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.
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.
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.
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%).
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
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
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.
Name: Squirrel tick (Ixodes marxi)
Distribution: throughout Vermont
Habitat: the nests of their hosts
Hosts: mostly squirrels, but also other medium-sized mammals; rarely bite humans
Transmits: Powassan virus (extremely rare in Vermont)
Active: generally, in warmer months
Name: Woodchuck tick (Ixodes cookei)
Distribution: throughout Vermont
Habitat: the burrow of their host animal; rarely on vegetation
Hosts: woodchucks, foxes, skunks, weasels, porcupines, small mammals, some bird species, raccoons, cats, dogs; rarely bite humans
Transmits: Powassan virus (extremely rare in Vermont)
Active: generally, in the summer months
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:
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.
Share information about where and what kind of ticks you find to the Vermont Tick Tracker.
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.
Several trends were revealed in the most recent 2021 Tick Pathogen Surveillance Report:
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.
