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Mass Health Officials Say State’s 8th West Nile Virus Case Reported in Middlesex County

Despite cooling temperatures, state health officials are once again warning everyone in Middlesex County to take precautions against mosquito bites after more cases of an insect-borne virus were reported.

The Massachusetts Department of Public Health (DPH) announced last week the eighth human case of West Nile virus (WNV) in the state this year. The individual is a male in his 50s who was exposed to WNV in Middlesex County.

Twenty-seven communities in Essex, Middlesex, Norfolk, and Suffolk counties are at high risk and 71 communities are at moderate risk.

The Burlington Board of Health last reported the town’s risk level as “high”.

“The risk from WNV is starting to decline but some risk will remain until the first hard frost,” said Acting Public Health Commissioner Margret Cooke. “Although people over the age of 50 are at greater risk from West Nile virus, all ages can be affected. People should remember to take steps to prevent mosquito bites anytime they are outdoors.”

In 2020, there were 11 human cases of WNV infection identified in Massachusetts. WNV is usually transmitted to humans through the bite of an infected mosquito. Most people infected with WNV will have no symptoms, MassDEP says. When present, WNV symptoms tend to include fever and flu-like illness. In rare cases, more severe illness can occur.

By taking a few, common-sense precautions, people can help to protect themselves and their loved ones:

  • 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. Although it may be difficult to do 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, permethrin, picaridin, IR3535 or oil of lemon eucalyptus according to the instructions on the product label.
  • 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 getting rid of items that hold water. Check gutters, drains, unused flowerpots/containers, plastic toys, and wading pools; change water in birdbaths frequently. During the summer, mosquito larvae can complete their development in water within a week.
  • Properly maintain unused swimming pools. Mosquitoes commonly lay eggs in neglected swimming pools and water in loose fitting pool covers or tarps.
  • 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.

For further information, log onto the MDPH web site at If residents have any questions about mosquitoes or how to control them, contact the East Middlesex Mosquito Control Project at 781-899-5730 or the Burlington Board of Health at 781-270-1955.