The State Mosquito Management Program announced Thursday that two Connecticut residents have tested positive for West Nile virus (WNV) infection. These are the first human cases of WNV associated illness identified in Connecticut this season. Both are residents of Bridgeport. 

Image/National Atlas of the United States
Image/National Atlas of the United States

One patient, between 40-49 years of age, became ill during the third week of August with meningitis. The other patient, between 70-79 years of age, became ill during the fourth week of August with encephalitis. The illnesses were characterized principally by fever, nausea, vomiting and weakness. Both patients were hospitalized and have been discharged. Laboratory tests confirmed the presence of antibodies to WNV. They did not travel out of the state prior to onset of illness.

“The identification of Connecticut residents with West Nile virus associated illness that required hospitalization underscores the potential seriousness of infection,” said Department of Public Health veterinarian, Dr. Randall Nelson. “Using insect repellant, covering bare skin and avoiding being outdoors during the hours of dusk and dawn are effective ways to help keep you from being bitten.” 

“We continue to have weather conditions that are favorable for the mosquitoes that transmit West Nile virus,” said Dr. Philip Armstrong, Medical Entomologist at the CAES. “These mosquitoes are most abundant in urban and suburban areas with dense human populations. West Nile virus positive mosquitoes have been identified in Bridgeport starting August 3rd and most recently on August 27th.” 

During 2015, WNV-positive mosquitoes have now been identified in 20 towns: Bridgeport, Cheshire, Chester, Darien, East Haven, Glastonbury, Greenwich, Groton, Guilford, Hartford, New Haven, Norwalk, Stamford, Stonington, Stratford, Waterford, West Haven, Westport, Wethersfield and Wilton. Of the 20 towns, 15 are located along Long Island Sound in Fairfield (8), New Haven (4) and New London (3) counties. Importantly, the numbers of WNV infected mosquitoes responsible for transmission of the virus to people that have been trapped recently exceed the historical weekly averages.

During 2014, WNV-positive mosquitoes were identified in a total of 15 towns. Six people were reported with WNV-associated illnesses. There were no fatalities; however, five people were hospitalized.

Exposure to mosquitoes and the risk of acquiring WNV infection varies by season and geographic region. In Connecticut, the risk is highest during August and September and typically subsides in October as mosquitos die off due to lower temperatures.