Mildly affected horses my recover over a few weeks but may be left with permanent brain damage. Differential diagnoses for EEE include hepatoencephalopathy, rabies, protozoal myeloencephalitis, verminous encephalitis, botulism, and leukoencephalomalacia. There is no treatment for EEE other than good nursing care and supportive therapy. Human Eastern Equine Encephalitis is a rare but severe neurologic disease. About five human cases are confirmed annually in the United States.
People also acquire the infection from mosquitoes.
EEE in people is characterized by an acute onset of fever and flu-like symptoms such as headache, sore throat and lethargy. This progresses rapidly to delirium, coma and possible death. The fatality rate in people is 30 percent. There is no vaccine or specific therapy other than supportive care. Permanent brain damage and long-term sequellae are likely.