Last Update: March 2000
Author: F. A. Leighton
Reviewer: H. Artsob
JC virus is classified in the Genus Bunyavirus of the family Bunyaviridae. It is an enveloped, single-stranded RNA virus. JC virus is one of a large group of related arboviruses called "California Serogroup" viruses. This group includes Snowshoe Hare Virus, the other serogroup member associated with human disease in Canada. The California Serogroup derives its name from the first virus of the group that was recognized - California Encephalitis Virus - which was isolated from mosquitoes in California in 1943. JC virus was first isolated in 1962 from a mosquito in Colorado and was first recognized as able to cause disease in humans in 1980. The first recognized case in Canada occurred in 1981 in Ontario.
JC virus has been found in Newfoundland, Quebec, Ontario, Manitoba and Saskatchewan, and the Northwest Territories. It has been recorded in some north central states and in Alaska. It probably occurs throughout temperate climate zones of North America.
JC virus persists in cycles of infection among wild ungulates, especially the White-tailed Deer (Odocoileus virginianus), and several different species of mosquito of at least two genera: Aedes and Anopheles. Since the range of the virus extends beyond the range of the White-tailed Deer, other mammalian hosts must also participate in the maintenance of JC virus. There is evidence that Moose (Alces alces), Elk (Cervus elaphus), Mule Deer (Odocoileus hemionus) and Pronghorn (Antilocapra americana) can serve as mammalian hosts for the virus and as sources of infection for host mosquitoes. Thus, JC virus is maintained in a variety of different ecological associations of ungulates and mosquitoes in a wide range of different habitats and geographical regions.
No disease caused by JC virus has been recognized or suspected in wild or domestic animals.
Human disease caused by JC virus has occurred in Ontario and in the Northwest Territories. Relatively little is known about this virus as a cause of human disease. In a series of 12 cases reported in 1981 in the United States, 11 recovered and one died. Illness in people infected with JC virus is due to infection and inflammation of the brain (encephalitis and meningitis).
JC virus sometimes is detected in surveys and surveillance programs for arboviruses in general, but has not been the object of specific surveillance and public health programs. Only a small number of cases of human illness due to this virus have been recognized.
Artsob, H. 1983. Distribution of California serogroup viruses and virus infections in Canada. In: Calisher C.H. and W.H. Thompson (eds.) California Serogroup Viruses. New York: Alan R. Liss, Inc., p. 277-290.
Artsob, H. 1990. Arbovirus activity in Canada. Archives of Virology. Supplement 1: 249-258.
Grimstad P.R. 1988. California group viruses. In: Monath T.P. (ed.) The Arboviruses: Epidemiology and Ecology. Boca Raton: CRC Press, Inc., p. 99-136.
Grimstad, P.R. 1994. California group viral infections. In: Beran, G.W.(Editor-in-chief) Handbook of Zoonoses. 2nd Edition. Section B Viral. CRC Press Inc. Boca Raton. p. 71- 79.