California encephalitis virus proliferation in Yukon mosquitoes incubated at low temperatures.

Replication of a subarctic Bunyavirus, California encephalitis (snowshoe hare subtype), was detected in salivary glands and thoraces of wild-caught Aedes communis mosquitoes from the Yokon Territory, after intrathoracic inoculation with 0.1 to 100 mouse LD50 virus, and incubation for 7 to 21 days throughout their viable temperature range of 0 to 23 degrees C. Immunoperoxidase staining confirmed that viral replication occurred in the cytoplasm of acinar cells of salivary glands, both by ligh microscopy and electron microscopy. Replication of another subarctic Bunyavirus, Northway, and a subtropical Flavivirus, Murray Valley encephalitis, was also demonstrated by infectivity by infectivity titrations and immun operoxidase reactions in salivary glands of A. communis incubated at 0, 13, and 23 degrees C for 7 to 21 days.