Investigation of the transmission of Mycobacterium bovis from deer to cattle through indirect contact

Abstract

Objective—To investigate the infection of calves with Mycobacterium bovis through oral exposure and transmission of M bovis from experimentally infected white-tailed deer to uninfected cattle through indirect contact. Animals—24 11-month-old, white-tailed deer and 28 6-month-old, crossbred calves. Procedure—In the oral exposure experiment, doses of 4.3 × 106 CFUs (high dose) or 5 × 103 CFUs (low dose) of M bovis were each administered orally to 4 calves; as positive controls, 2 calves received M bovis (1.7 × 105 CFUs) via tonsillar instillation. Calves were euthanatized and examined 133 days after exposure. Deer-to-cattle transmission was assessed in 2 phases (involving 9 uninfected calves and 12 deer each); deer were inoculated with 4 × 105 CFUs (phase I) or 7 × 105 CFUs (phase II) of M Bovis. Calves and deer exchanged pens (phase I; 90 days' duration) or calves received uneaten feed from deer pens (phase II; 140 days' duration) daily. At completion, animals were euthanatized and tissues were collected for bacteriologic culture and histologic examination. Results—In the low- and high-dose groups, 3 of 4 calves and 1 of 4 calves developed tuberculosis, respectively. In phases I and II, 9 of 9 calves and 4 of 9 calves developed tuberculosis, respectively. Conclusions and Clinical Relevance—Results indicated that experimentally infected deer can transmit M bovis to cattle through sharing of feed. In areas where tuberculosis is endemic in free-ranging white-tailed deer, management practices to prevent access of wildlife to feed intended for livestock should be implemented. (Am J Vet Res 2004;65:1483–1489)

Evaluation of the Epidemiological Relevance of Variable-Number Tandem-Repeat Genotyping ofMycobacterium bovisand Comparison of the Method with IS6110Restriction Fragment Length Polymorphism Analysis and Spoligotyping

“…Likewise, direct transmission between wildlife and farmed animals has not been demonstrated yet under natural conditions. Nev-ertheless, it has been demonstrated that experimentally infected deer can transmit M. bovis to cattle through the sharing of feed (22).…”

Characteristics of white-tailed deer visits to cattle farms: implications for disease transmission at the wildlife–livestock interface

“…Bucks are more likely to be bTB-positive than does and should be included in any mitigation methods considered. For pathogens that can be transmitted between livestock and wildlife, the risk for transmission often increases near farms (Palmer et al 2004). Focusing on culling, vaccine deployment or other mitigation methods on farms may serve as a logistically and financially effective method to target deer that are at highest risk for transmission of pathogens between livestock.…”

“…Studies by Palmer et al (2004), suggest indirect contact resulting from shared feed is a likely mechanism for intraspecific transmission between deer and interspecific transmission between deer and cattle. Epidemiologic investigations of infected white-tailed deer in Michigan found supplemental feeding of deer likely contributes to infection in deer with subsequent spillover to cattle (Miller et al 2003).…”

“…Overlapping space use can lead to interspecific interactions resulting in disease spread (Riley et al 1998). In addition, sharing environmental resources has been identified as a mechanism for disease transmission between wildlife to livestock (Roper et al 2003;Palmer et al 2004;Böhm et al 2009). Thus, to gain insight into the dynamics of disease transmission it is necessary to examine how animals use forage resources and where and when potential interspecific contact may result.…”

T-Cell mRNA Expression in Response toMycobacterium bovisBCG Vaccination andMycobacterium bovisInfection of White-Tailed Deer

“…Epidemiological and strain typing evidence suggests that infected WTD serve as a reservoir since interspecies transmission from deer to cattle occurs (21,25,29). In Minnesota, infected WTD have been found adjacent to infected cattle (http://www.bah.state.mn.us/tb/).…”