Assessing the extent and public health impact of bat predation by domestic animals using data from a rabies passive surveillance program.

Domestic animals can serve as consequential conveyors of zoonotic pathogens across wildlife-human interfaces. Still, there has been little study on how different domestic species and their behaviors influence the zoonotic risk to humans. In this study, we examined patterns of bat encounters with domestic animals that resulted in submission for testing at the rabies laboratories of the Canadian Food Inspection Agency (CFIA) during 2014-2020. Our goals were specifically to examine how the number of bats submitted and the number of rabies positive bats varied by the type of domestic animal exposure and whether domestic cats were indoor or free-roaming. The CFIA reported 6258 bat submissions for rabies testing, of which 41.5% and 8.7% had encounter histories with cats and dogs, respectively. A much smaller fraction of bat submissions (0.3%) had exposure to other domestic animals, and 49.5% had no domestic animal exposure. For the bat submissions related to cats, and where lifestyle was noted, 91.1% were associated with free-roaming cats and 8.9% with indoor cats. Model results indicated the probability of a rabies-positive bat was the highest with a history of dog association (20.2%), followed by bats with no animal exposure (16.7%), free-roaming cats (6.9%), cats with unspecified histories (6.0%) and the lowest probability associated with non-free-roaming (indoor) cats (3.8%). Although there was lower rabies prevalence in bats associated with cats compared to dogs, the 4.8 fold higher number of cat-bat interactions cumulatively leads to a greater overall rabies exposure risk to humans from any free-roaming outdoor cats. This study suggests that free-roaming owned cats may have an underappreciated role in cryptic rabies exposures in humans and as a significant predator of bats. Preventing free-roaming in cats is a cost-effective and underutilized public health recommendation for rabies prevention that also synergistically reduces the health burden of other feline-associated zoonotic diseases and promotes feline welfare and wildlife conservation.

INVESTIGATION OF SARCOCYSTIS SPP. INFECTION IN FREE-RANGING AMERICAN BLACK BEARS (URSUS AMERICANUS) AND GRIZZLY BEARS (URSUS ARCTOS HORRIBILIS) IN BRITISH COLUMBIA, CANADA.

Sarcocystis spp. are protozoan parasites that cause a spectrum of lesions in various hosts. Hepatic sarcocystosis and encephalitis have been described in captive American black bears (Ursus americanus) and polar bears (Ursus maritimus), and in a free-ranging grizzly bear (Ursus arctos horribilis), but have not previously been reported in free-ranging American black bears. This study aimed to characterize the presence and lesions associated with Sarcocystis spp. in free-ranging bears in British Columbia, Canada from samples submitted to the provincial diagnostic laboratory. From 2007 to 2019, 102 free-ranging American black bear and grizzly bear tissues were examined postmortem for sarcocystosis using histopathology and follow-up molecular diagnostics. Sarcocystosis was confirmed in 41 (40%) free-ranging bears including 39 American black bears and two grizzly bears. Microscopic lesions included multifocal necrotizing hepatitis, nonsuppurative encephalitis, and/or intramuscular sarcocysts with or without associated inflammation. Sarcocystosis was considered the cause of death in eight (20%) of these bears, exclusively in cubs of the year (<1 yr old). Sarcocystis canis was identified in 22/32 (69%) cases where molecular characterization was performed and was the etiologic agent associated with bears that died of sarcocystosis. Confirmed cases were distributed widely across British Columbia. While there was an alternate proximate cause of death in the other confirmed bears, sarcocystosis may have contributed. Age was a significant risk factor, with yearlings presenting more often with fulminant lesions; however, there was a sampling bias toward juvenile bear submissions due to size and ease of transport. Further research is needed to understand the disease epidemiology and significance to population health.

Pneumonia and gastritis in a cat caused by feline herpesvirus-1.

We report a case of fatal respiratory and gastric herpesvirus infection in a vaccinated, adult cat with no known immunosuppression or debilitation. The disease was characterized by severe necrotizing bronchopneumonia, fibrinonecrotic laryngotracheitis, and multifocal necrotizing gastritis associated with eosinophilic intranuclear inclusion bodies and a large amount of feline herpesvirus-1 antigen detected with immunohistochemistry.

Pneumonie et gastrite chez un chat causées par l'herpèsvirus-1 félin. Nous signalons un cas d'atteinte respiratoire et gastrique mortel causé par l'infection à l'herpèsvirus chez un chat adulte vacciné sans immunosuppression ni affaiblissement. La maladie a été caractérisée par une bronchopneumonie nécrosante grave, une laryngotrachéite fibrinonécrosante et une gastrite nécrosante multifocale associée à des corps d'inclusion intranucléaire acidophiles et une grande quantité d'antigènes de l'herpesvirus-1 félin détectée par analyse immunohistochimique.(Traduit par Isabelle Vallières).

Blindness in a wild American black bear cub (Ursus americanus).

An approximately six-month-old wild American black bear (Ursus americanus) was found wandering in Saskatchewan and was presented to the Veterinary Medical Centre of the Western College of Veterinary Medicine for apparent blindness. Clinical examination confirmed an inability to navigate a photopic maze, bilateral tapetal hyper-reflectivity, fundi devoid of retinal vessels, and small pale optic nerve papillae. Single-flash electroretinography revealed A and B-wave amplitudes of approximately 40 and 140 microvolts, respectively, in both eyes. Histologic abnormalities included bilateral optic papillary mineralization and bilateral segmental optic nerve degeneration, with occasional intralesional lymphocytes confirmed with immunohistochemistry for CD3+. There was also bilateral multifocal retinal dysplasia, gliosis, lymphocytic retinitis, a complete lack of retinal blood vessels, an intravitreal vascular membrane, and a mild lymphocytic-plasmacytic uveitis with small pre-iridal cellular membranes. The presence of a positive ERG in a blind bear with numerous retinal ganglion cells and degenerative changes in the optic nerve are most consistent with vision loss due to optic nerve injury, which given the young age of the bear likely occurred during ocular development. The presence of ocular inflammation suggests this injury resulted from an inflammatory/infectious process. The etiology could not be determined. Hepatic concentrations of vitamin A were within the normal reference range for domestic species. Pan-herpesvirus PCR and immunohistochemistry for canine distemper virus and Toxoplasma gondii were negative, although this does not rule out these or other infectious etiologies. This represents the first case report of neonatal or congenital ocular abnormalities in an ursid species.

Disease risks associated with free-ranging wild boar in Saskatchewan.

This study investigated the disease status of Saskatchewan's feral wild boar population. Whole carcasses, tissue samples, and/or serum from 81 hunter-killed boars from Saskatchewan were submitted to the Canadian Wildlife Health Cooperative (CWHC) between 2009 and 2014. Serological tests were negative for PRRS, H1N1, and H3N2 swine influenza, PCV-2, and TGE/PRCV in 22/22 boars and for Toxoplasma gondii and Mycoplasma hyopneumoniae in 20/20 boars. Of 20 boars whose sera were tested 20 were positive for Actinobacillus pleuropneumoniae, with 7 positive for, among other strains, serotype 14; 16 were positive for Lawsonia intracellularis, 1 was positive and 6 were suspicious for Salmonella spp. Polymerase chain reaction tests were negative for PRRS and PCV2 in 58/58 boars and positive for Torque teno virus in 1/8 boars. Digestion assays were negative for Trichinella spp. in 22/22 boars. The high seroprevalence of A. pleuropneumoniae serotype 14 is noteworthy as this serotype has not been previously reported in North America.

Risques de maladie associés au sanglier en liberté en Saskatchewan. Cette étude a examiné l'état des maladies de la population de sangliers féraux de la Saskatchewan. Des carcasses entières, des échantillons de tissus et/ou du sérum provenant de 81 sangliers tués par des chasseurs de la Saskatchewan ont été soumis à la Canadian Wildlife Health Cooperative (CWHC) entre 2009 et 2014. Les tests sérologiques étaient négatifs pour SRRP, l'influenza porcine H1N1 et H3N2, CVP-2 et GET/CVRP chez 22/22 sangliers et pour Toxoplasma gondii et Mycoplasma hyopneumoniae chez 20/20 sangliers. Parmi les 20 sangliers dont le sérum a été analysé, 20 présentaient des résultats positifs pour Actinobacillus pleuropneumoniae, et sept étaient positifs pour le sérotype 14, entre autres souches; 16 étaient positifs pour Lawsonia intracellularis, un était positif et six étaient suspectés pour Salmonella spp. Des tests d'amplification en chaîne par la polymérase ont été négatifs pour SRRP et CVP2 chez 58/58 sangliers et positifs pour le virus torque teno chez 1/8 des sangliers. Des épreuves de digestion ont été négatives pour Trichinella spp. chez 22/22 sangliers. La séroprévalence élevée du sérotype A. pleuropneumoniae 14 mérite d'être signalée car ce sérotype n'a pas été signalé antérieurement en Amérique du Nord.(Traduit par Isabelle Vallières).