Alphavirus

One of the genera of the family Togaviridae that was formerly classified as part of the “group A” arboviruses and includes the viruses that cause eastern equine, western equine, and Venezuelan encephalitis.

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Al·pha·vi·rus 'al-fə-.vī-rəs n a genus of single-stranded RNA viruses of the family Togaviridae that are transmitted by arthropods and esp. mosquitoes and that include the Mayaro virus, Semliki Forest virus, Sindbis virus, and the causative agents of chikungunya and equine encephalomyelitis

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n.

any member of a genus of arbovirus transmitted by mosquitoes. Many alphaviruses can cause disease in humans and animals, including O'nyong nyong fever and Ross River fever.

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Al·pha·vi·rus (alґfə-vi″rəs) [alpha the first letter of the Greek alphabet + virus] a genus of viruses of the family Togaviridae that cause encephalitis or febrile illness with rash or arthralgia, including eastern, western, and Venezuelan equine encephalitis viruses, chikungunya virus, Everglades virus, igbo-ora virus, Mayaro virus, o'nyong-nyong virus, Ross River virus, Semliki Forest virus, and Sindbis virus. Formerly called group A arboviruses. alphaviral adj