Virginia Mosquitoes

Eastern Eq​uine Encephalitis

Historical Data

• Between 1975 and 2009, there have been five cases in Virginia, the most recent was in 2003. Most cases are of infected horses that are too young to have gotten the vaccine. People do not get it that often because the mosquito would have to carry the virus, and it is not that common for the vector to carry. About eight cases are reported each year in the U.S. mostly near Atlantic, Gulf, and Great Lakes regions.

• It is a not common illness in humans. Most cases occur on the Atlantic and Gulf coasts. Causes disease in horses, humans, and some birds.

Symptoms

• Most people do not have symptoms, but severe cases include symptoms of headache, vomiting, high fever, and chills.

• Encephalitis is the inflammation of the brain. It could even get to disorientation, seizures, and coma.

• If the patient survives, they live with brain damage. There is a 33% mortality rate.

Transmission

• The virus undergoes a cycle with Culiseta melanura mosquitoes, this mosquito is not really considered a vector for humans because it feeds on birds mostly. The vectors of this disease are only mosquitoes that feed on humans and birds like  Aedes, Coquillettidia, and Culex species. Both humans and horses are considered dead- end hosts for the virus. The virus infected mosquitoes are usually in very swampy areas where not many humans live, so only visitors get the disease most of the time.

• Infected by a bite of a mosquito that carries it. There are 27 types that carry the virus.

Pathogens

• it is an alphavirus belonging to genus Alphavirus and family Togaviridae. EEEV is a single stranded RNA genome. There are four different lineages of the virus. Group 1 mostly affects humans in North America and the Caribbean, while the other three mostly affect horses in Central and South America.

Treatment

• There is no real treatment for the disease, just for the symptoms.