Additional diagnoses of Echinococcus multilocularis in eastern chipmunks (Tamias striatus) from southern Ontario - results from ongoing surveillance for E. multilocularis in intermediate hosts in Ontario, Canada.

Echinococcus multilocularis, a cestode with zoonotic potential, is now known to have a high prevalence in wild canid definitive hosts of southern Ontario. The distribution of E. multilocularis across this region in red foxes (Vulpes vulpes) and coyotes (Canis latrans) is widespread yet heterogenous. In contrast, confirmed diagnoses of E. multilocularis in wild free-ranging intermediate hosts within Ontario are currently limited to a single eastern chipmunk (Tamias striatus). These findings prompted ongoing surveillance efforts in intermediate host species, primarily rodents. Our report describes the results of passive surveillance through wildlife carcass submissions to the Canadian Wildlife Health Cooperative (CWHC) and targeted active sampling of small mammal species from 2018 to 2023; a second and third eastern chipmunk were found to be infected with E. multilocularis. However, these were the only occurrences from surveillance efforts which collectively totaled 510 rodents and other small mammals. Continued surveillance for E. multilocularis in intermediate hosts is of high importance in light of the recent emergence of this parasite in Ontario.

Effects of inflammatory stimuli on responses of macrophages to Mycoplasma bovis infection.

Inflammation in the respiratory tract is thought to worsen the disease response to Mycoplasma bovis infection. This study investigated the cells involved in this response with a focus on proteases and cytokines as harmful effector mechanisms. By immunohistochemistry, Mac387-positive macrophages were the main cell type comprising the foci of caseous necrosis in cattle with M. bovis pneumonia. Thus, the study evaluated how priming of different types of macrophages with bacterial lysate (or pro-inflammatory cytokines induced by the bacterial lysate) affected their responses to M. bovis infection. Inducible responses were detected in monocyte-derived macrophages (M1-MDMs and M2-MDMs), whereas pulmonary alveolar macrophages (PAMs) were minimally affected by priming or infection. M. bovis-infected MDMs secreted MMP-12 and SPLA2, and priming with pro-inflammatory cytokines increased the secretion of cathepsin B in response to M. bovis infection. Of these, there were higher concentrations of cathepsin B and SPLA2 in lungs with M. bovis pneumonia compared to healthy lungs, and these are potential mechanisms for macrophage-induced lung damage in M. bovis infection. Priming of MDMs with either bacterial lysate or with pro-inflammatory cytokines caused an enhanced response to M. bovis infection with respect to IL-8 and IL-1ß secretion. The findings of this study suggest proteases, lipases and cytokines derived from monocyte-derived macrophages as possible mediators by which prior inflammation in the respiratory tract worsen disease outcomes from M. bovis infection.

HIGH PREVALENCE OF MYCOPLASMA AND EIMERIA SPECIES IN FREE-RANGING EASTERN WILD TURKEYS ( MELEAGRIS GALLOPAVO SILVESTRIS) IN ONTARIO, CANADA.

Following extirpation from Ontario, Canada in the early 1900s, Eastern Wild Turkeys (EWTs; Meleagris gallopavo silvestris) were successfully reintroduced to the province in 1984. Despite the subsequent establishment of robust populations and biannual hunting seasons, data on the circulation of potential pathogens in these birds are lacking. Similarly, the interface between EWTs and poultry is poorly understood and includes possible bidirectional pathogen transmission via direct or indirect contact. Mycoplasma and Eimeria spp. are potential pathogens in Galliformes, and our objective was to determine their prevalence and distribution in Ontario EWTs. During the 2015 spring hunting season (April and May), oropharyngeal swabs from 147 hunter-harvested and five opportunistically collected EWTs from southern Ontario were cultured for Mycoplasma spp. The intestinal or cloacal contents of 107 of these birds and an additional 24 opportunistically and biologist-collected EWTs were analyzed for Eimeria spp. using PCR or fecal flotation. At least one Mycoplasma spp. was isolated from 98.7% (150/152) of EWTs, with six species identified. Mycoplasma gallopavonis was identified most commonly in 96.7% (147/152), followed by Mycoplasma gallinaceum in 23.7% (36/152). Potential poultry pathogens ( Mycoplasma meleagridis, Mycoplasma iowae, and Mycoplasma synoviae) were isolated from swabs of five (3.3%) EWTs. Coinfections with up to three Mycoplasma spp. were detected in 36.8% (56/152) of EWTs. Most EWTs tested positive for Eimeria spp. oocysts (75.6%; 99/131). A subset of positive samples ( n=16) were characterized by PCR, which detected the following species: Eimeria meleagrimitis (93.8%), Eimeria adenoeides (93.8%), Eimeria gallopavonis (56.3%), and Eimeria meleagridis (12.5%). The majority (93.8%) of these samples were positive for more than one Eimeria spp. We showed that numerous, mostly nonpathogenic Mycoplasma and Eimeria spp. circulate in EWTs across southern Ontario, and this helped to establish baseline information for comparison with future surveillance and monitoring.

ECHINOCOCCUS EQUINUS HYDATID CYST IN THE LIVER OF A PRZEWALSKI'S HORSE ( EQUUS PRZEWALSKII) IN A CANADIAN ZOO.

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.

SYSTEMIC ENCEPHALITOZOONOSIS DUE TO ENCEPHALITOZOON CUNICULI STRAIN IV IN A VANCOUVER ISLAND MARMOT ( MARMOTA VANCOUVERENSIS).

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.

Echinococcus multilocularis in a wild free-living eastern chipmunk (Tamias striatus) in Southern Ontario: A case report and subsequent field study of wild small mammals.

Southern Ontario has recently been identified as a risk area for Echinococcus multilocularis, based on surveys of foxes (Vulpes vulpes) and coyotes (Canis latrans) which act as definitive hosts of the parasite. In this manuscript, we describe the first detection of E. multilocularis in an eastern chipmunk (Tamias striatus) in North America. This case, submitted to the Canadian Wildlife Health Cooperative (CWHC) in August 2016 as part of ongoing wildlife disease surveillance activities, represents the first report of alveolar echinococcosis in a wild, free living, intermediate host from southern Ontario, providing further evidence of an established sylvatic cycle of E. multilocularis in this region. The finding prompted a field investigation to identify additional cases of alveolar echinococcosis in small mammals in the summer of 2017. Echinococcus multilocularis was not detected in any of the 196 small mammals submitted to the CWHC from across southern Ontario or in any of the 43 small mammals trapped in the area where the infected chipmunk was found. However, given the suspected low prevalence and patchy distribution of E. multilocularis in small mammals, our negative results do not preclude the established presence of the parasite. This case emphasizes the importance of passive surveillance networks for monitoring new and emerging diseases in wildlife populations.

The emergence of a new strain of porcine circovirus-2 in Ontario and Quebec swine and its association with severe porcine circovirus associated disease--2004-2006.

In the late fall of 2004 more severe lesions of porcine circovirus-2 associated disease (PCVAD) than usual occurred during an outbreak of porcine circovirus-2 (PCV-2) infection in Ontario nursery and grower/finisher pigs. The lesions were of unprecedented severity and included diffuse bronchointerstitial pneumonia, granulomatous enteritis, vasculitis, interstitial nephritis, and new lesions of splenic infarction. Some affected herds had up to 50% mortality. The outbreak correlated with the sudden emergence of a variant PCV-2, with PCR restriction fragment length polymorphism (RFLP) type 321. Phylogenetic comparison of ORF2 sequences and full genome sequences showed the new variant to be different from the previously dominant RFLP type 422 viruses, and similar to viruses that had occurred in France and other European and Asian countries. A subsequent retrospective study showed a statistically significant increase in the frequency of histological lesions in lymph node, spleen, lung, small intestine, colon and kidney, for pigs spontaneously infected with RFLP type 321, compared with the older RFLP type 422 strain. Viral burden, based on IHC staining in lymph node, also showed a statistically significant increase in pigs infected with the newer variant RFLP type 321, compared with the older RFLP type 422 strain. This enhanced virulence in pigs infected with PCV-2 RFLP type 321 strain may be related to the genetic differences in this new strain of PCV-2. This virus is now the dominant strain of PCV-2 virus found in Ontario and Quebec swine.