view 2009 WNV and EEE activity in Massachusetts (MDPH)

view Historical WNV and EEE data in Massachusetts: 2008 (MDPH)

view 2009 WNV Activity in the United States

Trends

West Nile Virus

West Nile virus was first detected in birds and mosquitoes in Massachusetts in 2000. Since then, the severity of risk posed by the virus initially increased (2001-2002) and then declined throughout the Northeast through 2008.

Between 2001 and 2008, 79 Massachusetts residents were infected with West Nile virus, including six people who died. There were no human fatalities from the virus between 2006 and 2008.

Eastern Equine Encephalitis

Massachusetts has the second largest number of reported human cases of eastern equine encephalitis in the country. Between 1964 and 2008, 257 people in the U.S. were infected with the EEE virus. Of these people, 14% resided in Massachusetts.

Outbreaks of eastern equine encephalitis occur in Massachusetts about every 10 to 20 years. An outbreak typically lasts two to three years. The most recent outbreak of EEE in Massachusetts occurred from 2004 to 2006, and included 13 cases with six fatalities. During this period, infected mosquitoes were detected in Plymouth, Bristol, Middlesex, Worcester, Norfolk, and Essex counties. There were no human cases of EEE reported in 2007 and one human case in 2008.

Revised on August 14, 2009