Cache Valley virus: isolations from mosquitoes in Saskatchewan, 1972-1974.

Eighteen isolations of Cache Valley virus (Bunyaviridae) were obtained from a total of 113,694 mosquitoes collected in Saskatchewan during the summers of 1972 to 1974. Most of the isolations were from mosquitoes collected during August. Culiseta inornata, the most abundant mosquito (38% of total collected), had the highest minimum vector-infection rate (0.

Intranasal exposure of the Richardson's ground squirrel to Western equine encephalomyelitis virus.

Adult Richardson's ground squirrels were infected with western equine encephalomyelitis virus by intranasal instillation. Mortality followed the instillation of a minimum threshold of 4.7 logs of virus while infection was produced by a dosage of 2.

Subcutaneous exposure of the Richardson's ground squirrel (Spermophilus richardsonii Sabine) to western equine encephalomyelitis virus.

Both adult and suckling Richardson's ground squirrels (Spermophilus richardsonii) were susceptible to subcutaneous exposure with western equine encephalomyelitis (WEE) virus, but the virus was more virulent for sucklings than adults. In sucklings, the incubation period was from 4 to 5 days, followed by apparent signs of central nervous system (CNS) involvement. Death occurred 10 to 13 days postexposure.