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%).
