Health officials plan human testing in EEE areas
By Brent Curtis
STAFF WRITER | November 16,2012
WHITING — State Department of Health officials said Thursday that they want to test hundreds of people in Whiting and several other nearby towns to see how many residents have been infected with the deadly EEE virus.
Eastern equine encephalitis was responsible for two human deaths last summer — an 86-year-old man in Brandon and a 49-year-old man in Sudbury — as well as the death of a horse in Pittsford. The year before the virus killed about a dozen emus in Brandon.
But while untreatable and potentially life-threatening, the disease is far from 100 percent lethal, health department officials said during a hearing at the town hall Thursday night.
Tests conducted on hundreds of deer killed during hunting season in Vermont during the last two years found that as much as 10 percent of the deer herd in Vermont had developed antibodies for the virus — a sign that they had been infected by the virus but survived.
Given the minuscule number of recorded cases involving humans — health officials said only 300 have been documented during the last 50 years — the high percentage of antibodies in deer could suggest that far more of the animals were infected by the disease than ever died or developed symptoms from it.
Applying that same thinking to humans, Vermont Health Commissioner Harry Chen told a group of about 60 residents that his department is preparing to take blood samples from what could be more than a thousand people in Addison and Rutland County towns where the virus has been recorded.
“We’re going to ask people to give blood and fill out a survey to see how many people have had EEE and didn’t know it,” Chen said.
While the disease has been chronicled in the Northeast since the 19th century and is more of a concern in states such as Massachusetts than it is in Vermont, health officials said the type of test they plan to perform has only been carried out once before — in New Jersey in 1968.
The panel of health officials who spoke weren’t specific about which communities they planned to test in. But epidemiologist Erica Berl said the tests would focus on areas where health officials know the virus has been active.
“We’re looking to test about 200 to 300 people from each impacted town,” she said. “It will add understanding to how many people have been affected and what the risk is of developing symptoms.”
While health officials hope to find antibodies left by the virus, they’re not sure they’ll find any trace of EEE when they again begin testing the mosquitoes that can carry it in the spring.
“Just because we had it here this year doesn’t mean it will be back next year,” said state entomologist Alan Graham. “It fluctuates.”
Graham said scientists don’t know why the disease suddenly disappears from areas or how it moves to new locations. While the disease is found in a variety of birds, Graham and other health officials said it isn’t active in birds long enough to move effectively by migration.
Because of the disease’s penchant for disappearing, Chen said health officials don’t know yet if they will need to conduct aerial spraying to thin the mosquito populations next year.
But epidemiologist Patsy Kelso advised listeners to take precautions — such as mosquito repellent — while outdoors next year.
“We’ll be putting out the message in the community that a significant risk exists and that people need to take precautions,” she said. “If we see it in animals we’ll look at spray but it’s not an exact science. It’s not going to be as easy as saying ‘If this happens, we’ll do that.’ We’ll be making judgment calls along the way.”