Eastern equine encephalitis virus (EEEV) is a mosquito-borne virus that can cause symptoms that resemble influenza or dengue fever (e.g., fever, malaise, headache, nausea) with or without neurological (encephalitic) symptoms (e.g., altered mental status, seizures). Neurological involvement is not uncommon with EEEV infection, and it typically results in long-term neurological sequelae or death.
EEEV is the most deadly encephalitic arbovirus in North America, with a case fatality rate of 30% to 50%.
EEEV infection occurs mainly in North America, around the eastern seaboard and Gulf coast states. In North America, the Culiseta melanura mosquito maintains the natural enzootic transmission cycle with passerine birds. In South America, rodents are thought to be the natural reservoir for EEEV, and the Culex (Melanoconion) mosquito species the main vector.
Diagnosis is based on clinical presentation and geographical clues. Confirmation of diagnosis is via serological detection of antibodies against EEEV (e.g., using ELISA with plaque reduction neutralisation tests).
There is no specific treatment for EEEV infection. Supportive care with management of specific symptoms is advocated.
Avoidance of mosquito bites is the best method of prevention. There is no licensed vaccine for use in humans.
Eastern equine encephalitis virus (EEEV) is a positive-sense single-stranded RNA virus (family: Togaviridae; genus: Alphavirus ) transmitted by mosquitoes.
In humans infected with EEEV, the incubation period ranges from 4 to 10 days, and duration of acute illness is typically days to weeks depending on severity.  Humans infected with EEEV may be asymptomatic, or they may develop symptoms that resemble influenza or dengue fever (e.g., fever, malaise, headache, nausea) with or without neuroinvasive symptoms (e.g., altered mental status, seizures). The mortality rate for humans with neuroinvasive disease is approximately 30% to 50%.  EEEV is the most deadly encephalitic arbovirus in North America.
Division of Infectious Disease and Global Medicine
University of Florida
AV is the author of a reference cited in this monograph.
Infectious Diseases Consultant
Naples Community Hospital
MGM declares that he has no competing interests.
US Naval Medical Research Unit 6 (NAMRU-6)
SV declares that he has no competing interests.
Use of this content is subject to our disclaimer