Mosquito-Borne Diseases In Connecticut: Town-By-Town

CONNECTICUT ? It's late July, and that means it is peak mosquito season in Connecticut.

Nobody has a better understanding of all that implies than the entomologists at the Connecticut Agricultural Experiment Station, who maintain a network of mosquito monitoring stations throughout the state. This is the state's "early warning system" for the bug-borne diseases.

CAES field teams hit each of the 100 locations on a weekly basis, set the traps out overnight, then bring the insects back to their lab in New Haven. There they are identified to the species level and tested for viral infection.

The routine dates back to 1997 and was established originally to monitor for eastern equine encephalitis. The state Department of Energy and Environmental Protection expanded the program later to look for West Nile virus, and other mosquito-borne diseases.

CAES oversees the monitoring program, but the agency gets some assistance from the University of Connecticut. Viral cases found in wildlife are passed on to diagnostic labs at UCONN's Agriculture and Pathobiology Departments. If there's an outbreak among humans, the state Department of Public Health gets involved.

They won't have long to wait. There are reports of West Nile Virus in New York, New Jersey and Pennsylvania.

"So I think we're next in line, I expect to see it in any day now," Philip Armstrong, director of the CAES mosquito surveillance program, told Patch. "This hot, humid weather really drives the transmission of West Nile Virus ...we'll start to see it in mosquitoes in July, and then human cases follow."

West Nile virus has been detected in Connecticut every year since it was introduced into North America in 1999. Only about 1 in 5 people who are infected develop a fever and other symptoms, which can include headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. About 1 out of 150 infected people develop a serious or possibly fatal illness.

EEE emerges still later in August, if it emerges in the human population at all. Unlike West Nile virus cases, which appear reliably each year, EEE is rare. The last time Connecticut saw a big outbreak ? including three fatalities ? was 2019, Armstrong said.

Most EEE cases pop up in eastern or Gulf Coast states, and are a cause for alarm when they do. Approximately 30 percent of people with EEE die, and many survivors have ongoing neurologic problems, according to the Centers for Disease Control and Prevention. Symptoms include fever, headache, vomiting, diarrhea, seizures, behavioral changes, drowsiness, and coma.

The lesser-known player, and the only one to show up in the CAES data this early in the season, is Jamestown Canyon virus. It's a neuro-invasive disease found throughout much of the United States, but most cases are reported from the upper Midwest, according to the CDC. Common symptoms include fever, headache, and fatigue. Jamestown Canyon virus can lead to more severe disease, including encephalitis.

Besides the mosquitoes on which they ride into town, EEE, WNV and JCV share one other commonality: There are currently no vaccines to prevent, or medications to treat, the diseases in people.

What scientists do know, is how to reduce the risk of infection. CAES officials are advising residents to take the following steps to reduce the risk of being bitten by mosquitoes:

• Minimize time spent outdoors between dusk and dawn when mosquitoes are most active.
• Be sure door and window screens are tight-fitting and in good repair.
• Wear shoes, socks, long pants, and a long-sleeved shirt when outdoors for long periods of time, or when mosquitoes are more active. Clothing should be light colored and made of tightly woven materials that keep mosquitoes away from the skin.
• Use mosquito netting when sleeping outdoors or in an unscreened structure and to protect infants when outdoors.
• Consider the use of an EPA-approved mosquito repellent and apply according to directions when it is necessary to be outdoors.