This past year has seen the worst outbreak of mosquito-borne eastern equine encephalitis in Massachusetts since the 1950s. State public health officials reported 12 EEE cases, and four deaths resulting from the disease in Massachusetts during 2019, and unfortunately, 2020 will likely see another EEE outbreak in the state. Experts state that EEE outbreaks occur every 10 to 20 years, with each one lasting for three consecutive years. For example, the last EEE outbreak in Massachusetts began in 2010 and ended in the late fall of 2012. This three year period saw nine reported EEE cases including four fatalities in the state, fewer than the number of cases reported this year alone. In order to minimize the disease’s potential impact in 2020 and 2021, public health officials in Massachusetts and elsewhere are working to better understand what made EEE so pervasive this year.

According to Catherine Brown, the head epidemiologist at the Massachusetts Department of Public Health, there are several reasons as to why 2019 saw an unusually high amount of EEE cases in the state, including wet and rainy weather, climate change, and even the possible introduction of a new strain of EEE from Florida. Since EEE-carrying mosquitoes rely on areas of standing water in order to reproduce, officials with the Norfolk County Mosquito Control District are now working to eliminate urban and suburban locations where rainwater pools. In addition to standing water in urban areas, the primary EEE-carrying mosquito species in Massachusetts, C. perturbans, reproduces in rural marshes located near human dwellings. This has prompted the district to perform aerial larvicide drops over marshy areas, which will create an inhospitable environment for mosquitoes next spring. The district is also planning a more aggressive campaign to raise awareness among the public concerning the elimination of standing water in residential areas. In order to reproduce, EEE-carrying mosquitoes rely heavily on standing water that collects in clogged gutters, miniature swimming pools, solo cups, aluminum cans, flower pots, bird baths, bottle caps, and other containers frequently found on lawns during the warmer months. Eliminating these standing water sources before the spring season arrives will make urban mosquito control efforts more effective throughout the summer and fall in Massachusetts.

Do you diligently remove standing water sources from your lawn throughout the year?