Graphic by Anjali Rao-Herel ’22
BY FIONA HINDS ’21
Eastern Equine Encephalitis (EEE) is an extremely rare, mosquito-transmitted disease first identified in Massachusetts in 1938. According to 7News Boston, there had been seven reported cases of EEE in Massachusetts as of Sept. 6.
According to Mass.gov, less than 100 cases have ever been reported in the state. While mammals such as humans, horses and goats can contract the disease, they cannot spread it. Only about 5 percent of people exposed to the virus contract the disease.
A positive test of EEE in a person or animal automatically raises the threat level in a community and its surroundings to “critical.” Eight horses and one goat have tested positive for EEE in Massachusetts this year. In total, there are currently 32 communities at “critical risk,” 42 at “high risk” and 115 at “moderate risk” for EEE in Massachusetts, according to the Department of Public Health. The community of South Hadley is currently at “high risk.”
In Sudbury, where one case of EEE has been confirmed, health and town officials are working on protecting and informing residents about the disease. Aerial spraying, which focuses on school grounds, parks and fields, is expected to continue throughout the coming week.
According to the Center for Disease Control and Protection (CDC), the virus that causes EEE is maintained in a cycle between mosquitoes and birds. Mosquitoes become carriers of the disease when they bite an infected bird. Although mosquito populations are beginning to decrease with cooler weather, EEE risk in the state persists.
Dr. Catherine Brown, an epidemiologist in the state of Massachusetts, told the Boston Globe that risk continues not until the first frost, but the first “hard frost.” A hard frost occurs when temperatures are low long enough for the ground to freeze, which is usually around 27 degrees. Historically, most people who contract the disease in Massachusetts become sick before Sept. 15, when temperatures begin falling.
As EEE is spread by mosquitoes, steps may be taken to reduce the risk of being bitten. Mass.gov suggests wearing long sleeves and long pants to cover skin, using bug spray or other bug repellant and avoiding being outside between the hours of dawn and dusk.
More information can be found by contacting the Massachusetts Department of Public Health, Division of Epidemiology and Immunization, mosquito control in your area or local board of health.