Eastern equine encephalitis: an emerging arboviral disease threat, Maine, 2009

Eastern equine encephalitis (EEE) is one of the most severe arboviral encephalitides in North America. Before 2009, limited nonhuman EEE virus activity had been reported in Maine, all from the southernmost area of the state. No human case has been reported in a Maine resident.

We review all EEE virus activity reported to Maine Centers for Disease Control in 2009 and describe current testing practices for possible human EEE cases.

In 2009, fatal cases of EEE were identified in 15 horses, 1 llama, and 3 flocks of pheasants in Maine, with activity extending into the central part of the state. Although no human EEE cases were identified, diagnostic testing practices of most meningitis and encephalitis cases were inadequate to exclude EEE.

Work to better define the expanding range of EEE virus in Maine is warranted, along with education of healthcare providers regarding appropriate testing for this serious disease.