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Oh Swat! State’s Mosquito Population is High and So is Risk of Disease

September 21, 2021

A wet summer that included heavy and prolonged rains from two tropical storms in August have created widespread areas of standing water, breeding grounds for mosquitoes. With that comes another concern: West Nile and Eastern Equine Encephalitis viruses, both transmitted through the bite of an infected mosquito.

The Department of Public Health says West Nile virus is the most common mosquito-borne disease in the United States and reemerges every year in Connecticut, typically in late summer. Already, mosquitoes trapped in 34 Connecticut towns have tested positive for the virus.

The towns where mosquitoes have tested positive for the virus are: Branford, Bridgeport, Darien, Easton, Fairfield, Glastonbury, Greenwich, Hamden, Litchfield, Manchester, Middlefield, Milford, Meriden, New Britain, New Canaan, New Haven, Newington, Newtown, North Branford, North Haven, Norwalk, Orange, Ridgefield, Somers, South Windsor, Southington, Sprague, Stamford, Stratford, Waterford, West Haven, Westport, Wethersfield, Wilton.

DPH says three people so far have tested positive for a human form of West Nile, in Bridgeport, West Haven and Hartford. All three are recovering from the virus, which can initially mimic the flu. So far there are no reported cases of EEE.

Drought conditions in 2020 meant no reported human infections of either West Nile and EEE in Connecticut, but 2019 saw a record year, with 10 eastern states reporting 38 human cases and 15 fatalities. Four of the human cases and three of the deaths occurred in southeastern Connecticut.

“Certainly the more mosquitoes there are, the more risk there is,” says Dr. Virginia Bieluch, an infectious disease specialist at The Hospital of Central Connecticut. “But I think everybody should be taking precautions. If you don’t need to sit outside at dusk you probably want to avoid it right now.”

How EEE and West Nile Virus Spread

Mosquitoes can get either virus after biting an infected bird. Mosquitoes sometimes transmit the virus to horses and other animals, but rarely to humans. West Nile, first identified in the United States in 1999 in Queens, N.Y., is passed by mosquitoes from bird to bird. Sometimes, a mosquito will infect humans or animals.

What Are EEE and West Nile Virus Symptoms?

Both diseases start with headache, fever and body aches. West Nile characteristics can include enlarged lymph nodes and a rash on the chest or stomach. Severe cases of EEE include encephalitis, or swelling of the brain. As it progresses, EEE can cause disorientation, seizures and coma. About a third of EEE patients die from the disease. Survivors can have mild to severe brain damage.

State public health officials say it takes from four to 10 days after a bite from an infected mosquito to develop symptoms.

How to Protect Yourself

All the rules of mosquito-bite avoidance apply here. Remember that mosquitoes carrying West Nile or EEE reach peak activity just after dawn and an hour before dusk. Insect season lasts until the first frost.

Some tips from the Centers for Disease Control and Prevention:

  • Use Insect Repellent: Look for one of these active ingredients: DEET, Picaridin, oil of lemon eucalyptus, IR3535, para-menthane-diol or 2-undecanone.
  • Wear long-sleeve shirts, long pants: When extra protection is needed, treat clothing with permethrin, an insecticide that kills or repels mosquitoes. (Do not spray directly on skin.)
  • Control mosquitoes: Make sure screens on windows and doors have no tears and use air conditioning. Eliminate standing water, where mosquitoes lay eggs. That includes flower pots, buckets and planters. Change water in bird baths at least twice and check gutters for blockages and backed-up water.