Ticks are a common concern for people and pets across the United States, but not all ticks pose the same risks. With hundreds of species in North America, many feed exclusively on wildlife or thrive in very specific habitats, meaning most are rarely encountered by humans. However, some species are widespread and commonly come into contact with people and pets in everyday outdoor spaces.
The ticks that most commonly affect humans include deer ticks, American dog ticks, lone star ticks, brown dog ticks, and Western blacklegged ticks. While these ticks share similar life cycles and environmental preferences, each carries its own set of potential pathogens and is found in distinct regions of the country.
Deer Tick (Blacklegged Tick) – Ixodes scapularis
Deer ticks can be found in every U.S. state except Hawaii, but they’re most common along the eastern U.S. coast from Florida to Maine and in the Great Lakes region.
Nymphs and adult females pose the greatest risk to humans, with nymphs causing more Lyme cases due to their small size.
Diseases carried:
- Lyme disease
- babesiosis
- bartonellosis
- anaplasmosis
- B. miyamotoi
Western Blacklegged Tick (Ixodes pacificus)
Western blacklegged ticks are found along the U.S. west coast, most commonly in coastal California, Oregon, and Washington.
Juvenile western blacklegged ticks feed on birds, small rodents, and even lizards, while adults prefer deer and other large mammals such as humans.
Diseases carried:
- Lyme disease
- anaplasmosis
Lone Star Tick (Amblyomma americanum)
Once mostly confined to the southern U.S., lone star ticks have been spreading north and now inhabit much of the eastern United States—from Texas and Iowa to the Atlantic coast—even reaching as far north as Maine. They remain most common in southern regions.
Lone star ticks are considered one of the most aggressive tick species
Diseases carried:
- Ehrlichiosis
- Tularemia
- Southern Tick-Associated Rash Illness (STARI, caused by Borrelia lonstari)
- Alpha-Gal Syndrome (meat allergy)
Brown Dog Tick (Rhipicephalus sanguineus)
Brown dog ticks are found throughout the entire United States, though they are most common in warmer southern regions.
These ticks pose a significant disease risk to dogs, carrying bacteria that can cause illnesses such as canine ehrlichiosis and babesiosis.
Diseases carried:
- Rocky Mountain spotted fever
- Ehrlichiosis (possible)
- Canine ehrlichiosis (Ehrlichia canis)
- Canine babesiosis (Babesia canis)
American Dog Tick (Dermacentor variabilis)
American dog ticks are found throughout areas east of the Rocky Mountains and along a small section of the west coast. They typically inhabit woods, brush, and tall grasses.
Larvae and nymphs feed on small mammals such as rodents, while adults prefer larger mammals.
Diseases carried:
- Rocky Mountain spotted fever (RMSF)
- Tularemia
Protect Yourself by Knowing the Risks
Remaining informed about ticks and the diseases they carry is key to keeping yourself, your family, and your pets safe during tick season. Know which ticks are active in your region and understand the potential risks. Staying vigilant and prepared is the best way to enjoy the outdoors safely.
Worried About a Recent Tick Bite?
If you’ve removed a tick and want peace of mind, TickCheck offers fast and reliable tick testing services. Simply send the tick to our lab, and we’ll identify the species and test it for Lyme disease and other common pathogens. Knowing whether a tick was carrying disease can help you and your doctor make informed decisions about next steps.