Mosquito sample in Pittsfield tests positive for EEE


Updates with new information ...

PITTSFIELD -- The state Department of Public Health has detected Eastern equine encephilitis in a mosquito sample from Pittsfield. It's the first time EEE has been confirmed in mosquitoes in Berkshire County.

A rare, but deadly disease, there have been no human cases of EEE reported in Massachusetts this year.

The mosquito sample was collected Monday in Pittsfield in the Williams Street area. City officials said insecticide spraying will start after dark on Friday and continue throughout the rest of the weekend after dark and before dawn.

According to the DPH, spraying will take place in the areas of Williams, Elm, Newell, and East streets and Dorchester and Dalton avenues.

Spraying is the "most effective way to reduce the adult mosquito population" in an urban community like Pittsfield, according to the city's public health director, Meredith O'Leary.

O'Leary said sporadic findings of EEE in mosquitoes "occur across Massachusetts and do not necessarily represent significant risk of disease. Only southeastern Massachusetts has seen significant activity so far this year."

While Pittsfield is classified by the DPH as a low-risk area for human contraction of EEE at this point, parts of southeastern Massachusetts - towns such as Canton, Raynham and Taunton - have been classified as high-risk areas.

Last year, two people contracted EEE in Massachusetts; one, a case in Bristol, was fatal.

"Since testing [mosquitoes] is relatively new in Pittsfield, it is very hard to interpret the data we are receiving from the pools of mosquito specimens we are sending out for testing," said O'Leary.

Absent historical data, she said, there is no way to determine if the presence of EEE is new "or has always been present, to an extent."

According to the state Department of Health, since EEE was first identified in the state in 1938, fewer than 100 cases in humans have been diagnosed. More than 60 percent of those cases have been discovered in Plymouth and Norfolk counties. Outbreaks of EEE usually occur in the state every 10 to 20 years.

EEE is spread to humans through the bite of an infected mosquito.

Symptoms of EEE include at fever, often between 103 and 106 degrees, stiff neck, headache and lack of energy and show up three to 10 days, according to the DPH. The most serious complication is inflammation and swelling of the brain. The disease gets worse quickly and some patients may go comatose within a week.

Most at risk of developing serious complications are those under 15 and over 50.

Tests already have confirmed the presence of West Nile Virus in mosquitos in Pittsfield and in the Ashley Falls section of Sheffield. West Nile was first detected in Berkshire County last September. West Nile typically results in flu-like symptoms in people.

Avoiding EEE and WNV ...

  • Avoid outdoor activity between dusk and dawn, when mosquitos are most active.
  • When outdoors, use repellent, wear long pants, socks and long-sleeved shirts.
  • Drain standing water, which mosquitos could use to lay eggs. Check rain gutters and drains; empty any unused flowerpots and wading pools, and frequently change water in birdbaths.
  • Install or repair screens.
  • Download the Massachusetts Department of Public Health fact sheet to learn more about EEE.
  • -- Source: Massachusetts DPH

    The Pittsfield Board of Health's full statement

    Pittsfield Board of Health's Public Health Notice: Confirmed Eastern Equine Encephalitis (EEE) Virus in Pittsfield

    PITTSFIELD -- The Massachusetts Department of Public Health (MDPH) announced today that Eastern Equine Encephalitis virus has been detected in bird-biting mosquitoes collected from Pittsfield, MA.

    EEE is a rare but serious illness spread by the bite of an infected mosquito. While EEE can infect people of all ages, those under15 years of age or over 50 years of age are at greatest risk for serious illness.

    The infected mosquito was found among a group of specimens that were trapped in the Williams Street area. The city plans to heavily treat that area with insecticides. Larvacide will be used to reduce the mosquito populations at the breeding site and adulticide will be used to reduce the adult population when they are active.

    The adulticide will be applied by a truck mounted spray nozzle beginning after dark on Friday (today) and continue in the evenings and before dawn throughout the weekend. "This source of application is the most effective way to reduce the adult mosquito population in a well-developed urban area such as Pittsfield," said Merridith O'Leary, Pittsfield's Public Health Director.

    "Sporadic findings of EEE in bird-biting mosquitoes can occur across Massachusetts and do not necessarily represent significant risk of disease," she continued. "Only southeastern Massachusetts has seen significant EEE activity so far this year. However, this is a good reminder that it is important for people to practice personal prevention to protect themselves."

    The City of Pittsfield has only been part of the Berkshire County Mosquito Control Project since the middle of last year. Prior to that, very few mosquito specimens were ever tested from Berkshire County. "Since testing is relatively new in Pittsfield, it is very hard to interpret the data that we are receiving from the pools of mosquito specimens that are being sent for testing," O'Leary said. "Without any historical data, we do not know if the presence of the West Nile Virus and the EEE virus in our mosquitos is new or has always been present to an extent."

    The Pittsfield Board of Health and Berkshire County Mosquito Control Project will continue to work closely with the MDPH and other agencies. Locally, the board will continue efforts to provide targeted education programs, health fairs, distribution of fact sheets on EEE and informati0n on how to reduce exposure.

    It is very important that city residents use precautions to protect themselves and their loved ones.

    Avoid Mosquito Bites

    • Be Aware of Peak Mosquito Hours - The hours from dusk to dawn are peak biting times for many mosquitoes. The Department of Public Health strongly recommends that all outdoor activities be curtailed during the hours surrounding dawn and dusk. If you are outdoors at any time and notice mosquitoes around you, take steps to avoid being bitten by moving indoors, covering up and/or wearing repellant.
    • Clothing Can Help reduce mosquito bites. Although it may be difficult when it's hot, wearing long-sleeves, long pants and socks when outdoors will help keep mosquitoes away from your skin.

    Apply Insect Repellent when you go outdoors. Use a repellent with DEET (N, N-diethyl-m-toluamide), permethrin, picaridin (KBR 3023), IR3535 or oil of lemon eucalyptus [p-methane 3, 8-diol (PMD)] 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. Permethrin products are intended for use on items such as clothing, shoes, bed nets and camping gear and should not be applied to skin.

    Mosquito-Proof Your Home

    • Drain Standing Water - Many mosquitoes lay their eggs in standing water. Limit the number of places around your home for mosquitoes to breed by either draining or getting rid of items that hold water. Check rain gutters and drains. Empty any unused flowerpots and wading pools, and change water in birdbaths frequently.
    • Install or Repair Screens - Some mosquitoes like to come indoors. Keep them outside by having tightly-fitting screens on all of your windows and doors.
    Information about EEE and reports of current and historical EEE virus activity in Massachusetts can be found on the MDPH website at


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