Influx Of Virus-Carrying Mosquitoes Expected In Connecticut

CONNECTICUT — The mosquito species that carries Eastern equine encephalitis has been spotted in Massachusetts and Rhode Island, and a top Connecticut entomologist says it's a matter of "when," not "if" the pest shows up here.

Virologist and medical entomologist Philip Armstrong runs the statewide mosquito trapping and testing program. His team at the Connecticut Agricultural Experiment Station has already increased the number of trap sites this year from 92 to 108. The 16 additional location are all in the eastern part of the state, which Armstrong said has been a "problem" area for the EEE virus.

So far? So good.

"Overall, mosquito trap collections are below average and the abundance of Culiseta melanura mosquitoes — the main carrier of EEE virus — is about average but this could change depending on the weather conditions during the rest of the summer," Armstrong said.

It's still early. Historically EEE doesn't emerge until early to mid-August in the Nutmeg State. When the infected bugs do arrive, hopefully it won't be as big a population as last season's swarm. Armstrong called the 2019 mosquito season a "perfect storm of events that led to very high levels of virus activity."

"Last year was a very unusual year," Armstrong said. "We had one of the biggest outbreaks of EEE virus nationally in some 50 years." Connecticut, Rhode Island and Massachusetts were particularly hard-hit.

The primary carriers of the EEE virus are birds, according to the entomologist. But birds don't typically swarm and bite you in your backyard. The mosquitoes who pick up the virus from the birds do, however, and so it's upon these creatures the virologists focus their efforts.

"We think that since there was a long period of quiescence, there wasn't much immunity in the bird population, so the birds were susceptible to the virus, and that created the conditions that allowed for high virus activity last year."

"We don't see EEE every year in CT. It fluctuates quite a bit from year to year," Armstrong said. The first human case of EEE reported in Connecticut occurred in the fall of 2013.

Mosquitoes are very sensitive to weather Armstrong explained. When the water table is high in the freshwater swamps where the bugs live and breed, mosquitoes — and the EEE carrier in particular — start breeding in overdrive. We had a lot of rainfall during the previous fall and winter leading up to mosquito season last year, which made for ideal conditions for mosquitoes in those swamp habitats.

"When the virus gets seeded into our area, it will persist for a few years before it dies out," Armstrong said. "We know that the virus has already reemerged in Massachusetts and New Jersey, and it's only a matter of time before we see it in Connecticut."

The incubation period for EEE (the time from infected mosquito bite to onset of illness) ranges from 4 to 10 days, according to the Centers for Disease Control and Prevention. The infection can result in a systemic febrile illness or neurologic disease, including meningitis or encephalitis. Some people who become infected with EEE may be asymptomatic.

The illness lasts one to weeks, and most people recover completely when there is no central nervous system involvement. Systemic infection is characterized by fever, chills, malaise, arthralgia, and myalgia. Signs and symptoms of neurologic disease include fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and coma. In infants, neurologic disease often occurs soon after onset; in older children and adults, encephalitis may occur after several days of systemic illness.

Approximately a third of all people with encephalitis due to EEE infection die. Death usually occurs two to 10 days after onset of symptoms but can occur much later.

Armstrong is hoping that when the virus does return, it'll be later in the summer, when mosquitoes are already on their way out. "We've already detected West Nile Virus, we expect EEE is on the way." So now is the time to take protective measures.

There's no special trick to that: It all comes down to reducing your exposure to mosquito bites. That means wearing long pants and long sleeve shirts whenever possible when working or sitting in your yard. Armstrong also recommends using an insect repellent that has been approved by the Environmental Protection Association, and being inside when the bugs are most active.

"The mosquitoes that transmit EEE tend to be most active at dusk, dawn and into the evening hours. They're not 'day biting' mosquitoes," Armstrong said.

Homeowners should also make a point of eliminating standing pools of water around their property, such as clogged drain gutters and even bird baths. "That water needs to be thrown out at least once a week to eliminate mosquito reproduction," Armstrong said.

See also: CT Lifts Some Coronavirus Restraints It Placed On Businesses

• Long Delay Pushes CT's Coronavirus Case Count Up
• New Historic Police Reform Bill Advances: 5 Fast Facts