D. I. Ivanovsky Institute of Virology and N. F. Gamaleya Institute of Epidemiology and Microbiology, USSR Academy of Medical Sciences, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control, Moscow, USSR
Four California serogroup viruses isolated from mosquitoes in the USSR were tested for antigenic analogy with prototype viruses of the California serogroup. The topotype isolates are biologically similar to, but antigenically different from each other. One is a subtype of snowshoe hare virus, two are different subtypes of Tahyna, Lumbo, and snowshoe hare viruses, and one is identical to Inkoo virus, previously isolated only in Finland. The results indicate that molecular studies of these viruses are necessary to comprehend their evolution.