Alphaviruses

Abstract

There are 31 registered alphaviruses belonging to the family Togaviridae, 16 of which are known to cause human infection. They are RNA viruses with global geographical distribution and complex transmission cycles, usually between wild or domestic animals and one or more mosquito species; humans are infected by mosquito bites and are often incidental hosts that do not contribute to the maintenance of the virus. They cause a spectrum of clinical manifestations ranging from non-specific febrile illness to chronic arthralgia to acute encephalitis and death. Diagnosis of infection is made by several methods including serologically by detection of IgM and/or IgG antibodies, virus isolation, molecularly using reverse transcription–polymerase chain reaction, or by immunohistochemistry on tissue samples.