Western Equine Encephalitis in Saskatchewan Reptiles and Amphibians, 1961-1963.

Western equine encephalitis (WEE) antibodies were found in blood samples from garter snakes and leopard frogs collected in Saskatchewan but WEE virus was not recovered from any of the specimens. Evidence of natural WEE infection in snakes was found in 8 different localities while in frogs in two only. Experimentally, garter snakes were readily infected and developed a high, relatively sustained viremia without signs of disease. After experimental exposure, viremia persisted regularly for 10 to 12 days, while the longest observed duration of viremia was 30 days. Anamnestic responses were elicited in snakes as a result of second inoculations of virus after the antibody levels from first exposures had fallen. Newborn snakes were observed to be more sensitive to infection than adults. The possibility of virus and antibody transmission from infected pregnant garter snakes to their offspring was investigated. Snakes and frogs were both susceptible to infection by the oral route. Two bull snakes collected at Steveville, Alberta, were found to have antibody for St. Louis Encephalitis virus.