California encephalitis virus transmission by arctic and domestic mosquitoes

Abstract

A zero passage arctic mosquito isolate of California encephalitis (CE) virus (showshoe hare subtype) was transmitted by wild-caughtAedes communis mosquitoes after 13 days incubation at 13° and 23° C, after 20 days incubation at 13° C, when mosquitoes imbibed 1 mouse LD₅₀ in a blood meal. Transmission occurred after 20 days incubation at 13° and 23° C when mosquitoes were injected intrathoracically with 1 or 0.1 mouse LD₅₀. Virus was also transmitted byA. aegypti 13 days after infection with 100 mouse LD₅₀ by feeding or intrathoracic injection, and incubation at 13° C. Virus antigen was detected in salivary glands of 42 per cent virus-positiveA. communis mosquitoes by direct immunofluorescence, and in 50 per cent or less ofA. aegypti mosquitoes by immunoperoxidase and immunofluorescence, with somewhat greater regularity by the indirect than the direct technique.