Abstract

A hair-loss syndrome has affected both Columbian black-tailed (Odocoileus hemionus columbianus) and white-tailed deer (Odocoileus virginianus leucurus) in western Oregon since 1998. Its distribution is widespread, seasonal, and limited to native species of deer. The population effects of this syndrome have not been fully measured, but it remains a cause of significant mortality and morbidity on an annual basis. A consistent finding in necropsies done on affected deer is the presence of large numbers of chewing lice, identified as an indeterminate species of Damalinia (Cervicola), a genus of chewing lice historically associated with Asiatic deer and African antelope. Genetics studies have supported this morphologic distinction between exotic and native families of sampled deer chewing lice. Sampling results of lice on native and captive exotic deer demonstrate a spatial relationship between native and exotic chewing lice of deer within the state. Of the 93 mule deer (Odocoileus hemionus) sampled outside of the hair-loss syndrome endemic area, all lice examined were Damalinia (Tricholipeurus) sp., native lice of North American deer. Observational data of the hair-loss syndrome demonstrate a temporal pattern that supports a spatial movement of the syndrome.