Where 7 Dangerous, Disease-Spreading Ticks Live in the U.S.—Mapped

If you feel the impulse to shake out your jeans and thoroughly inspect your skin when you re-enter your home, you likely live in an area with ticks. People have good reason to fear them—the little blood-sucking arachnids can transmit illnesses like Lyme Disease and more.

The United States is home to nearly 100 tick species, but not all ticks pose a threat. Some species are uninterested in humans altogether; others have never shown evidence of transmitting disease. It’s essential to understand the areas in the country where potentially dangerous ticks reside. Fortunately, the U.S. Centers For Disease Control and Prevention (CDC) has compiled an assortment of maps that show where some of the most prominent tick species live.

American Dog Tick

The American dog tick can be found anywhere east of the Rocky Mountains (and in a few select parts in the West). Adult females are the most likely to bite humans; they’re most active during the spring and summer. It would be wise to seek medical attention if you suspect you’ve been bitten, as this species has been known to transmit tularemia and Rocky Mountain spotted fever.

Blacklegged Tick

These East Coast ticks are known to carry many devastating illnesses, including Lyme disease, hard tick relapsing fever, and anaplasmosis. If that wasn’t bad enough, perhaps the most unfortunate attribute of these ticks is their resilience. Blacklegged ticks—also commonly called deer ticks—are found in spring, summer, and fall, and have even been shown to survive the winter (as long as temperatures don’t get too cold). Nymphs and adult females are most likely to bite people; because the nymphs are so small—they’re roughly the size of a poppy seed—trying to spot them crawling around your body requires a careful eye.

Western Blacklegged Tick

The western blacklegged tick is found across the Pacific coast, especially in northern areas of California. Like the blacklegged ticks found out East, this species also spreads illnesses like anaplasmosis, Lyme disease, and hard tick relapsing fever.

Lone Star Tick

Meat-lovers, beware: These aggressive ticks are famous for making some of the people they’ve bitten develop a red meat allergy. Lone Star ticks can transmit a variety of viruses, including Bourbon virus, Heartland virus, and tularemia [PDF]. Their saliva is also irritating and can cause a rash. 

Brown Dog Tick

These widespread ticks have been spotted across the U.S. and beyond. Though they are known to transmit Rocky Mountain spotted fever, they aren’t typically after humans (though they will still bite people). As their name suggests, dogs are their preferred host. To ensure your pups—and your human family members—stay safe, it’s important to be mindful of how to keep your pets tick-free.

Rocky Mountain Wood Tick

If you’re someone who lives along the coast or in the lowlands, you’re likely never going to encounter the Rocky Mountain wood tick. That’s because this particular species only inhabits areas at least 4000 feet above sea level. Look out for them when visiting the Rocky Mountain states or the southwestern part of Canada, as these ticks are known for transmitting Rocky Mountain spotted fever, tularemia, and Colorado tick fever. A neurotoxin in their saliva has also been found to cause a rare but serious (and sometimes even fatal) neurological complication called tick paralysis in both people and animals.

Gulf Coast Tick

This species is mainly found around the Gulf of Mexico and the southern Atlantic coast. These ticks are less common than others on this list, but they shouldn’t be discounted: They’re known to spread a form of spotted fever called Rickettsia parkeri rickettsiosis. The Gulf Coast tick relies on three different hosts throughout their life cycle, giving them plenty of opportunities to pass on pathogens: the nymphs and larvae prefer small mammals and birds, whereas the larger adults gravitate toward livestock and deer.

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