State Health Officials Detect More EEE-Positive Mosquitoes in Southeastern Massachusetts

BOSTON — The Massachusetts Department of Public Health (DPH) today announced that Eastern Equine Encephalitis (EEE) has been found in mammal-biting mosquitoes in the town of Carver. The mosquitoes were collected on July 10 and tested at the State Laboratory Institute.

Today’s findings follow the announcement yesterday that four EEE-positive mosquito samples had been detected in the town of Easton. No additional infected mosquitoes have been found in Easton, despite extensive testing of 26 extra mosquito samples collected there.

“We are concerned about finding more infected mammal-biting mosquitoes,” said DPH State Epidemiologist Dr. Al DeMaria “The fact that no more infected mosquitoes were found in Easton means that virus levels are not excessively high yet. However, we have to keep looking and testing to define the extent of the problem. In the meantime, the local mosquito control programs are doing their jobs and we all need to help them by taking precautions to avoid mosquito bites. Cover up, use repellent and avoid the peak mosquito hours of dusk to dawn.”

The risk level for mosquito-borne illness remains at “moderate” in Carver. The recent detection of EEE-infected mosquitoes in Easton resulted in the raising of the risk level to “high” in the towns of Easton, Raynham and Taunton.

There have been no human cases of West Nile virus (WNV) or EEE so far this year. There were two cases of EEE in August of last year acquired in Massachusetts; a fatal case in a Bristol County man and an infection in a tourist from out of state. EEE activity in both 2010 and 2011 raised public concern and prompted DPH to work with a panel of experts to evaluate and enhance the state’s surveillance and response program. EEE is spread to humans through the bite of an infected mosquito. EEE is a serious disease in all ages and can even cause death.

People have an important role to play in protecting themselves and their loved ones from illnesses caused by mosquitoes.

Avoid Mosquito Bites

• Apply Insect Repellent when Outdoors. Use a repellent with 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.
• 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 any unused flowerpots and wading pools, and change water in birdbaths frequently.
• Install or Repair Screens. Keep mosquitoes outside by having tightly-fitting screens on all of your 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 provide excellent mosquito breeding habitats and should be flushed out at least once a week during the summer months to reduce mosquitoes near paddock areas. Horse owners should keep horses in indoor stalls at night to reduce their risk of exposure to mosquitoes. If an animal is diagnosed with WNV or EEE, owners are required to report to DAR, Division of Animal Health by calling 617-626-1795 and to the Department of Public Health (DPH) by calling 617-983-6800.

More information, including all WNV and EEE positive results from 2012, can be found on the Arbovirus Surveillance Information web page at www.mass.gov/dph/wnv or by calling the DPH Epidemiology Program at 617-983-6800. The findings of the DPH Eastern Equine Encephalitis Expert Panel can be found here.

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