Tick Activity in Vermont | Vermont Department of Health

Tick-related emergency room visits are most common in the spring and fall. This graph shows the weekly percentage of emergency department visits for tick-related issues, with the purple line showing the average percentage of visits (based on 2017-2022 data), the green line showing the highest percentage of visits recorded at that time, and the blue bars indicating the current year.

Tick Species Found in Vermont

Every year, ticks are collected from several locations around Vermont and identified by their species, life stage, and sex. Blacklegged ticks are responsible for 99% of all tick bite illnesses reported to the Vermont Department of Health.

Blacklegged Tick

Name: Blacklegged tick (Ixodes scapularis)

Distribution: throughout Vermont

Habitat: wooded areas and fields with tall grass and brush

Hosts: white-footed mouse, deer mouse, chipmunks, shrews, white-tailed deer

Transmits: the pathogens that cause Lyme disease, anaplasmosis, babesiosis, Powassan virus disease, and Borrelia miyamotoi disease

Active: In Vermont, blacklegged tick peak activity typically occurs in May and June when nymphal ticks are looking for a host. Tick activity increases again in October and November when adult female ticks are looking for another host before winter. Although blacklegged tick activity typically follows this pattern, these ticks may be encountered any time of year when temperatures are above freezing.

How common are disease-carrying blacklegged ticks in Vermont?

In 2018, the Vermont Department of Health initiated a project in collaboration with the Vermont Agency of Agriculture to understand the prevalence and geographic distribution of disease-carrying blacklegged ticks. Over 1,500 ticks were collected from 48 sites around the state in 2020; human-feeding nymphs and adult female ("host seeking") ticks were tested for four pathogens.

PAthogen	Percentage of ticks that tested positive
Borrelia burgdorferi	59%
Anaplasma phagocytophilum	11%
Babesia microti	6%
Borrelia miyamotoi	1%

Blacklegged ticks can carry more than one pathogen at the same time. The most common combinations were the pathogens that cause Lyme disease and anaplasmosis (8%) and the pathogens that cause Lyme disease and babesiosis (5%).

American Dog Tick

Name: American dog tick (Dermacentor variabilis)

Distribution: throughout Vermont

Habitat: mostly in grassy fields and other areas with little tree cover

Hosts: small rodents and medium-sized wild mammals, domestic cats, dogs and humans

Transmits: the bacteria that causes tularemia and Rocky Mountain spotted fever (human cases in Vermont are extremely rare)

Active: April through September

Brown dog tick

Name: Brown dog tick (Rhipicephalus sanguineus)

Distribution: throughout Vermont

Habitat: wherever humans and dogs live including indoors, unlike other tick species

Hosts: mostly dogs

Transmits: the bacteria that causes Rocky Mountain spotted fever in the Southwestern United States (no evidence of transmission in Vermont)

Active: throughout the year

Lone Star Tick

Name: Lone star tick (Ambylomma americanum)

Distribution: this tick is not considered established, or able to complete its entire life cycle, in Vermont

The Health Department works with other state agencies to search for the lone star tick in Vermont and support people with information to protect themselves.

Habitat: woodlands with plenty of undergrowth and areas with tall, shaded grass

Hosts: squirrels, raccoons, deer, cattle, some bird species, cats, dogs and humans

Transmits: the pathogens that cause ehrlichiosis and tularemia (human cases in Vermont are extremely rare). Alpha-gal syndrome (AGS).

Active: April through September. While most ticks wait in grass or brush to grab on to people or animals who pass by (questing), lone star ticks also actively track down a host by following the trail of air the host breathes out.

Squirrel Tick

Woodchuck Tick

Blacklegged Tick Life Cycle

The blacklegged tick goes through four life stages: egg, larva, nymph, adult. This life cycle lasts about two years. At each stage (with the exception of egg), the tick must attach to a new host for food. Once attached, it will suck the blood of its host slowly, for several days. When the tick is full, it will fall off on its own. This may take as little as 3-6 days, but up to two weeks. It may leave behind a tiny red bump.

This means that humans and other animals are most at risk for blacklegged tick bites:

During late spring (May and June), when larvae become nymphs and need a new food source.
In the fall (October and November), when nymphs become adults and need a new host.

If a host animal has a tick bite illness already, such as Lyme disease, the blacklegged tick feeding off of it will then become infected for life. When that same tick later bites on a human, it will spread the disease.

Found a Tick?

Share information about where and what kind of ticks you find to the Vermont Tick Tracker.

Report a tick

Tick Bite Illnesses Impacting Vermonters

Lyme disease is the most common tick bite illness in Vermont, followed by anaplasmosis and then babesiosis. Cases of anaplasmosis and babesiosis have increased significantly over the last ten years.

Cases of hard tick relapsing fever and Powassan virus are less common today; there have been fewer than 65 cases of hard tick relapsing fever reported to the Health Department since its emergence in 2016, and two cases of Powassan virus in Vermont residents since 1999.

Explore tick bite illness data

Key Trends

Several trends were revealed in the most recent 2021 Tick Pathogen Surveillance Report:

Of the 4,796 ticks that were collected in 2021, 92% were blacklegged ticks
Over half of these blacklegged ticks were infected with a pathogen that causes tick bite illness in humans
Borrelia burgdorferi (bacterium that causes Lyme disease) was the most common pathogen infecting blacklegged ticks

Addison and Orange Counties were found to have some of the highest densities of nymph ticks. This is significant because ticks in the nymph life stage are tiny (less than 2 mm) and difficult to see, and they may be able to feed on human hosts longer, increasing the likelihood of tick bite illness.

Additional Reading