BOSTON — The Massachusetts Department of Agricultural Resources (MDAR), State Reclamation and Mosquito Control Board (SRMCB), and the Massachusetts Department of Public Health (DPH) recently announced that aerial spraying for mosquitoes will take place in specific areas of Plymouth County and a small part of Bristol County.

Spraying is expected to begin on Monday, August 10, and continue over several evenings. However, the ability to spray is weather dependent and the schedule may change. So far this year, 12 communities in southeastern Massachusetts have been found by DPH to be at moderate to critical risk for the Eastern Equine Encephalitis (EEE) virus.

The 25 communities in the spray zone are Bridgewater, Carver, Duxbury, East Bridgewater, Halifax, Hanover, Hanson, Kingston, Lakeville, Marion, Mattapoisett, Middleborough, Norwell, Pembroke, Plymouth, Plympton, Rochester, Rockland, Wareham, West Bridgewater, and Whitman in Plymouth County, and Acushnet, Easton, Raynham, and Taunton in Bristol County. The exact locations where spraying will occur are subject to change, and the final spray map for each day of spraying will be available each morning ahead of the spray operations.

The SRMCB with the assistance of MDAR will conduct and monitor aerial spraying in specific areas of Plymouth County and a small part of Bristol County. Residents are encouraged to visit the Massachusetts Aerial Mosquito Spray Map webpage for the latest updates on spraying in their communities. Officials will continue to monitor the area over the next two weeks and may conduct a second round of spraying to achieve maximal effectiveness.

EEE is a rare but serious and potentially fatal disease that can affect people of all ages. On August 3, DPH announced this year’s first human case of EEE virus infection, a male under the age of 18 who was exposed to EEE in Plymouth County. Last year, the Commonwealth experienced its most active EEE season since 1956, with 12 human cases and 6 deaths.

“As several communities in Southeastern Massachusetts are at elevated risk for EEE and this season’s first human case has been confirmed, the Commonwealth is acting to protect the public by conducting aerial spray operations to reduce the population of mosquitoes that transmit the EEE virus,” said SRMCB Chair and MDAR Commissioner John Lebeaux. “While spraying for mosquitoes can reduce but does not eliminate the risk of EEE transmission, we ask the public to be vigilant and take care to follow personal protection practices.”

“EEE is rare, but it is a serious medical illness, and we remind residents of the need to protect themselves from mosquito bites as EEE activity increases,” said Public Health Commissioner Monica Bharel, MD, MPH. “The best prevention continues to be using mosquito repellent, wearing long sleeves and pants, weather permitting, and avoiding outdoor activity between the hours of dusk and dawn in the highest risk areas.”

The pesticide used is called Anvil 10+10, an EPA-registered product extensively tested and used in both ground-level and aerial spraying in the U.S. to control mosquitoes. Anvil 10+10 contains two ingredients: Sumithrin and Piperonyl butoxid. Sumithrin is rapidly inactivated and decomposes with exposure to light and air, with a half-life of less than one day in the air and on plants. In soil, it degrades rapidly and has proven to be extremely effective in killing mosquitoes worldwide for over 20 years. Piperonyl butoxide serves to increase the ability of Sumithrin to kill mosquitoes.

There are no health risks expected during or after spraying. No special precautions are recommended; however, residents can reduce exposure by staying indoors during spraying. Aerial spraying is not expected to have any impacts on surface water or drinking water.

Aerial spraying will be conducted in the nighttime hours when fish are less likely to be at the surface feeding and honeybees are most likely to be in their hives. However, owners should cover small ornamental fishponds during the night of spraying. While it is not necessary to bring animals indoors during spraying, keeping pets inside will minimize the risk of exposure.

Although the aerial spray is considered necessary to reduce human risk, it will not eliminate it. Residents must continue to protect themselves from mosquito bites by staying indoors during peak mosquito hours, applying insect repellent when outdoors, draining standing water where mosquitoes breed, repairing screens in doors and windows, and protecting pets.

— Massachusetts Department of Public Health

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