Prevention centers on controlling mosquitoes and avoiding mosquito bites. Eastern equine encephalitis is a rare disease that is spread to horses and humans by infected mosquitoes. It is among the most serious of a group of mosquito-borne virus diseases that can affect the central nervous system and cause severe complications and even death. Other similar diseases are western equine encephalitis, St. Louis encephalitis, and LaCrosse encephalitis. Eastern equine encephalitis is caused by the eastern equine encephalitis virus, an arbovirus.
Arbovirus is short for ar thropod- bo rne virus .
In the United States, arboviruses are spread mainly by infected mosquitoes. Birds are the source of infection for mosquitoes, which can sometimes transmit the infection to horses, other animals, and, in rare cases, people. Eastern equine encephalitis is found in North America, Central and South America, and the Caribbean. In the United States, most cases have been reported from the eastern seaboard states, the Gulf Coast, and some inland midwestern areas. The eastern equine encephalitis virus has a complex life cycle involving birds and a specific type of mosquito, Culiseta melanura , that lives in marshes and swamps.