Mosquitoes Test Positive for West Nile and Jamestown Canyon Viruses

For Immediate Release: July 25, 2025

Media Contact:
Kyle Casteel - Media Lead

Communication Office │ Department of Health

Media Contact:

Scott Waterman | Vermont Agency of Agriculture, Food & Markets

Mosquitoes Test Positive for West Nile and Jamestown Canyon Viruses
Health officials urge Vermonters take steps to prevent mosquito bites

WATERBURY, VT — The first positive results of mosquito testing this year have detected two viruses in the state: West Nile virus in St. Albans and Jamestown Canyon virus in Rutland. This is the first year Vermont is testing for Jamestown Canyon virus, which can cause illness in people similar to other mosquito-borne viruses.

There have been no human or animal cases of mosquito-borne illnesses reported so far this season. Health officials are encouraging people in Vermont to protect themselves from mosquito bites and the potentially dangerous diseases they can spread.

Mosquitoes are tested for three viruses that can be spread through the bite of an infected mosquito: West Nile virus, Eastern equine encephalitis (EEE) virus, and this year, Jamestown Canyon virus.

Most people who are infected with these viruses do not feel sick, but they can lead to serious illness, such as inflammation of the brain, called encephalitis. Symptoms can include fever, headache, body aches, joint pains, vomiting, diarrhea, or a rash. Anyone who has symptoms should contact their health care provider.

The best way to protect yourself and your family is to prevent mosquito bites:

Wear long-sleeved shirts and pants outdoors.
Limit your time outside at dawn and dusk when mosquitoes are more likely to bite.
Use insect repellent labeled as effective against mosquitoes. The EPA has a tool to help find the right repellent for you. These products can also protect you from tick bites.
Get rid of standing water, including flowerpots, buckets, barrels, wading pools and other toys and containers.
Cover strollers and outdoor playpens with mosquito netting.
Fix holes in screens and make sure they are tightly attached to doors and windows.

Since 2002, there have been 17 confirmed human cases of West Nile in Vermont. EEE, or “Triple E” – which is more deadly – caused illnesses in two people in Vermont last year, one of whom died. Last year, significantly higher numbers of mosquitoes tested positive for EEE virus in more areas of the state than in any previous years. Vermont has not had any reported cases of infection with Jamestown Canyon to date.

As part of the state’s annual surveillance efforts, the Agency of Agriculture, Food and Markets collects mosquitoes throughout Vermont, which are then tested at the State Public Health Laboratory each week. As of July 24, more than 46,000 mosquitoes have been collected.

Horse owners should consult their veterinarians and make sure their animals are up to date on vaccinations for West Nile, EEE, and other diseases spread by infected insects or ticks. Horses cannot spread these viruses to humans or other horses, but the infections can cause neurologic disease and death in unvaccinated animals.

Learn more about mosquitoes, the diseases they spread, and how to prevent bites – Visit HealthVermont.gov/Mosquito.

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