Western equine encephalitis virus in Saskatchewan garter snakes and leopard frogs.

Western equine encephalitis virus was isolated from two naturally infected snakes on first bleeding and from seven others at subsequent bleedings, both with and without preliminary chilling. One snake, with neither detectable virus nor serum neutralizing antibodies when first bled, developed viremia later. Viremia in garter snakes has a cyclic rhythm independent of the temperature of the environment. Virus was isolated from 6 frogs, and 50 out of 179 had detectable serum neutralizing antibodies. Infections with this virus are widely distributed in garter snakes and leopard frogs in the agricultural area of Saskatchewan.