Press Releases

Header for mosquito program website.


Risk of West Nile Virus Continues Positive Mosquitoes Detected in 14 Connecticut Towns

EEE Positive Mosquitoes Detected in 2 Towns

New Haven, CT – The State Mosquito Management Program announced today that mosquitoes collected in 14 Connecticut towns have tested positive for West Nile virus (WNV). So far this season, the Connecticut Agricultural Experiment Station (CAES) has detected WNV-infected mosquitoes in: Branford, Bridgeport, Darien, Greenwich, Guilford, Hartford, New Britain, New Canaan, New Haven, Newington, Norwalk, Stamford, Waterbury, and Wethersfield. In addition, mosquitoes carrying eastern equine encephalitis (EEE) virus have been identified in two towns this season: Hampton and Stonington. There are no reported human or equine cases of EEE virus but 1 human case of WNV infection has been reported in Connecticut so far this year.

“We continue to see increases in the number of mosquitoes carrying West Nile virus, especially in coastal Fairfield and New Haven counties and in the greater Hartford area,” said Dr. Philip Armstrong, Medical Entomologist at the CAES. “In addition, the detection of EEE virus in two towns in eastern Connecticut requires continued vigilance. We will continue to monitor the situation and trap mosquitoes until the end of the season in October."

"Historically, August and September are the months of greatest risk for acquiring West Nile virus and EEE infection," said Dr. Jocelyn Mullins, State Public Health Veterinarian, Department of Public Health. "Now is the time to take precautions to prevent mosquito bites."

To reduce the risk of being bitten by mosquitoes residents should:

  • 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 mosquito repellent, according to directions, when it is necessary to be

West Nile virus is the most common mosquito-borne disease in the United States and reemerges every summer in Connecticut. One human case of WNV-associated illnesses has been reported in Connecticut so far this season. Before 2020, 158 cases of West Nile virus were reported in Connecticut, of which 4 were fatal.

Eastern equine encephalitis is a rare but serious mosquito-borne viral disease in people and horses. On average, there are 6 human cases reported each year in the United States. The mortality rate of hospitalized patients is one-third and approximately one-half of survivors become disabled due to
neurological damage. The first locally-acquired human case of EEE occurred in Connecticut during 2013 and last year, there were 4 human cases of which 3 were fatal.

The State of Connecticut Mosquito Management Program is a collaborative effort involving the Department of Energy & Environmental Protection, the Connecticut Agricultural Experiment Station, the Department of Public Health, the Department of Agriculture, and the University of Connecticut Department of Pathobiology and Veterinary Science. These agencies are responsible for monitoring the potential public health threat of mosquito-borne diseases.

The CAES maintains a network of 108 mosquito-trapping stations in 87 municipalities throughout the state. Mosquito traps are set Monday through Thursday nights at each site every ten days on a rotating basis. Mosquitoes are grouped (pooled) for testing according to species, collection site, and date. Positive findings are reported to local health departments and on the CAES website.

For information on West Nile virus and how to prevent mosquito bites, visit the Connecticut Mosquito Management Program website.