries, and 8% of primaries started to grow within the 4 winter months, and 95% of rectrices, 30% of secondaries, and 0% of primaries completed their growth normally within this period. The use of Orbeseal did not improve the outcome. The tail feathers began to grow between the second and third weeks at about 2.7 mm/day, and growth was completed within 7 wk. Rate, starting time, and duration of remigial growth were less predictable and varied widely among individuals. Although the exact impact of these extractions on the natural molt is still unclear, most of the primaries that were plucked during this study failed to regrow normally during the following molt. In conclusion, plucking damaged tail feathers in kestrels can successfully decrease the duration of rehabilitation. However, this procedure would not be recommended for wing feathers.

Babesia odocoilei, a tick-borne protozoan hemoparasite of white-tailed deer ( Odocoileus virginianus), is being increasingly recognized as a cause of disease in captive cervids in North America. Historically endemic in white-tailed deer, the natural wildlife reservoir in the southeastern US, B. odocoilei has been recently associated with hemolytic anemia in captive Eurasian tundra reindeer ( Rangifer tarandus tarandus), wapiti ( Cervus canadensis), and woodland caribou ( Rangifer tarandus caribou) in the northcentral and northeastern US and several Canadian provinces. The emergence of B. odocoilei is likely related to the northward expansion of the range of the tick vector, Ixodes scapularis, and possibly to cervid translocations. Following a disease outbreak in reindeer and wapiti at the Toronto Zoo in Ontario, Canada, we utilized a prospective postmortem survey to investigate the prevalence of B. odocoilei in wild, farmed, and zoo cervids in Ontario ( n=270) in 2016-18 by PCR and DNA sequencing of spleen samples. Zoo bovids have been suggested as potential hosts of B. odocoilei in zoos affected by cervid babesiosis, so we also collected postmortem samples from five species of bovids ( n=7) at the Toronto Zoo that died or were euthanized during this time. We detected B. odocoilei in 1% (2/142) of farmed red deer ( Cervus elaphus) as well as in 3% (1/29) of captive wapiti and 4% (3/68) of wild white-tailed deer. Tissues from all zoo bovids and caribou, zoo and wild moose ( Alces alces), and farmed white-tailed deer, wapiti-red deer hybrids, and fallow deer ( Dama dama), tested negative for B. odocoilei. No clinical cases of babesiosis were encountered during this study. These findings suggest that white-tailed deer are a potential natural wildlife reservoir for B. odocoilei in Ontario and that red deer and wapiti could serve as more-localized reservoirs.

Avian bornavirus (ABV), the cause of proventricular dilation disease in psittacine birds, has been detected in multiple tissues of infected birds using immunohistochemical staining (IHC) and reverse transcription polymerase chain reaction (RT-PCR). In the current study, real-time RT-PCR, using primers targeting the ABV matrix gene, was used to detect ABV in 146 tissues from 7 ABV-infected psittacine birds. Eighty-six percent of the samples tested positive, with crossing point values ranging from 13.82 to 37.82 and a mean of 22.3. These results were compared to the findings of a previous study using gel-based RT-PCR and IHC on the same samples. The agreement between the 2 RT-PCR techniques was 91%; when tests disagreed it was because samples were negative using gel-based RT-PCR but positive on real-time RT-PCR. Agreement with IHC was 77%; 16 out of 74 samples were negative using IHC but positive on real-time RT-PCR. The results suggest that real-time RT-PCR is a more sensitive technique than gel-based RT-PCR and IHC to detect ABV in tissues. The tissues that were ranked most frequently as having a high amount of viral RNA were proventriculus, kidney, colon, cerebrum, and cerebellum. Skeletal muscle, on the other hand, was found to have a consistently low amount of viral RNA.

Nine hundred and fifty-five pathology cases collected in Ontario between 1992 and 2011 from wild free-ranging Canada geese, trumpeter swans and mute swans were retrospectively evaluated for the pathology associated with avian bornavirus (ABV) infection. Cases were selected based on the presence of upper gastrointestinal impaction, central nervous system histopathology or clinical history suggestive of ABV infection. The proportion of birds meeting at least one of these criteria was significantly higher at the Toronto Zoo (30/132) than elsewhere in Ontario (21/823). Central, peripheral and autonomic nervous tissues were examined for the presence of lymphocytes and plasma cells on histopathology. The presence of virus was assessed by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) on frozen brains and on formalin-fixed paraffin-embedded tissues. Among selected cases, 86.3% (44/51) were considered positive on histopathology, 56.8% (29/51) were positive by immunohistochemistry, and RT-PCR was positive on 88.2% (15/17) of the frozen brains and 78.4% (40/51) of the formalin-fixed paraffin-embedded samples. Histopathological lesions included gliosis and lymphoplasmacytic perivascular cuffing in brain (97.7%), spinal cord (50%), peripheral nerves (55.5%) and myenteric ganglia or nerves (62.8%), resembling lesions described in parrots affected with proventricular dilatation disease. Partial amino acid sequences of the nucleocapsid gene from seven geese were 100% identical amongst themselves and 98.1 to 100% identical to the waterfowl sequences recently described in the USA. Although ABV has been identified in apparently healthy geese, our study confirmed that ABV can also be associated with significant disease in wild waterfowl species.

To investigate the possibility of in ovo infection with avian bornavirus (ABV) in wild Canada geese (Branta canadensis), 53 eggs were opportunistically collected at various stages of embryonic development from 16 free-ranging goose nests at a large urban zoo site where ABV infection is known to be present in this species. ABV RNA was detected in the yolk of one of three unembryonated eggs using real-time reverse transcription polymerase chain reaction. ABV RNA was not identified in the brains from 23 newly hatched goslings or 19 embryos, nor from three early whole embryos. Antibodies against ABV were not detected in the plasma of any of the hatched goslings using an enzyme-linked immunosorbent assay. Possible reasons for the failure to detect ABV RNA in hatchlings or embryos include low sample size, eggs deriving from parents not actively infected with ABV, the testing of only brain tissue, and failure of the virus to replicate in Canada goose embryos. In conclusion, this preliminary investigation demonstrating the presence of ABV RNA in the yolk of a Canada goose egg provides the first evidence for the potential for vertical transmission of ABV in waterfowl.

The endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been held and bred in zoos for release into protected areas in Puerto Rico since 1982. In 2004, several cases of a novel syndrome of skin changes in toads were noticed at the Toronto Zoo. A total of 21 toads were found to have similar lesions and the condition has been seen in several other groups of toads in subsequent years. Affected toads show an uncharacteristic sheen of dark-brown leathery skin, followed by recurring dysecdysis, reduced appetite, weight loss, and death from secondary causes. Histologically the condition is characterized by epithelial hyperplasia and hyperkeratosis, ulceration, and the presence of superficial mats of bacterial and fungal agents. No etiology has been identified and to date toads have not permanently responded to treatment with various pharmaceutical and nutritional therapies.