Boston — The Massachusetts Department of Agricultural Resources (MDAR), State Reclamation and Mosquito Control Board (SRMCB), and the Massachusetts Department of Public Health (DPH) today 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.  

For an FAQ regarding mosquito control and spraying, please visit the DPH website here. For information on Mosquito Control activities, please visit the State Reclamation and Mosquito Control Board (SRMCB) webpage.

All residents are reminded to use mosquito repellent any time they are outside, and those in high and critical risk communities are advised to schedule their outdoor activity to avoid the dusk to dawn hours to reduce exposure to the mosquitoes most likely to spread EEE. DPH recommends the following precautions.

Avoid Mosquito Bites

Apply Insect Repellent when Outdoors. Use a repellent with an EPA-registered ingredient (DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)] or IR3535) according to the instructions on the product label. DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age.

Be Aware of Peak Mosquito Hours. The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning in areas of high risk.

Clothing Can Help Reduce Mosquito Bites. Wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

Mosquito-Proof Your Home

Drain Standing Water. Mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or discarding items that hold water. Check rain gutters and drains. Empty unused flowerpots and wading pools, and change the water in birdbaths frequently.

Install or Repair Screens. Keep mosquitoes outside by having tightly-fitting screens on windows and doors.

Protect Your Animals

Animal owners should reduce potential mosquito breeding sites on their property by eliminating standing water from containers such as buckets, tires, and wading pools – especially after heavy rains. Water troughs should be flushed out at least once a week during the summer months and horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitoes. Owners should speak with their veterinarian about mosquito repellents approved for use in animals and vaccinations to prevent WNV and EEE. If an animal is suspected of having WNV or EEE, owners are required to report to MDAR, Division of Animal Health by calling 617-626-1795 and to DPH by calling 617-983-6800.

For information on Mosquito Control activities, visit the Massachusetts Department of Agricultural Resources  webpage at State Reclamation and Mosquito Control Board (SRMCB).

For other updates about EEE in Massachusetts, visit the DPH webpage www.mass.gov/eee.

Information including all West Nile virus and EEE positive results can be found on the Arbovirus Surveillance Information web page or by calling the DPH Epidemiology Program at 617-983-6800.

Read this press release in Spanish:

Funcionarios estatales anuncian planes para realizar una fumigación aérea contra los mosquitos en áreas del sureste de Massachusetts | Doc

Read this press release in Portuguese:

Autoridades Estaduais Anunciam Planos Para a Realização de Pulverização Aérea de Combate a Mosquitos em Partes da Região Sudeste de Massachusetts |Doc