First WNV-Positive Mosquito Pool of Season


Hartford – The State Mosquito Management Program today announced that mosquitoes trapped in Norwalk on July 2, 2013 have tested positive for West Nile virus (WNV). These results represent the first positive mosquitoes identified in the state by the Connecticut Agricultural Experiment Station (CAES) this year. Connecticut residents are reminded to protect themselves from mosquito bites and mosquito-borne diseases.

“The West Nile virus season has started,” said Dr. Theodore Andreadis, Chief Medical Entomologist at the CAES. “Early- to mid-July is when we typically start to see an increase in infected mosquitoes and is a reminder for people to take steps to protect themselves from mosquito bites now through September.”


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 most 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 activity varies each year and is difficult to predict. In 2012, WNV-positive mosquitoes were trapped in 44 municipalities; the first were trapped in Stamford on June 27. In addition, last year 21 Connecticut residents were identified with WNV infections. That is the highest number of human cases of WNV identified in Connecticut since surveillance began in 2000.


Nationally, there were more reported cases of WNV last season than in previous years. During 2012, 5,674 human cases of WNV-related illness and 286 fatalities were reported in 48 states by the Centers for Disease Control and Prevention. The largest numbers of WNV-related illnesses reported in humans were in the southern and mid-western parts of the country.


Monitoring and risk assessment for WNV emphasizes mosquito trapping and testing results. 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.  Each pool is tested for the presence of viruses of public health importance. Positive findings are reported to local health departments and on the CAES website at


For information on West Nile virus and what you can do to prevent getting bitten by mosquitoes, visit the Connecticut Mosquito Management Program website at


Mosquito pools that test positive for WNV and EEE, as well as human cases of these illnesses, will also be posted on the Connecticut Mosquito Management Program website.