Failure to identify alveolar echinococcosis in trappers from South Dakota in spite of high prevalence of Echinococcus multilocularis in wild canids

Echinococcus multilocularis causes a rare but potentially lethal zoonotic d isease in humans. This tapeworm has been known to be endemic in foxes (Vulp es vulpes) and coyotes (Canis latrans) within the northern United States si nce the 1960s. One purpose of this study was to provide recent data on the prevalence of E. multilocularis in foxes and coyotes from eastern South Dak ota. In a survey conducted from 1987 to 1991 and involving 137 foxes and 9 coyotes from this area, 74.5% of the foxes and 4 of the coyotes were infect ed. To assess the possible prevalence of alveolar echinococcosis in a group at presumptive high risk, we also conducted a serological survey of member s of the South Dakota Trappers Association in 1990 and 1991. Serum samples from 115 trappers were evaluated for the presence of E. multilocularis anti bodies using enzyme-linked immunosorbent assay tests involving a purified a ntigen called Em2, a crude E, multilocularis antigen, and a recombinant E. multilocularis antigen called II/3-10. None of the trappers showed antibody evidence for the presence of E. multilocularis. Roughly half of the survey ed individuals had trapped more than 50 foxes during their life, and almost one-fourth had trapped more than 1,000 foxes.