For Immediate Release - July 07, 2016

State Public Health Officials Announce Season’s First Positive Mosquito Samples for West Nile Virus

Residents urged to use bug spray, personal protection to avoid getting bitten

BOSTON — The Massachusetts Department of Public Health (DPH) announced today that West Nile virus (WNV) has been detected in mosquitoes in Massachusetts for the first time this year. The presence of WNV was confirmed by the Massachusetts State Public Health Laboratory today in three mosquito samples which were collected on July 1 in the City of Worcester. No human or animal cases of WNV or Eastern Equine Encephalitis (EEE) have been detected so far this year. There is no elevated risk level or risk level change associated with this finding.

“This is an expected finding at this time of year and given the heat and dry conditions we have been experiencing, we are expecting to see more and more WNV activity,” said DPH State Epidemiologist Dr. Al DeMaria. “Tools for prevention include using a mosquito repellent with an EPA-registered ingredient according to the directions on the label, wearing clothing to reduce exposed skin when weather permits, draining standing water to prevent mosquito breeding and repairing window screens to keep mosquitoes out of your home.”

WNV is usually transmitted to humans through the bite of an infected mosquito. In 2015, there were ten human cases of WNV infection identified in Massachusetts. While WNV can infect people of all ages, people over the age of 50 are at higher risk for severe disease. Most people infected with WNV will have no symptoms. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

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 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 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

Water troughs and buckets 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, llama and alpaca owners should keep animals in indoor stalls at night to reduce their risk of exposure to mosquitoes. Owners should also 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 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, can be accessed from the Arbovirus Surveillance Information web page at www.mass.gov/dph/mosquito or by calling the DPH Epidemiology Program at 617-983-6800.

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