The Proceedings of the 1982 International Symposium on California (CAL) Serogroup Viruses provided a detailed review of La Crosse (LAC) virus in particular. Many North American studies of the CAL group prior to the early 1970s are somewhat confusing in that the etiological agents discussed were not clearly identified. Official records list all clinical cases as California encephalitis. This terminology may be acceptable in clinical circles since treatment for severe viral infections would be similar for CAL group neuropathogens; from an epidemiological standpoint, however, this is insufficient. With CAL group viruses, human disease occurs endemically, often in rural or suburban populations, and is generally mild or inapparent. Thus, the social impact of the CAL group has been limited for the most part with little recognized impact on human populations in general. The California serogroup is but one of 16 serogroups within the genus Bunyavirus of the family Bunyaviridae.