June 24, 2022: The Centers for Disease Control and Prevention has listed Fairfield, Hartford, New London, Middlesex, Tolland, and Windham Counties in Low/Green the as part of its COVID-19 Community Levels Map. Only Litchfield, Middlesex and New Haven County are listed in the Medium/Yellow category. Residents who live in the Medium /Yellow counties who are at a high risk for severe illness, should talk to their health care provider about whether to wear a mask and take other precautions. These residents should stay up to date with their COVID-19 vaccines and get tested if they have symptoms. Visit the CDC COVID-19 Community Levels Map for updates.


Center for Vector Biology & Zoonotic Diseases                          

The Connecticut Agricultural Experiment Station The Connecticut Agricultural Experiment Station

Dr. Philip Armstrong

Phone: 203-974-8510 

Email: philip.armstrong@ct.gov

Dr. Theodore Andreadis

Phone: 203-974-8440

Email: theodore.andreadis@ct.gov

State Reports Positive Mosquitoes for West Nile Virus in Stamford

First WNV-Positive Mosquito Pool of Season


New Haven – The State Mosquito Management Program today announced that mosquitoes trapped in Stamford on July 6, 2016 tested positive for West Nile virus (WNV).  These results represent the first WNV positive mosquitoes identified in the state by the Connecticut Agricultural Experiment Station (CAES) this year. All mosquitoes collected in the state have tested negative for Zika virus.


"The West Nile virus season has started," said Dr. Philip Armstrong, Medical Entomologist at the CAES.  "Early- to mid-July is when we typically first detect WNV infection in mosquitoes and we anticipate further build-up of the virus from now through September."


“This serves as a reminder for people to take steps to protect themselves from mosquito bites,” said Dr. Theodore Andreadis, Director of the CAES. “Although there is much concern about the possible introduction of Zika virus, we should not lose sight of mosquito-borne diseases like WNV that are already established in Connecticut and reemerge every summer.”


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 outdoors.


    West Nile virus has been detected in the state every year since 1999. During 2015, WNV was detected in mosquitoes collected at trap sites in 24 towns.  In addition, 10 confirmed human cases of WNV were reported and were residents of Bridgeport (6), Fairfield (1), Milford (1), New Haven (1), and Shelton (1).


    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 91 mosquito-trapping stations in 72 municipalities throughout the state. Mosquito traps are set Monday – 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 at http://www.ct.gov/caes/mosquitotesting.


    For information on WNV and other mosquito-borne viruses and how to prevent mosquito bites, visit the Connecticut Mosquito Management Program Web site at www.ct.gov/mosquito.