This virus is another member of the Alphavirus genus of Togavirus. It is also a mosquito-borne virus that is seen in the Southern United States, Central America, and South America.
Transmission: Mosquito-borne
Incubation period: 2-6 days
Disease presentation: There is a sudden onset of flu-like symptoms including headache, chills, fever, congestion, retro-orbital pain, nausea, and vomiting. Lymphoadenopathy occurs in one third of the cases. Most cases are mild and symptoms only last 3-5 days. In some cases however, the virus can be biphasic and return with more serious presentations 6-9 days after onset. In the most sever cases, the virus invades the CNS, causing encephalitis, convulsions, paralysis, coma, and/or death. Less than 10% of adults infected with the virus usually die and 20-30% of children infected with the virus die.
Prevention: There is currently a vaccine (DOD TC-83) in IND status which incurs limited protection and 20% of people do not respond to the vaccine. There is also another IND vaccine (DOD TC-84) that is used for the 20% of people who do not respond to the first vaccine. These vaccines do not protect against all serotypes however.
Treatment: No specific treatment, just supportive care.