DPH Announces Three New Cases of West Nile Virus (WNV) Infection in Fairfield County
Residents Advised to Take Precautions Against Mosquito Bites Until the First Frost
The Connecticut Department of Public Health (DPH) today announced that three residents of Fairfield County have tested positive for West Nile virus (WNV) infection, bringing the total for this season to four human WNV cases. Two of the patients who are between the ages of 20-39 are residents of Danbury and Newtown, and became ill in the second week of August and are recovering. Of these two patients, one experienced headache and fever and the other was diagnosed with West Nile encephalitis. A third patient is a resident of Greenwich between the ages of 70-79 who became ill in the last week of August. This patient was hospitalized with West Nile encephalitis, and is recovering. Laboratory tests confirmed the presence of antibodies to WNV in all three patients.
“The last days of summer are a nice time of year to be outside and enjoy the weather, but as we do that I encourage everyone to take actions to prevent mosquito bites,” said DPH Acting Commissioner Deidre Gifford, MD MPH. “Mosquitoes are most active around the time of sunset and sunrise, and you can get very sick from West Nile Virus or other mosquito borne illnesses if you are not careful. This goes for any age, though anyone over the age of 60 is at greater risk. Using insect repellent, covering bare skin, and avoiding being outdoors during the hours of dusk and dawn are effective ways to help keep you from being bitten by mosquitoes. The risk of WNV doesn’t end until the first hard frost of fall.”
“Late summer-early fall is the critical time of year when West Nile virus reaches its peak in the mosquito population,” said Dr. Philip Armstrong, Medical Entomologist at the Connecticut Agricultural Experiment Station (CAES). “We strongly encourage residents throughout the state to take simple steps to prevent mosquito bites.”
West Nile virus is the most prevalent mosquito-borne disease in the U.S. and has been detected in Connecticut every year since 1999. Last year, CAES detected WNV in 82 mosquito samples from 23 towns and one human case was reported. Before 2020, 158 cases of West Nile virus were reported in Connecticut, of which 4 were fatal. For information on WNV human cases in CT, click here.
Most people (4 out of 5) infected with WNV do not develop symptoms. About 1 in 5 people who are infected develop West Nile fever, an illness which includes fever and other symptoms, such as body aches, joint pain, headache, or a rash. About 1 out of 150 infected people develop a severe illness affecting the central nervous system and approximately 1 out of 10 cases of severe illness are fatal.
Tips for reducing mosquitoes around homes
Mosquitoes require water for reproduction. The following are measures that can help reduce mosquitoes:
- Eliminate standing water suitable for mosquitoes. Dispose of water-holding containers, such as ceramic pots, used tires, and tire swings.
- Drill holes in the bottom of containers such as those used for recycling.
- Clean clogged roof gutters.
- Turn over objects that may trap water when not in use, such as wading pools and wheelbarrows.
- Change water in bird baths on a weekly basis.
- Clean and chlorinate swimming pools. When pools are not in use, use pool covers and drain when necessary.
Tips for avoiding mosquito bites when outdoors
Mosquitoes require a blood meal for reproduction. The following are measures that can help reduce bites from mosquitoes that feed on people:
- Minimize outdoor activities at dusk and dawn when mosquitoes are most active.
- Wear shoes, socks, long pants, and long-sleeved shirts. Clothing material should be tightly woven and loose fitting.
- Use mosquito netting when sleeping outdoors.
- Consider the use of CDC-recommended mosquito repellents, containing DEET, picaridin, oil of lemon eucalyptus, IR3535, or 2-undecanone, and apply according to directions, when it is necessary to be outdoors.
- When using DEET, use the lowest concentration effective for the time spent outdoors (for example, 6 percent lasts approximately two hours and 20 percent for four hours) and wash treated skin when returning indoors. Do not apply under clothing, to wounds or irritated skin, the hands of children, or to infants less than two months old.
- Be sure door and window screens are tight fitting and in good repair to avoid mosquito bites when indoors.
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 at
For information on West Nile virus and how to prevent mosquito bites, visit the Connecticut Mosquito Management Program Web site at www.ct.gov/mosquito