On the natural occurrence of California encephalitis virus and other arboviruses in Alaska

California encephalitis virus (Snowshoe Hare strain) was isolated from these Alaskan sources: varying hare (snowshoe hare), Lepus americanus Erxleben; indicator rabbit, Oryctolagus cuniculus (Linnaeus); varying lemming, Dicrostonyx rubricatus (Richardson); northern red-backed vole, Clethrionomys rutilus (Pallas); mosquitoes, Aëdes spp.; and blackflies, Simulium sp. This virus has been confirmed as enzootic in east-central Alaska. Other arbovirus isolations were Silverwater virus, from hare-ticks, Haemaphysalis leporispalustris (Packard); Great Island virus and a virus of the Sakhalin group from bird ticks, Ixodes signatus Birula, from common murres, Uria aalge (Pontoppidan); and Northway virus, a hitherto undescribed member of the Bunyamwera group from a northern red-backed vole, from indicator rabbits, and from hematophagous Diptera. These findings include new host-records and extensions of the known geographic range of some of the viruses isolated.