For the first time ever, a horse in Vermont was diagnosed with the potentially fatal eastern equine encephalitis virus.
The Agency of Agriculture received news about the Whiting horse on Friday.
On Sept. 4, EEE killed Richard Hollis Breen, 87, of Brandon and hospitalized a Salsibury man in what are the first two documented instances of humans contracting the virus in Vermont. This year, alone, the state has identified seven instances of EEE in mosquitos in the Addison and Rutland County towns of Whiting and Brandon.
To address the rise of EEE, the Department of Health (DOH) teamed up with the Agency of Agriculture and called for the aerial application of the synthetic pesticide Anvil in Whiting, Brandon and parts of Leicester, Cornwall, Shoreham and Salisbury. The night of Sept. 6 marked the first time the state has ever targeted mosquitos with pesticides from the air. More Anvil was then sprayed on Sept. 7 due to weather complications the night before.
This past Friday, state entomologist Alan Graham and Cary Giguerre, chief of the agency’s pesticide program, finished assessing the pesticide’s efficacy. According to their test results, the block over Whiting, Salisbury, Leicester, Cornwall and Shoreham reduced mosquito populations by 69 percent. And the block over Brandon cut mosquito populations by 60 percent.
These results pertain only to salient mosquito species, which includes the primary carrier of the EEE virus — the mosquito known as Culiseta melanura.
While overall mosquito populations were down, a section of Whiting held an extremely high population of Culista melanura.
“The high number of Culiseta melanura in Whiting is of concern to me,” said Graham, who has sampled more than one million mosquitos for EEE over a 15-year period. This is very unusual and something I have never seen before in the many years I have been trapping in Vermont.”
By the end of Friday, Giguere still had not received the EEE results for the mosquitos were captured after the spraying. The mosquito samples were categorized by date and region and then sent to a lab in New York on Wednesday, which crushes their bodies and tests for traces of EEE.
If the tests come back positive, the DOH would analyze the data and make a decision about whether to spray again, said DOH spokesman Robert Stirewalt.