Silverwater virus is enzootic in a population of snowshoe hares in north-central Alberta. Over a 9-year period, prevalence of neutralizing antibody in adult hares has been 31%, compared with 17% for juveniles. Antibody prevalence in adult hares ranged from 3% in 1961 to 47% in 1963. The relation of Silverwater virus to the snowshoe hare's 10-year cycle of abundance was examined. Neutralizing antibodies were also detected in five other mammalian species in Alberta and in lagomorphs from Wisconsin and Utah. The agar-gel double diffusion technique was unsuitable for detecting Silverwater virus antibodies in hare sera.
Present address: University of Wisconsin, Madison, Wisconsin.
Present address: Sonoma State College, Cotati, California 94928.