Eastern equine encephalitis virus

Microbiology

• Virus in the Togaviridae family and Alphavirus genus

Epidemiology

• Mosquito-borne avian infection carried by the Culiseta melanura mosquito
• Horses and humans are dead-end hosts, infected by bridge vectors including Aedes vexans and Coquillettidia perturbans
• Only one human case ever recorded in Ontario

Clinical Manifestations

• Most are asymptomatic
• Incubation period of 4 to 10 days
• For those who develop disease, it usually begins with an influenza-like illness, with fever, malaise, arthralgia, and myalgia, which lasts one to two weeks
• Some people develop neurologic disease during the febrile illness, which may progress to encephalitis
• There is a high mortality rate among those who develop encephalitis, with death usually occuring between 2 and 10 days after illness onset
• It is possible to have permanent and severe neurologic sequelae