Health officials say some areas are at higher risk for EEE

VERMONT — A blood-sucking creature that appears at dusk is terrorizing Vermonters this summer.

No, not a vampire. Melanura Slide — A type of mosquito that spreads the rare but deadly disease eastern equine encephalitis virus.

A New Hampshire man died from the disease in August, a person in Chittenden County recently tested positive for the virus, a Sudbury man died from the disease 10 years ago, and last weekend the health department designated several towns in Addison County as at higher than average risk for mosquito-borne EEE transmission.

Recent cases in Chittenden County and an increase in mosquitoes carrying the virus led the Vermont Department of Health last week to advise residents in several areas of northwest Vermont to stay indoors between 6 p.m. and 6 a.m.

Those high-risk areas include Alburgh, Colchester, Swanston and the state's largest city, Burlington, where several events have been canceled due to EEE concerns, including Oktoberfest and Summervale at the Intervale Centre.

Other events, like Burlington's Twilight Series, are scrambling to find indoor venues, and schools in high-risk areas are postponing sports practices and back-to-school events to prevent virus spread, according to the mayor's office. Vermont Public reported.

Towns at medium risk include Vergennes, Whiting, Sudbury and Milton. Towns designated by the Ministry of Health as low risk include Cornwall, Grand Isle, Highgate and Fairfield. These risk levels are subject to change as more mosquito populations are tested.

All Vermonters should take steps to avoid mosquito bites and protect themselves from mosquito-borne diseases, even if they don't live in a high-risk area.

• Limit time spent outdoors at dawn and dusk.
• use EPA Registered Insect repellent labeled for mosquito control. Apply repellent when you are outdoors, especially at dawn and dusk.
• Wear long sleeve shirts and long pants when outdoors.
• Repair any holes in your screens and remove pooled water around your home.

When temperatures are below 60 degrees and mosquito activity is low, your risk of being bitten is lower.

State Epidemiologist Patty Kelso provided information about EEE and its prevalence in Vermont.

What is EEE?

Eastern equine encephalitis is a serious disease caused by a virus found in several animal species and spread by two types of mosquitoes, which pick up the virus by biting or sucking blood from birds and then transmit it to humans or horses, Kelso said.

EEE is not new to the region. More general According to the Centers for Disease Control and Prevention, outbreaks have begun in eastern Massachusetts and southern New Hampshire, but Vermont is still experiencing outbreaks among humans and animals, Kelso said. The last death was in 2012. Two deaths in Rutland County.

The virus wasn't detected in mosquitoes or humans in Vermont from 2016 to 2022. “The virus stays around for a few years and then disappears for a while,” Kelso said.

And in 2023, 14 mosquito nests tested positive for the virus and one horse died from the virus. “We expected something similar to happen this year,” she said.

An important distinction when discussing EEE is that not everyone who is infected with the virus will show symptoms, and not everyone who shows symptoms will develop encephalitis, the disease's most severe complication, Kelso said.

In fact, most people infected with the virus never develop symptoms. For those who do, the incubation period is usually four to 10 days, when signs like fever, chills, and joint pain start to appear. Kelso encourages anyone with these symptoms to see a doctor to rule out other causes and monitor the progression of the illness.

Only 5 percent of symptomatic patients develop encephalitis, which can include a more severe fever, stiff neck, severe headache, seizures and vomiting, Kelso said. Anyone who experiences these symptoms should seek medical attention immediately. About one-third of patients who develop encephalitis die. There is currently no cure for EEE.

Data on who is most affected by EEE is limited because sample sizes each year are so small, but evidence suggests that people under 15 or over 50 are most susceptible to the most severe complications of the disease, she said.

This year's illness

Outside of human cases, most data on EEE comes from the state Department of Agriculture, Food and Markets and the state health department testing thousands of mosquito pools each year.

Distributor Setting a trap There are traps set up around the state that attract and trap certain types of mosquitoes, including those that spread EEE and West Nile Virus. You can find out if there are any in your area here. Map of health centers.

Department officials painstakingly observe each mosquito, identify its species and place it into groups or “pools,” Kelso said, then send it off each week to a health department or CDC lab for testing.

Last month, the percentage of pools testing positive for EEE peaked at about 8%, well above the seasonal average of 1% to 2%, the health department reported. WebsiteFifteen towns in Chittenden, Franklin, Grand Isle and Addison counties have had at least one pool test positive.

The positive pool is based on the existing Disease planning Kelso urged the city to issue a shelter-in-place advisory, and while there have been no positive cases at pools in Burlington, city officials expanded the advisory to the city after recent human cases in Chittenden County.

Kelso said it would be good for Vermonters near the New Hampshire border to monitor the spread of the disease in their state. But for the most part, mosquitoes don't travel very far. “Mosquitoes don't typically travel more than about a mile from where they hatch,” Kelso said.

Prevent EEE?

When asked how dangerous it is to be outdoors in high-risk areas, Kelso stressed that of the more than 2,200 pools tested, only 66 actually tested positive for the virus, or about 3%.

Still, “that has to be an individual decision based on how concerned people are,” she said.

“If you're one of the unlucky 5% of people who get encephalitis, you're going to die a third of the time, and that's what happens,” she said. “So the message from the health department is that we strongly encourage people to avoid going out in the evening and early morning hours as much as possible.”

The health department has other recommendations for protecting yourself: Website for mosquito bite prevention measuresRecommendations include wearing longer tops and bottoms; Effective insect repellentPut mosquito nets over strollers and playpens, repair holes in window screens in your home, and remove standing water outside your home.

Kelso said even if you're wearing long clothing, mosquitoes can bite through thin fabrics, so people should consider using insect repellent.

The health department's surveillance plan calls for the use of insecticides and larvicides when necessary to control mosquito-borne diseases, and Kelso said there is no specific spraying plan in place at this time, but some areas of the state have mosquito control programs in place simply to combat mosquito nuisances.

The department plans to continue tracking the progress of mosquito testing on a weekly basis, she said, and if it were to embark on mosquito control, it would have to go through several steps before proceeding with spraying, particularly an environmental study of the area and public hearings.

“You just can't decide on a Friday, 'We need to spray crops aerialally,' and then do it on a Saturday because there's just too much that needs to be done,” she said.

Outlook for EEE

When the mosquito falls out, the EEE falls out too. The first hard frostIn the Champlain Valley, frost typically occurs in early to mid-October, and Kelso said the spread of mosquitoes and the viruses they spread begins to decline when temperatures drop below 50 degrees, even before frost kills the mosquitoes.

She said based on the virus's multi-year patterns, it appears the outbreak could continue into next summer.

“I think we'll still see symptoms of this for the next year, two, three years, but then it will subside for a while,” she said.

Unfortunately, climate change and its warming effects could mean longer mosquito seasons and the problems that come with them, Kelso said.

“In future years, if May is warm enough and mosquito activity is high, we may start trapping and testing mosquitoes in May, but right now it's more like late June or July,” she said.

For more information, HealthVermont.gov/Mosquitoes or HealthVermont.gov/EEE.