MOLECULAR EPIDEMIOLOGIC STUDIES OF MYCOBACTERIUM-BOVIS INFECTIONS IN HUMANS AND ANIMALS IN SWEDEN

Forty-nine isolates of Mycobacterium bovis from humans and animals in Sweden were analyzed by restriction fragment length polymorphism (RFLP ) patterns probed by the insertion element IS6110. Most isolates had p atterns indicating the presence of only one or two genomic copies of t he IS6110 insertion element. This simple type of pattern was found in all human isolates. In contrast, isolates from M. bovis infections in five herds of farmed deer in Sweden showed a specific RFLP pattern wit h seven bands, indicating seven copies of the IS6110 sequence. In 1958 , Sweden was declared free from M, bovis in cattle, However, in 1987, M. bovis was reintroduced with imported farmed deer, and since 1991, 1 1 outbreaks in deer herds, but not in other livestock or wildlife, hav e been diagnosed. Continued RFLP studies of the new Swedish M. bovis i solates can reveal possible transmission of this deer strain to other animals or humans.