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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.

In collaboration with the American College of Veterinary Pathologists

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.

Vancouver Island marmots (Marmota vancouverensis) have been managed in a captive-breeding program since 1997, as in situ conservation efforts were insufficient in raising the numbers of this critically endangered species. The success of captive-breeding programs centers on sustainable reproduction and survival of individuals once released into the wild. Captive-born Vancouver Island marmots released to the wild have lower survival rates than their wild-born counterparts; this difference may arise from compromised hibernation patterns or behaviors. Hibernation duration, body weight over the hibernation season, and reproductive success of captive Vancouver Island marmots were reviewed to assess the effect of these variables on each other. Data from a total of 1782 hibernations and 456 breeding attempts were compiled from 1997 to 2018. The number of winters spent in captivity, the origin of the marmot (captive-born or wild-born), the facility at which hibernation occurred, and the body weight all had a significant effect on hibernation length (all p < .001). Increased weight was associated with increased hibernation length by 0.4 ± 0.1 day/kg on average (p = .0015). Captive, wild-born marmots hibernated for significantly longer than their captive-born counterparts by about 21 ± 2 days (p < .001). The odds of successful breeding were significantly increased with increasing hibernation length by approximatively 20% for every 10 additional days of hibernation. This study provides information on the intrinsic relationship between body weight, reproduction, and hibernation in captive Vancouver Island marmots.

A 2-mo-old Vancouver Island marmot ( Marmota vancouverensis), housed at a quarantined breeding facility, presented for acute obtundation and vestibular ataxia. Physical examination revealed poor growth compared with littermates, poor nutritional condition, and mild dehydration. The animal's condition deteriorated over 24 hr, and it was euthanized following the development of generalized seizures. No gross abnormalities were observed upon postmortem evaluation. Histologic evaluation revealed severe, multifocal, granulomatous and lymphoplasmacytic meningoencephalomyelitis and interstitial nephritis, with intralesional, intracytoplasmic spore-filled, parasitophorous vacuoles and segmental, multi-organ, fibrinoid vasculitis (disseminated encephalitozoonosis). The etiologic agent was evident by hematoxylin and eosin and Gram-chromotrope stains, and confirmed as Encephalitozoon cuniculi by polymerase chain reaction on brain tissue. Sequencing of the internal transcribed spacer region of the rRNA gene showed 100% homology with E. cuniculi strain IV, which is a newly described genotype. This is the first report of encephalitozoonosis in this critically endangered species.

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 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.

We surveyed free-ranging Canada Geese (Branta canadensis), Trumpeter Swans (Cygnus buccinator), Mute Swans (Cygnus olor), and Mallards (Anas platyrhynchos) to estimate the prevalence of antibodies to avian bornavirus (ABV) and of cloacal shedding of ABV RNA in southern Ontario, Canada. Blood samples and cloacal swabs were collected from 206 free-ranging Canada Geese, 135 Trumpeter Swans, 75 Mute Swans, and 208 Mallards at 10 main capture sites between October 2010 and May 2012. Sera were assessed for antibodies against ABV by enzyme-linked immunosorbent assay and swabs were evaluated for ABV RNA using real-time reverse-transcription PCR. Serum antibodies were detected in birds from all four species and at each sampling site. Thirteen percent of the geese caught on the Toronto Zoo site shed ABV RNA in feces compared with 0% in geese sampled at three other locations. The proportions of shedders among Mute Swans, Trumpeter Swans, and Mallards were 9%, 0%, and 0%, respectively. Birds that were shedding viral RNA were more likely to have antibodies against ABV and to have higher antibody levels than those that were not, although many birds with antibodies were not shedding. We confirmed that exposure to, or infection with, ABV is widespread in asymptomatic free-ranging waterfowl in Canada; however, the correlation between cloacal shedding, presence of antibodies, and presence of disease is not fully understood.

Isospora greineri sp. n. and Isospora superbusi sp. n. are described from captive superb glossy starlings, Lamprotornis superbus, from the Toronto Zoo succumbing to visceral coccidiosis. Sequence data from nuclear 18S recombinant DNA (rDNA) and mitochondrial cytochrome c oxidase subunit I (COI) loci from sporulated oocysts and infected tissues (liver, lung, or spleen) demonstrated two distinct Isospora sp. genotypes that varied in their relative abundance. In the tissues of one affected bird, as well as its associated fecal sample, two distinct COI sequences (1.7 % divergence) and two distinct 18S rDNA sequences (0.6 % divergence) were found at almost the same abundance; in other specimens, one of the 18S and one of the COI sequences were less abundant than the other. In the tissues of some birds, only a single COI and single 18S sequence were present. In all cases, the same pair of 18S rDNA and COI sequences fluctuated in abundance in parallel, indicating that there were two distinct species present rather than one species with more than one COI or 18S locus. The oocysts of these new species cannot be differentiated morphologically. Sporulated oocysts of both were spherical to subspherical measuring 17.7 ± 0.22 μm by 17.1 ± 0.20 μm with a mean L/W ratio of 1.03 ± 0.004. Sporocysts were ovoid measuring 13.5 ± 0.17 μm by 9.3 ± 0.15 μm with a mean L/W ratio of 1.4 ± 0.02. Sporocysts had a small Stieda body with indistinct sub-Stieda body; each sporocyst had a compact residuum. Two morphologically similar but genetically divergent Isospora species were shown to cause simultaneous enteric and extraintestinal infections in captive superb glossy starlings.

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.

In 2008, avian bornaviruses (ABV) were identified as the cause of proventricular dilatation disease (PDD). PDD is a significant condition of captive parrots first identified in the late 1970s. ABV infection has subsequently been shown to be widespread in wild waterfowl across the United States and Canada where the virus infects 10–20% of some populations of ducks, geese and swans. In most cases birds appear to be healthy and unaffected by the presence of the virus; however, infection can also result in severe non-suppurative encephalitis and lesions similar to those seen in parrots with PDD. ABVs are genetically diverse with seven identified genotypes in parrots and one in canaries. A unique goose genotype (ABV-CG) predominates in waterfowl in Canada and the northern United States. ABV appears to be endemic in North American waterfowl, in comparison to what appears to be an emerging disease in parrots. It is not known whether ABV can spread between waterfowl and parrots. The discovery of ABV infection in North American waterfowl suggests that European waterfowl should be evaluated for the presence of ABV, and also as a possible reservoir species for Borna disease virus (BDV), a related neurotropic virus affecting horses and sheep in central Europe. Although investigations have suggested that BDV is likely derived from a wildlife reservoir, for which the shrew and water vole are currently prime candidates, we suggest that the existence of other mammalian and avian reservoirs should not be discounted.

AVIAN bornavirus (ABV), a newly discovered agent, has been identified as the causal agent of proventricular dilation disease (PDD) in psittacine birds (Honkavuori and others 2008, Kistler and others 2008). Subsequent research, including bird inoculation studies (Gancz and others 2009, Gray and others 2010) and outbreak investigations (Kistler and others 2010) have provided strong supporting evidence. PDD is a significant pathological syndrome, with high mortality affecting primarily psittacine birds, that has been reported worldwide since the late 1970s. Characteristic pathological findings of PDD …