The Middletown Press (Middletown, CT)
Weather could affect West Nile virus
Buzz... Slap… Buzz… Slap Those summer sounds — mosquitoes humming, humans swatting — may fill our days and nights this year. It’s been wet and the winged bloodsuckers will have a lot of pools to breed in.
“There certainly are going to be a lot of them,” said Philip Armstrong, director of the state mosquito monitoring program at the Connecticut Agricultural Experiment Station in New Haven.
Whether it means a bad year for West Nile virus remains to be seen. Hot, sultry weather may unleash it. Downpours may keep it at bay.
“It’s sort of counterintuitive,” Armstrong said.
Which leaves local health departments trying to get the mosquito word out while a far more serious pandemic still buffets the world
“It’s not front-page news,” said Doug Hartline, Redding’s health officer. “People will pay more attention if there’s a human case, or if mosquitoes in town test positive.”
Hartline said Redding — along with telling its residents to be wary of mosquitoes and ticks — treat some wet spots in town with a larvicide.
“We’re not trying to kill them all, just to knock their numbers down,” he said.
Lisa Morrissey, New Milford’s health director, said the message still gets repeated — limit outdoor activity at dawn and dusk, remove standing water from your yard, use repellant.
But people are eager to be outside and to congregate after the 2020 shutdown — all the more reason to watch for ticks and mosquitoes.
“Last year, it was more of cabin fever,” Morrissey said. “People needed to be outside. This year, it’s more of meeting in people’s yards.”
The message is 22-yearsold. West Nile virus was once a disease found primarily in Africa and the Middle East.
The symptoms can range from very mild — like a slight case of the flu — to fatal cases involving encephalitis-like swelling in the brain. There’s no treatment or cure and and older people are much more susceptible to the virus than the young.
West Nile spread to Europe in the 1990s, then somehow jumped to the United States in 1999, where it was identified in Queens, N.Y. The Connecticut Agricultural Experiment Station was the first research station to culture and identify the virus in North America.
In the years since, it has spread across the continent making it the most common mosquito-borne illness in North America. The Centers for Disease Control and Prevention reported more than 51,000 confirmed West Nile cases and more and 2,390 deaths in the U.S. from 1999-2019.
Many cases of the illness are so mild they go unreported.
More than 160 West Nile cases have been confirmed and four deaths caused by the virus in Connecticut
Armstrong said, it’s now clear that, in Connecticut, West Nile is an urban disease, in the cities and towns along the shoreline in Fairfield and New Haven counties, then up the Connecticut River to Hartford.
That’s because the mosquito that carries West Nile in Connecticut — Culex pipiens — is an urban mosquito that like to breed in places like storm drains. So here’s the twist. The heavy rain that flooded the state in July has provided ample breeding grounds for floodwater mosquito species like Aedes vexans, Armstrong said. They’re nuisance mosquitoes that can annoy humans mightily. But they don’t carry diseases.
At the same time, the downpours tend to wash Culex pipiens mosquitoes out of storm drains. They can’t breed if they keep getting flooded out. So West Nile numbers may be lower this year.
But Armstrong said if it gets hot and sultry in August, and stays relatively dry, Culex pipiens numbers can take off. That’s happened in the past.
The state has two other mosquito-borne illnesses — Jamestown Canyon virus and Eastern equine encephalitis or EEE.
Armstrong said the Jamestown Canyon virus has been in the state for a while — when the experiment station began testing for mosquito-borne viruses in 1999, it showed up. While there have been human cases, they’re rare and mild.
“We don’t see clusters of cases like we do with West
Nile virus,” he said.
EEE is rare, but serious. Of the five people who contracted the disease in the state since 2013, four have died. The mosquitoes carrying the virus have been largely confined to the coastal towns of New London and Middlesex counties.
Armstrong said all these diseases are dependent on the mosquitoes carrying them. So think climate change. Think of the environment.
“It depends on the weather,” Armstrong said.