Eastern equine encephalitis virus infection

There is no licensed vaccine against EEEV infection for use in humans.

Natural setting

• Avoidance of mosquito bites while in endemic areas is the primary means of prevention. Wearing appropriate clothing (e.g., long-sleeved shirts and long trousers), using insect repellent (e.g., containing DEET [N,N-diethyl-3-methylbenzamide], picaridin, IR3535, or oil of lemon eucalyptus), and using mosquito nets can help reduce the risk of mosquito bites. Staying indoors (ideally with air conditioning) during periods of the day when mosquitoes are most active can also minimise the risk of mosquito bites.[32]Centers for Disease Control and Prevention. Yellow Book. Chapter 3 - Mosquitoes, ticks & other arthopods. Jul 2019 [internet publication]. https://wwwnc.cdc.gov/travel/yellowbook/2018/the-pre-travel-consultation/protection-against-mosquitoes-ticks-other-arthropods CDC: Eastern Equine Encephalitis - Prevention Opens in new window

Laboratory setting

• Animal studies have demonstrated that aerosol transmission of EEEV, in addition to subcutaneous injection, is possible.[30]Reed DS, Lackemeyer MG, Garza NL, et al. Severe encephalitis in cynomolgus macaques exposed to aerosolized Eastern equine encephalitii virus. J Infect Dis. 2007 Aug 1;196(3):441-50. http://jid.oxfordjournals.org/content/196/3/441.long http://www.ncbi.nlm.nih.gov/pubmed/17597459?tool=bestpractice.com [31]Honnold SP, Mossel EC, Bakken RR, et al. Eastern equine encephalitis virus in mice I: clinical course and outcome are dependent on route of exposure. Virol J. 2015 Sep 29;12:152. http://virologyj.biomedcentral.com/articles/10.1186/s12985-015-0386-1 http://www.ncbi.nlm.nih.gov/pubmed/26420265?tool=bestpractice.com Handling high virus concentrations, mouth pipetting, and engaging in activities that generate aerosols (e.g. tissue homogenisation, centrifugation) are risk factors for occupational infection.

• To prevent transmission via the aerosol route, materials infected with EEEV should be handled in a biosafety level 3 laboratory with appropriate use of respirators by laboratory personnel.[1]Public Health Service; Centers for Disease Control and Prevention; National Institutes of Health. Biosafety in microbiological and biomedical laboratories 5th edition. December 2009 [internet publication]. https://www.cdc.gov/labs/BMBL.html [33]Rusnak JM, Kortepeter MG, Hawley RJ, et al. Risk of occupationally acquired illnesses from biological threat agents in unvaccinated laboratory workers. Biosecur Bioterror. 2004;2(4):281-93. http://www.ncbi.nlm.nih.gov/pubmed/15650438?tool=bestpractice.com

EEEV infection is a notifiable disease in some countries, including the US. It is not transmitted through direct contact with infected equines or humans. No post-exposure prophylaxis is available.

If meningitis or meningoencephalitis is suspected, droplet precautions may be necessary in hospitalised patients until bacterial infections are excluded.