West Nile virus-infected mosquitoes found in 19 towns

Connecticut towns in which WNV-infected mosquitoes have been detected as of Aug. 2.
Connecticut towns in which WNV-infected mosquitoes have been detected as of Aug. 2.

Although none have been found in Wilton, the number of towns where mosquitoes infected with West Nile virus has increased to 19 towns in the past few weeks  — Bethany, Bridgeport, Darien, East Haven, Easton, Franklin, Greenwich, Hartford, Madison, Manchester, Meriden, New Canaan, New Haven, Stamford, Stratford, Waterbury, Waterford, West Haven, and Weston — according to the State Mosquito Management Program. The disease was identified by the Connecticut Agricultural Experiment Station (CAES) which tested mosquitoes collected from June 18 to Aug. 2.

The increase — West Nile virus was reported in mosquitoes in five towns as of July 10 — caused Gov. Dannel Malloy to issue a warning on Thursday.

“Based on the data we have so far this season, we know that cases of infected mosquitoes are rising at levels that are higher than normal, and that’s why it is essential for people to take extra precautions,” Malloy said. “If you need to be outside – and especially if you work outside – take action to protect yourself and your family.”

“We are seeing a major expansion and build-up of West Nile virus in the mosquito population” said Dr. Philip Armstrong, medical entomologist at the station. “We are also detecting the virus in human-biting mosquitoes comparatively early in the season, which substantially increases the risk of infection.”

He added this appears to be a very active season for West Nile virus. “Mosquito populations are building and will continue to do so, especially with the persistence of hot-muggy weather,” he said. “The surrounding states are also reporting early West Nile virus activity."

Dr. Raul Pino, commissioner of the Connecticut Department of Public Health, said mosquito-borne illness is a threat to take seriously, especially from now until well into September. “I ask everyone to prevent mosquito bites by eliminating standing water around your home, making sure your door and window screens are in good repair, and covering bare skin and using insect repellent when outside — especially at dusk and dawn when mosquitoes are most active.”

No human or horse cases have been reported with West Nile virus-associated illnesses in Connecticut this season. Since 2000, 134 human cases of West Nile virus have been diagnosed in Connecticut residents including three fatalities.

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, 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.

The CAES maintains a network of 91 mosquito-trapping stations in 72 municipalities throughout the state. There are two in Wilton. Mosquito traps are set Monday through Thursday nights at each site every 10 days on a rotating basis. Mosquitoes are grouped for testing according to species, collection site, and date.

In Wilton, 185 mosquitoes have been caught in the trap on Saunders Drive and one tested positive for Jamestown Canyon virus. More than 4,500 mosquitoes have been collected from Spectacle Road. Here, two tested positive for the same virus which infects the central nervous system and can cause brain inflammation — encephalitis — and meningitis, which is an inflammation of the membranes surrounding the brain and spinal cord.

Positive findings are reported to local health departments and online at ct.gov/caes/mosquitotesting.

For information on West Nile virus and how to prevent mosquito bites, visit  ct.gov/mosquito.