INFESTATION OF LICE AMONG WILD CANIDS IN ALASKA

Several biological and social concerns regarding louse infestations in wild Alaskan canids were identified following the recently discovered infestation of lice on wolves (Canis lupus) and coyotes (C. latrans) in the Mat–Su Valley. The biting dog louse (Trichodectes canis) was first identified on a coyote and then on several wolves harvested on the Kenai Peninsula during the winters of 1981–82 and 1982–83. The department attempted to eliminate the louse infestation among the wild canids by capturing and treating them with injections of the antiparasitic drug ivermectin and with ivermectin-treated baits. This effort was not successful in stopping the spread of the infestation, because of the difficulty in catching and treating all infested animals, and funding was stopped precluding treatment after the second winter. In November and December 1998 trappers reported catching wolves and coyotes with evidence of lice in the Mat– Su Valley. Similar efforts to those on the Kenai resulted in all known infested wolves being treated. The results of trying to eliminate lice in coyotes with treated baits were not known. The operational cost of the effort in the Mat–Su Valley was $60,000. The rapid spread of lice among wolves on the Kenai and the recent outbreak in the Mat–Su Valley raises serious concerns that a similar infestation can happen elsewhere in the state. The source of lice in both areas was believed to be domestic dogs, which are infested with lice in a low-level enzootic stage throughout Alaska. The spread of lice to Interior coyotes and wolves, in particular, could have significant effects on the trapping economy and on the quality of wolf viewing. The relationships between parasites and their hosts can be complex, involving lengthy adaptations to each other. With the spread of lice, we may see higher morbidity of wolves and coyotes, particularly among young animals. However, there is no evidence of direct mortality from lice or of a negative population effect from lice on wolves or coyotes in Alaska or the lower 48 states.