Epizootiologic Survey of Mycobacterium Bovis in Wildlife and Farm Environments in Northern Michigan

Abstract

ABSTRACT:Bovine tuberculosis (bovine TB), caused by Mycobacterium bovis, has reemerged in northern Michigan, USA, with detections in white-tailed deer (Odocoileus virginianus) in 1994 and in cattle in 1998. Since then, significant efforts have been directed toward reducing deer densities in the area in the hopes of reducing the bovine TB prevalence rate in deer and eliminating spillover of the disease into cattle. Despite the success of the efforts to reduce deer densities, additional cattle herds have become infected. Other mammals can be infected with M. bovis, and some carnivores and omnivores had been found to be infected with the disease in northern Michigan, USA. We conducted a multiyear surveillance effort to detect bovine TB in wild species of mammals in the Michigan, USA, outbreak area. . We also found two raccoons and four opossums to be positive for Mycobacterium avium. We collected 503 environmental samples from cattle farms recently identified as bovine TB positive; none yielded positive M. bovis culture results. Finally, we used infrared cameras to document wildlife use of four barns in the area. Many avian and mammalian species of wildlife were observed, with raccoons being the most commonly observed species. This surveillance study identified no new wildlife species that should be considered significant reservoirs of bovine TB in the outbreak area in northern Michigan, USA. However, the relatively high, apparent bovine TB prevalence rates in some carnivorous and omnivorous species, their relatively long life spans, and their frequent use of barns, suggests that removal of raccoons, opossums, foxes, and coyotes (Canis latrans) should be considered when a newly infected farm is depopulated of cattle.

Linking Bovine Tuberculosis on Cattle Farms to White-Tailed Deer and Environmental Variables Using Bayesian Hierarchical Analysis

“…Environmental variables have been documented to contribute to presence or viability of infectious agents of disease in several areas in North American and Europe [17], [44], [45] although environmental sampling has yet to identify M. bovis on cattle farms in this region [46], [47]. Variables to consider should be based on a priori knowledge of the disease agent studied and mechanisms that may hinder or promote survival.…”

A Study of the Persistence ofMycobacterium bovisin the Environment under Natural Weather Conditions in Michigan, USA

“…The role of M. bovis contaminated environmental substrates in the interspecies transmission of bovine TB between cattle and deer has also been investigated [8, 9]. Although M. bovis was not identified from any of the environmental substrates tested, particular cattle management practices and environmental factors were identified that have been shown to be associated with tuberculosis on cattle farms in northeast Michigan in the past [10].…”

The Pathology of Mycobacterium tuberculosis Infection

“…The MDR strains account for almost 5% of TB cases. 70 Because veterinary species are infected by Mtb, and because we can apply what is known about Mtb to the fight against M. bovis, which has reemerged in the United States and other countries due to persistence within wildlife reservoirs 218 and for which MDR strains have been reported, 105 it is critical that veterinary pathologists have a good basic understanding of Mtb. This review therefore strives to summarize the key components of the microbiology, cell biology, immunology, and pathology of Mtb that are pertinent for the veterinary pathologist.…”