Out of the 900 species of ticks in the world, only a handful are capable of transmitting diseases to humans. There are an estimated 80-90 species found within the U.S. alone. But which ones transmit diseases? In this article we look at 9 of the most common types of ticks in the United States that everyone should watch out for and what diseases they spread.
9 types of ticks in the United States
Ticks are very small arachnids that survive on a diet of just blood and can go for almost 500 days with no food. Once fully engorged with blood, ticks swell to several times their normal size. At this point they will find a mate and die soon after.
1. Blacklegged tick
- Scientific name: Ixodes scapularis
- Length: 3 mm (6 or 7 when engorged)
- Distribution: Eastern half of U.S.
- Transmits: Lyme disease, anaplasmosis, B. miyamotoi disease, ehrlichiosis, babesiosis, Powassan virus
The blacklegged tick, commonly referred to as the deer tick, is widespread throughout the Eastern half of the contiguous United States. They’re found in the eastern parts of Texas, Oklahoma, and Nebraska north as well as all states east to the coast.
They live in wooded areas and can usually be found on a branch or plant of some type, waiting jump onto an animal. Blacklegged ticks commonly carry the bacteria Borrelia burgdorferi and Borrelia mayonii, which causes lyme disease. Nymphs and adult females are most likely to bite humans in spring, summer, and fall.
2. Western blacklegged tick
- Scientific name: Ixodes pacificus
- Length: 3 mm (6 or 7 when engorged)
- Distribution: Mainly California, Pacific Northwest, and some Southwestern states
- Transmits: Anaplasmosis, Lyme disease
In the U.S. this species is found in California and the Pacific Northwest. They look very similar in appearance to a common deer tick, or blacklegged tick. There are slight variations in color and body features between the two ticks if you know what you’re looking for.
3. American dog tick
- Scientific name: Dermacentor variabilis
- Length: 5 mm (10 to 15 when engorged)
- Distribution: Most of California, eastern half of the U.S.
- Transmits: Rocky Mountain spotted fever, Tularemia, Ehrlichia, Anaplasma, tick paralysis
The American Dog Tick gets its name due to its preference for feeding on domesticated dogs. However, it can also attach and feed on people as well.
The ticks are brown with white or gray markings. They have an oval-shaped body and are 5mm unengorged and 15mm engorged. The ticks are most active from May to November.
4. Brown dog tick
- Scientific name: Rhipicephalus sanguineus
- Length: 3 mm (up to 13 when engorged)
- Distribution: Throughout United States, all 50 states
- Transmits: Rocky Mountain spotted fever
Brown dog ticks get their name from their brownish color and their preference for dogs. They can attach to humans but rarely do so. These ticks are about 3mm in size when un-engorged and 12mm when engorged.
They take on a gray-blue color when engorged. Brown dog ticks are one of the few species of ticks that can survive inside. That is why they can be dangerous when brought into a breeding facility or a home with multiple pets.
5. Gulf Coast tick
- Scientific name: Amblyomma maculatum
- Length: 6 mm (12+ when engorged)
- Distribution: Gulf coast states, a few inland southern states
- Transmits: rickettsiosis (a type of spotted fever)
The Gulf Coast tick is common throughout southern states in the U.S. that border the Atlantic or Gulf of Mexico. They can be found as far north as Colorado, Tennessee, or even New Jersey.
These ticks feed primarily on birds and mammals but will commonly bite humans when given the chance. They’re known for spreading a type of spotted fever, Rickettsia parkeri rickettsiosis, among other pathogens.
6. Pacific Coast tick
- Scientific name: Dermacentor occidentalis
- Length: 3 mm (over .5 inch when engorged)
- Distribution: From Oregon to Baja California
- Transmits: 364D rickettsiosis (discovered in California)
Pacific coast ticks aren’t widespread and are found along the west coast of the United States in California, Oregon, and Washington. Ticks infected with R. philipii are known for spreading the Pacific Coast Spotted Fever.
7. Rocky Mountain wood tick
- Scientific name: Dermacentor andersoni
- Length: 3 mm (up to 15 when engorged)
- Distribution: Colorado, Wyoming, Utah, Nevada, Montana, Idaho, Washington, Oregon, New Mexico, Arizona
- Transmits: Rocky Mountain spotted fever, Colorado tick fever, tularemia
The Rocky Mountain wood tick is found in the Rocky Mountain regions of the northwestern United States. They are one of the main spreaders of Rocky Mountain spotted fever, Colorado tick fever, and tularemia.
They’re common in open grasslands or woodlands where they wait on a blade of grass or branch for an animal to pass by.
8. Lone star tick
- Scientific name: Amblyomma americanum
- Length: 3 mm (13 when engorged)
- Distribution: Widespread in eastern U.S. south of the Great Lakes
- Transmits: ehrlichiosis, Heartland virus, tularemia, STARI
The Lonestar tick gets its name from its unique coloring. Females have a brown scutum with a large white dot in the middle. The ticks are most active from late spring to early fall.
The ticks are known to be extremely aggressive, attaching to anything that comes in their path. They are able to survive without a host for up to a full year.
9. Groundhog tick
- Scientific name: Ixodes cookei
- Length: 3 mm
- Distribution: Eastern half of the U.S.
- Transmits: Powassan virus disease
While the woodchuck tick prefers wild animals, it will attach to domesticated animals and occasionally humans. When it is fully engorged, it is approximately the size of a sesame seed.
Woodchuck ticks, otherwise known as groundhog ticks, look extremely similar to deer ticks. A microscopic investigation may need to be completed in order to determine the species. Deer ticks carry Lyme disease, while woodchuck ticks do not.
How to Avoid Ticks
Now that you are aware of the most common ticks living in the United States, it’s vital to understand how to avoid getting bit. Here are some common tips to follow to avoid getting bitten by ticks:
- Wear long pants and tuck them into your socks.
- Wear bug spray with less than 30% DEET.
- Pre-treat clothing with a chemical repellant like permethrin
- Stay towards the center of trails
- Avoid tick-infested areas (i.e., high grass, off-trail trekking, etc.)
In addition to following the common practices above, you should also check yourself and your animals for ticks anytime you go to a place that may have been infested by ticks. Make sure to check the following areas on your own body:
- Pubic area
- Back of knees
Additionally, you should check your animals’ armpits and behind their ears very carefully. Finally, you should shower within two hours of coming indoors as this will help wash away any unattached ticks.
What Should I Do If I’m Bitten by a Tick?
If you find that you have been bitten by a tick, you should follow the following steps to remove it as quickly as possible:
- Use tweezers to get as close to your skin as possible
- Pull upward. Do not twist or jerk.
- Once the tick is removed, clean the area with rubbing alcohol or soap and water.
- Flush the tick down the toilet, or if you’d like to get it identified, pour rubbing alcohol on it and place it in a sealed bag.
It is essential to remove a tick as soon as it has been identified. This will help prevent the spread of any diseases. You will want to monitor yourself for up to 30 days for the following symptoms:
- Joint pain
- Muscle pain
If you experience any of the above symptoms, go see a doctor as soon as possible and make sure to mention the tick bite.
The Dangers Tick Pose
While tick bites can be uncomfortable and a little unnerving, the bite itself is not the main concern. Ticks are known vectors of several diseases that can be harmful to both humans and animals alike.
One of the most common diseases passed from tick to human is Lyme disease. If left untreated, Lyme disease can cause joint pain and even negatively impact your central nervous system. Regardless of where you are in the United States, it’s essential to be on the lookout for ticks and always see a doctor if experiencing symptoms after a tick bite.