CT Begins Testing For Mosquito-Borne Viral Diseases

CONNECTICUT — The State of Connecticut Mosquito Management Program has begun monitoring mosquitoes for the presence of viruses that can cause illness in people, including West Nile virus and eastern equine encephalitis virus.

The mosquito trapping and testing program, coordinated by the Connecticut Agricultural Experiment Station, began Tuesday and will continue through the end of October.

Last season, WNV was detected in 208 mosquito pools from 43 towns in all eight counties in Connecticut. Six confirmed human cases of WNV infection were reported from Fairfield, Hartford, and New Haven Counties with dates of onset from Aug. 20 to Oct. 10. State scientists will be trapping and testing mosquitoes from 108 locations statewide from now until October, according to Philip Armstrong, medical entomologist at CAES.

WNV occurs every summer in the Northeast and has become the main cause of mosquito-borne illness in this region since it was first introduced into the New York City area in 1999.

"Typically, West Nile virus activity peaks from July – September, especially in densely-populated areas of lower Fairfield and New Haven Counties, and the Hartford metropolitan area. Seasonal transmission of EEE virus, in contrast, occurs more sporadically with focal areas located in rural areas of eastern Connecticut," Armstrong said.

During 2021, EEE virus was detected in two mosquito pools collected from one town in New London County. There were no EEE infections reported in humans or horses. EEE is a rare but serious illness in humans with 4 to 8 cases reported in a typical year in the U.S. During 2019, the number of confirmed human cases rose to 38 with four cases, including three fatalities, occurring in Connecticut.

For Connecticut residents who wish to avoid being bitten by mosquitoes, CAES suggests:

• 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 to protect small babies when outdoors.
• Consider the use of an EPA-registered mosquito repellent, according to directions, when it is necessary to be outdoors.