OCCUPATIONAL EXPOSURE TO MYCOBACTERIUM-BOVIS INFECTION IN DEER AND ELK IN ONTARIO

In late 1991, two herds of deer and elk were depopulated at a slaughte ring plant in Ontario, followed by processing of infected animals at a rendering plant. We conducted a questionnaire plus tuberculin skin-te st survey of 104 exposed slaughtering and rendering plant workers, and government veterinarians and inspectors. Overall, 17 participants wer e skin-test positive; one of 51 initially skin-test negative subjects tested a second time three months later became positive, consistent wi th the risk associated with occupational exposure during the depopulat ion of tuberculous elk previously observed in Alberta. Deer farming is widespread, with 263 herds in Ontario. The likely route of transmissi on is through aerosols. Possible reasons for the low conversion rate i nclude the use of respiratory protection, absence of a tanning plant, an enclosed rendering plant process, and late skin testing which may h ave underestimated the number of conversions. Recommendations for prev ention are summarized; in particular, respiratory protection for work with infected herds should probably include high efficiency particulat e face masks.