NEW HAVEN, Conn. (WTNH) — The Connecticut Agricultural Experiment Station (CAES) has detected West Nile-infected mosquitoes in nearly 40 municipalities in the state so far in 2023.

Here’s when and where mosquitoes with a positive West Nile virus (WNV) were found, listed in alphabetical order, as of Sept. 19.

  • Bethel – 9/6
  • Branford – 7/27
  • Bridgeport – 8/7, 8/29
  • Colchester – 8/21
  • Danbury – 8/15
  • Darien – 8/8, 8/22, 8/29, 9/5, 9/6, 9/11
  • East Haddam – 7/31
  • East Haven – 7/27, 9/6
  • Fairfield – 7/27, 8/17
  • Glastonbury -8/29, 9/7
  • Greenwich – 8/9, 8/29, 9/11
  • Hartford – 8/23, 9/5
  • Hebron – 8/9
  • Killingworth – 8/17, 8/29
  • Ledyard – 9/13
  • Lyme – 9/6
  • Manchester – 8/8, 8/29
  • Mansfield – 8/22
  • Meriden – 9/7
  • Middlefield – 8/29
  • Milford – 8/23, 9/5
  • New Canaan – 8/2, 9/5
  • New Britain – 9/6, 9/13
  • New Haven – 9/13
  • North Stonington – 8/21
  • Norwalk – 8/7, 8/16, 8/28, 9/5
  • South Windsor – 7/27, 8/9
  • Stamford – 7/26, 7/31, 8/8, 8/10, 8/17, 8/21, 8/22, 8/29, 8/30, 9/7, 9/11
  • Stonington – 9/11
  • Tolland – 9/5
  • Trumbull – 9/7
  • Wallingford – 7/25, 8/7, 8/8
  • Waterbury – 7/25, 8/8
  • Waterford – 8/23
  • Westport – 8/28
  • Wethersfield – 7/17, 7/27, 8/9, 8/17, 8/29, 9/6
  • Willington – 8/22
  • Wilton – 8/15, 8/24, 9/6

Some places in Connecticut have picked up between 8 to 10 inches of rain in September so far. Standing water is a breeding ground for mosquitoes.

Rain totals for the month of September as of Sept. 21.

In addition to the rain, the warmer weather is keeping the mosquitoes around longer.

“We had a heat wave in early September, a couple of weeks ago, and that really helped fuel the number of mosquitoes we are collecting and the number of positive mosquitoes for these viruses,” said Dr. Philip Armstrong, the director of the mosquito monitoring program at CAES.

He said the numbers are starting to decline with recent cooler temperatures, but we really need a hard frost to end mosquito season. We typically see the first frost sometime in October.

Eastern Equine Encephalitis (EEE) virus 

The EEE virus is spread by adult mosquitoes and is found in rural towns. The risk of getting EEE is highest from late July through September, according to CAES.

Mosquitoes in the following towns have tested positive for EEE.

  • Hampton
  • Killingly
  • Mansfield
  • Stonington
  • Thompson
  • Tolland
  • Voluntown
  • Willington
  • Woodstock

How to protect yourself from WNV and EEE

The CAES urges residents to protect themselves from mosquito bites and mosquito-borne diseases. They offered the following advice:

  • Minimize time spent outdoors between dusk and dawn when mosquitoes are most active.
  • Be sure door and window screens are tight-fitting and in good repair.
  • Wear shoes, socks, long pants, and a long-sleeved shirt when outdoors for long periods of time or when mosquitoes are more active. Clothing should be light-colored and made of tightly woven materials that keep mosquitoes away from the skin.
  • Use mosquito netting when sleeping outdoors or in an unscreened structure, and protect infants when outdoors.
  • Consider the use of an EPA-approved mosquito repellent and apply it according to directions when it is necessary to be outdoors.
  • Empty out flower pots, buckets, or anything else that can hold water after each rain storm.

A look at 2022 stats

Last season, WNV was detected in 185 mosquito pools from 24 towns in six counties in Connecticut. Most WNV activity was detected in densely populated urban and suburban regions in Fairfield, Hartford and New Haven counties.

Seven human cases of WNV-related illness were reported with onset dates from Aug. 11, 2022, to Sept. 20, 2022.

Visit the Connecticut Mosquito Management Program website to learn more.