Ledge Light Health District announced Friday that mosquitoes trapped in Waterford and Groton have tested positive for eastern equine encephalitis.

This is in addition to the previously announced positive mosquitoes in Lyme, Old Lyme, Groton, Ledyard, North Stonington and Stonington. The mosquitoes trapped in Waterford and Groton are primarily bird-biting.

EEE is a rare but serious disease caused by a virus that is transmitted by mosquitoes. Historically, the virus has been found in trapped mosquitoes in Connecticut but there has been only one human case before this year, officials have said.

Residents who live in or near towns where the EEE virus has been found in mosquitoes and/or where there has been a confirmed case of EEE involving a human, horse or bird are advised to take precautions to avoid mosquito bites, including:

• Be sure door and window screens are tight-fitting and in good repair.

• While outdoors, wear shoes, socks, long pants and long-sleeved shirts. Clothing material should be tightly woven.

• Use mosquito netting if sleeping outdoors.

• Consider using mosquito repellent when it is necessary to be outdoors and always use them according to label instructions. The most effective repellents contain DEET or Picaridin. Oil of lemon eucalyptus also is effective for brief periods of exposure. When using DEET, use the lowest concentration effective for the time spent outdoors — for example, 6 percent lasts approximately two hours and 20 percent for four hours — and wash treated skin when returning indoors. Do not apply under clothing, to wounds or irritated skin, the hands of children or to infants less than 2 months old.

Measures to reduce mosquitoes around the home include:

• Dispose of water-holding containers, such as ceramic pots, used tires, and tire swings, and unclog gutters.

• Drill holes in the bottom of containers such as those used for recycling.

• Change water in bird baths on a weekly basis.

• Clean and chlorinate swimming pools, and cover pools when not in use.

• Use landscaping to eliminate areas where water can collect on your property.

Additional resources for information on EEE and mosquito management can be found at bit.ly/CTmosquito.