California Encephalitis Virus

Abstract

This chapter provides an overview of the classification and description of California encephalitis (CE) virus, its hosts, the key developments regarding the virus, and the diagnostic techniques and reagents. It is a member of the California group of viruses. It causes a mild to severe febrile disease, occurring in young children. The hosts that are infected by California encephalitis virus include man and small mammals, primarily California ground squirrels. California encephalitis virus, the prototype of the California complex, was originally isolated in 1943 from Aedes melanimon mosquitoes collected in Kern County, California. Small mammals serve as the amplifying hosts in the summer cycle with transovarial transmission, which is the only potential overwintering mechanism to date. The preferred viral diagnosis is the inoculation of tissue culture with confirmation by fluorescent antibody technique. In some instances, a more expensive but sensitive method of intracerebral suckling mouse inoculation may be required to obtain an isolate. Specific neutralization tests may be required for the virus identification of isolates that come from areas where other closely related California group viruses occur. The preferred serological diagnosis is plaque reduction neutralization. This technique is the most sensitive, has the greatest dependability but is the most expensive.