West Nile virus in Connecticut: what to do?

CONNECTICUT – The mosquitoes that bring the dreaded West Nile virus to Connecticut every summer are back, and they’re ahead.

Connecticut Agricultural Experiment Station field crews trapped the first positive bug for the virus in Milford on June 21.

Philip Armstrong, virologist and medical entomologist in the Department of Environmental Sciences at the Center for Vector Biology & Zoonotic Diseases at DOGS, said his colleagues usually do not encounter insects carrying WNV until early or mid-July.

Armstrong said we have no more control over mosquito infestations and subsequent WNV outbreaks than we have over the weather.

West Nile virus has been detected in Connecticut every year since its introduction to North America in 1999, when it “exceeded all of our expectations,” Armstrong said. “It reappears every summer, it’s extremely reliable, and the levels of viral activity fluctuate a lot from year to year, and it really depends on the summer weather.”

If it’s a hotter-than-average summer, the state will face a heavy toll of WNV cases, Armstrong said. Last season, West Nile virus was detected in 143 mosquito ponds in 21 cities in Fairfield, Hartford and New Haven counties, with eight human cases. In 2019, CAES followed WNV in 82 mosquito samples from 23 cities, and one human case was reported. The previous year, 158 cases of West Nile virus had been reported in Connecticut, including four fatalities.

There is no vaccines to prevent or drugs to treat WNV in humans, according to the Centers for Disease Control and Prevention. Most people with the disease do not feel sick, but about one in five people who get it develop a fever and other symptoms. About one in 150 infected people develop serious, sometimes fatal illness.

“And the next few weeks and months of that kind of hot weather that we’re experiencing right now is the perfect weather for West Nile virus and the mosquito that carries it. He really likes hot, hot, hot weather,” Armstrong said. “We kind of hold our breath to see what’s going on.”

Some municipalities cannot wait and have become intransigent in their fight against insects. These towns have started treating storm sewers, where mosquitoes tend to breed, with larvicides to kill the young. Armstrong said the best technological solution would be to use a large area aerial larvicide, but this is impractical as mosquitoes infest urban and suburban areas.

“There aren’t a lot of great options for mosquito control,” the entomologist told Patch. “We expect it to continue to spread and amplify in the weeks and months to come.”

The traditional breeding ground for mosquitoes has been the communities along the Interstate 95 corridor, from lower Fairfield County and lower New Haven County, from New Haven and Hartford to Greenwich. Knowing what they know now, other CAES teams return to Milford to do some additional trapping, according to Armstrong, but the bug hunt can be a bit of a shit hunt.

“It’s a little unpredictable when and where it resurfaces,” he said.

What scientists know is how to reduce the risk of WNV infection. CAES officials advise residents to take the following steps to reduce the risk of being bitten by mosquitoes:

• Minimize the time spent outdoors between dusk and dawn when mosquitoes are most active.
• Make sure the screens on doors and windows are properly fitted and in good condition.
• Wear shoes, socks, long pants, and a long-sleeved shirt when you are outside for long periods of time or when mosquitoes are more active. Clothing should be light in color and made of tightly woven materials that repel mosquitoes from the skin.
• Use a mosquito net when sleeping outdoors or in a non-mosquito net and to protect infants outdoors.
• Consider using an EPA approved insect repellant and apply it according to directions when it is necessary to be outdoors.