The epidemiology of bovine tuberculosis (Mycobacterium bovis) in the Greater Riding Mountain Ecosystem

The overall objective of this thesis is to provide an enhanced understanding of the epidemiology of Mycobacterium bovis in the Greater Riding Mountain Ecosystem (GRME) and provide a scientific basis for disease management from a systems perspective now and into the future. M. bovis prevalence has been consistently higher in elk compared to white-tailed deer, and higher within a defined Core area compared to areas outside. Prevalence in both species declined significantly between 2003 and 2013. Only one infected elk was detected in 2013; the last infected white-tailed deer was detected in 2009 and the last infected cattle herd was detected in 2008. Parallel interpretation of three blood-based assays resulted in effective selective culling of elk within Riding Mountain National Park (RMNP) with predictive value negative of 100%. A lymphocyte stimulation test (LST) was the most sensitive single blood-based assay, but was difficult to perform under field conditions. Combinations of humoral antibody tests and cell-mediated tests performed better than any single test, likely detecting the broad spectrum of host pathology present. Seven of 14 risk factors were identified for wild cervids testing culture positive with the three being most strongly associated with culture positivity being geographical location (within core area), elk density and year category (sampling phase). Age, sex, and surveillance method were also significant factors, but species was not. A rapid decline in elk density in combination with fencing of hay storage yard and non-selective culling were likely key factors resulting in the M. bovis prevalence decline observed in elk, and an overall decline in prevalence from 1997 for both species. Elk were the primary reservoir species in this episystem, but are now considered a spillover host, while white-tailed deer have always been a spillover host due to lower densities and shorter life expectancy. Very limited strain diversity exists within the GRME with one spoligotype restricted to cattle and associated with a limited outbreak in five herds in the early 1990’s, and three other shared strains between cattle and wildlife. A single monomorphic type was present in white-tailed deer. Significant spatial overlap of wildlife and cattle isolates delineated a core area where management activities are now focused. The relative simplicity of this episystem has allowed significant progress on control and management to be achieved, despite being located within a national park. Wildlife surveillance will need to continue until at least 2022 in order to achieve a 95% probability of freedom using three different surveillance streams. Latent cases are likely to be extremely rare in future and unlikely to result in ongoing transmission as the factors that created this wildlife reservoir no longer exist. Wild cervids should not be considered ideal maintenance hosts for M. bovis in North America but rather facultative hosts; acting either as a reservoir or spillover host dependent on regional/local density and presence/absence of baiting and feeding

Lesion Distribution and Epidemiology of Mycobacterium bovis in Elk and White-Tailed Deer in South-Western Manitoba, Canada

Surveillance for Mycobacterium bovis in free-ranging elk (Cervus elaphus) and white-tailed deer (Odocoileus virginianus) from south-western Manitoba was carried out from 1997 to 2010 to describe the lesions, epidemiology, and geographic distribution of disease. Tissues were cultured from animals killed by hunters, culled for management, blood-tested, or found opportunistically. Period prevalence in elk was approximately six times higher than deer, suggesting a significant reservoir role for elk, but that infected deer may also be involved. Prevalence was consistently higher in elk compared to deer in a small core area and prevalence declines since 2003 are likely due to a combination of management factors instituted during that time. Older age classes and animals sampled from the core area were at significantly higher risk of being culture positive. Positive elk and deer were more likely to be found through blood testing, opportunistic surveillance, and culling compared to hunting. No non-lesioned, culture-positive elk were detected in this study compared to previous studies in red deer

Prevalence of Antibodies to Canine Parvovirus and Distemper Virus in Wolves in the Canadian Rocky Mountains

Wild carnivores are often exposed to diseases via contact with peridomestic host species that travel through the wildland-urban interfaces. To determine the antibody prevalences and relationships to human activity for two common canid pathogens, we sampled 99 wolves (Canis lupus) from 2000 to 2008 for antibodies to canine parvovirus (CPV) and canine distemper virus (CDV) in Banff and Jasper National Parks and surrounding areas of the Canadian Rockies. This population was the source for wolves reintroduced into the Northern Rockies of the US. Of 99 wolves sampled, 94 had detectable antibody to CPV (95%), 24 were antibody-positive for CDV (24%), and 24 had antibodies to both pathogens (24%). We tested whether antibody prevalences for CPV and CDV were higher closer to human activity (roads, town sites, First Nation reserves) and as a function of sex and age class. Wolves ≥2 yr old were more likely to be have antibodies to CPV. For CDV, male wolves, wolves ≥2 yr, and those closer to First Nation reserves were more likely to have antibodies. Overall, however, we found minimal support for human influence on antibody prevalence for CDV and CPV. The similarity between our antibody prevalence results and results from recent studies in Yellowstone National Park suggests that at least in the case of CDV, and perhaps CPV, these could be important pathogens with potential effects on wolf populations

The global distribution of Bacillus anthracis and associated anthrax risk to humans, livestock and wildlife.

Bacillus anthracis is a spore-forming, Gram-positive bacterium responsible for anthrax, an acute infection that most significantly affects grazing livestock and wild ungulates, but also poses a threat to human health. The geographic extent of B. anthracis is poorly understood, despite multi-decade research on anthrax epizootic and epidemic dynamics; many countries have limited or inadequate surveillance systems, even within known endemic regions. Here, we compile a global occurrence dataset of human, livestock and wildlife anthrax outbreaks. With these records, we use boosted regression trees to produce a map of the global distribution of B. anthracis as a proxy for anthrax risk. We estimate that 1.83 billion people (95% credible interval (CI): 0.59-4.16 billion) live within regions of anthrax risk, but most of that population faces little occupational exposure. More informatively, a global total of 63.8 million poor livestock keepers (95% CI: 17.5-168.6 million) and 1.1 billion livestock (95% CI: 0.4-2.3 billion) live within vulnerable regions. Human and livestock vulnerability are both concentrated in rural rainfed systems throughout arid and temperate land across Eurasia, Africa and North America. We conclude by mapping where anthrax risk could disrupt sensitive conservation efforts for wild ungulates that coincide with anthrax-prone landscapes

Prevalence of Antibodies to Canine Parvovirus and Distemper Virus in Wolves in the Canadian Rocky Mountains

Wild carnivores are often exposed to diseases via contact with peridomestic host species that travel through the wildland-urban interfaces. To determine the antibody prevalences and relationships to human activity for two common canid pathogens, we sampled 99 wolves (Canis lupus) from 2000 to 2008 for antibodies to canine parvovirus (CPV) and canine distemper virus (CDV) in Banff and Jasper National Parks and surrounding areas of the Canadian Rockies. This population was the source for wolves reintroduced into the Northern Rockies of the US. Of 99 wolves sampled, 94 had detectable antibody to CPV (95%), 24 were antibody-positive for CDV (24%), and 24 had antibodies to both pathogens (24%). We tested whether antibody prevalences for CPV and CDV were higher closer to human activity (roads, town sites, First Nation reserves) and as a function of sex and age class. Wolves ≥2 yr old were more likely to be have antibodies to CPV. For CDV, male wolves, wolves ≥2 yr, and those closer to First Nation reserves were more likely to have antibodies. Overall, however, we found minimal support for human influence on antibody prevalence for CDV and CPV. The similarity between our antibody prevalence results and results from recent studies in Yellowstone National Park suggests that at least in the case of CDV, and perhaps CPV, these could be important pathogens with potential effects on wolf populations

High species diversity of trichostrongyle parasite communities within and between Western Canadian commercial and conservation bison herds revealed by nemabiome metabarcoding

Abstract Background Many trichostrongylid nematode species are reported to infect bison, some of which are major causes of disase and production loss in North American bison herds. However, there is little information on the species distribution and relative abundance of these parasites in either commercial or conservation herds. This is largely because trichostrongylid nematode species cannot be distinguished by visual microscopic examination of eggs present in feces. Consequently, we have applied ITS2 rDNA nemabiome metabarcoding to describe the trichostrongyle parasite species diversity in 58 bison production groups derived from 38 commercial North American plains bison (Bison bison bison) herds from across western Canada, and two bison conservation herds located in Elk Island National Park (EINP) [plains bison and wood bison (Bison bison athabascae)] and one in Grasslands National Park (GNP) (plains bison). Results We report much higher infection intensities and parasite species diversity in commercial bison herds than previously reported in beef cattle herds grazing similar latitudes. Predominant trichostrongyle parasite species in western Canadian commercial bison herds are those commonly associated with Canadian cattle, with Ostertagia ostertagi being the most abundant followed by Cooperia oncophora. Combined with high fecal egg counts in many herds, this is consistent with significant clinical and production-limiting gastrointestinal parasitism in western Canadian bison herds. However, Haemonchus placei was the most abundant species in five of the production groups. This is both surprising and important, as this highly pathogenic blood-feeding parasite has not been reported at such abundance, in any livestock species, at such northerly latitudes. The presence of Trichostrongylus axei as the most abundant parasite in four herds is also unusual, relative to cattle. There were striking differences in parasite communities between the EINP and commercial bison herds. Most notably, Orloffia bisonis was the predominant species in the wood bison herd despite being found at only low levels in all other herds surveyed. Conclusions This study represents the most comprehensive description of parasite communities in North American bison to date and illustrates the power of deep amplicon sequencing as a tool to study species diversity in gastrointestinal nematode communities

Legislative Documents

Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents