How Ticks Can Make You Sick

Also called black-legged ticks, deer ticks are common in woods and grassy areas across the eastern United States. Reddish-brown adults like the one shown here are only one-eighth of an inch long. Tiny immature ticks that are about the size of a poppy seed also bite.

Deer ticks infected with the bacteria Borrelia burgdorferi can cause Lyme disease in people, dogs, and cats. You might not even notice the tick or its bite. But if you do, remove the tick within 48 hours to limit your chances of getting Lyme disease. For some people who have Lyme disease, the first symptom is often a rash that may look like a bull’s-eye, such as the one shown above at the site of a tick bite. The rash may appear within one or two weeks — but not everyone gets or notices the rash, in part because it doesn’t itch or may not be obvious in people with darker skin tones. Other signs include flu-like symptoms such as fever, chills, headaches, aches, and swollen lymph nodes.

If you have any of these symptoms and think you may have been bitten by a tick, see your doctor for diagnosis and treatment, as Lyme disease can often be cured. If untreated, long-term infection can cause headaches, stiffness, arthritis, and an irregular heartbeat.

Black-legged ticks can transmit the bacteria that cause anaplasmosis and ehrlichiosis, per the CDC. Early signs of infection include fever, headache, muscle aches, and nausea or vomiting. Babesiosis and the Powassan virus can also result from a black-legged tick bite, notes the CDC.

Babesia, the parasite that causes babesiosis, invades red blood cells and destroys them, per the Cleveland Clinic. Babesiosis is relatively rare compared with Lyme disease, but doctors are diagnosing it more often than in years past as awareness of the disease increases and climate change drives up case counts. Per the CDC, babesiosis can be mild or even asymptomatic; when symptoms do occur they can be flu-like and include a low-grade fever, malaise, and body aches. The disease can be dangerous for immunocompromised people, the elderly, and individuals who do not have a spleen, an organ that filters blood. In some cases, black-legged ticks can infect people with babesiosis and Lyme at the same time.

Like babesiosis, Powassan virus disease can have mild symptoms or none at all, says the CDC. Symptoms include fever, headache, vomiting, or weakness. In rare cases of severe disease, the virus can infect the brain, causing encephalitis. There are no treatments, but the disease usually goes away on its own with rest and over-the-counter pain relievers.

This type of dog tick is found nearly everywhere in the United States. It likes dogs of every variety but rarely bites people. Adult brown dog ticks are about the size and color of the deer tick. The bites of brown dog ticks can be extremely dangerous to your pet: They can cause diseases like canine ehrlichiosis and bartonellosis (bacterial infections), and babesiosis. Symptoms of a tick-borne disease in your dog may include fever, depression, weight loss, and lameness, according to the American Kennel Club Canine Health Foundation. Talk to your vet about the warning signs of tick-borne infections.

Brown dog ticks can live in your house and in your dog’s kennel. If your dog has been outside in a kennel or the backyard, check often and thoroughly for ticks. Brown dog ticks hide, so make sure to look under rugs, behind draperies, under radiators, and in cracks if you think you have an infestation. The best way to get rid of them is to hire an exterminator. Remove them from a dog in the same way you would from a person: Use fine-tipped tweezers and grab the tick as close to its mouth as you can. Be sure to dispose of the tick, and wash the bite and your hands well.

Also called the wood tick, the American dog tick feeds on people, dogs, and other animals spreading infectious disease. This tick seeks out different hosts as it grows: mice and other rodents in its early stages, and people and pets in its adulthood. The full-grown ticks are reddish brown and about a half-inch long. According to the CDC, the American dog tick’s geographical range extends east of the Rocky Mountains and along parts of the Pacific coast.

The bite of this tick can lead to Rocky Mountain spotted fever, caused by the bacteria Rickettsia rickettsii, in both people and pets. These ticks also spread the bacterial disease tularemia and can cause tick paralysis (loss of muscle function, which is thought to be caused by tick saliva). If you’re bitten, you may see discoloration around the bite. Rocky Mountain spotted fever symptoms include fever, headache, body aches, swelling around the eyes or the backs of the hands, and nausea and vomiting that come on within 3 to 12 days of the bite, per the CDC. Two or three days after the fever begins, look for a spotty rash that starts on your ankles and wrists and spreads (though 10 percent of patients never develop a rash). Rocky Mountain spotted fever can be fatal if treatment is delayed, according to the CDC, but timely treatment with the antibiotic doxycycline is usually effective. Be sure to see your doctor early if you have been exposed to ticks and have any of these symptoms.

Found from west-central and east-central Texas up to the coast of Maine, lone star ticks are brown or tan, and about one-third of an inch long. Females have a distinctive white spot on their backs, while males have scattered spots or lines outlining their bodies. They can bite at any stage of their three-year life cycle.

Lone star ticks can spread ehrlichiosis and tularemia, notes the CDC. Tularemia symptoms include skin rash or ulcer, a high fever, and swollen lymph nodes. The infection can be treated with antibiotics, but if left untreated, it can be fatal.

Lone star tick bites can also cause southern tick-associated rash illness (STARI), per the CDC, which shares some Lyme disease symptoms. Signs of STARI include a bull’s-eye rash at the bite site, which often appears within a few days of the bite and can expand to three inches across. Though STARI symptoms include body aches, fever, and fatigue just as Lyme disease does, STARI doesn’t carry the long-term effects of Lyme.

Lone star ticks have also transmitted the rare Heartland virus, first identified in 2009 in two men in Missouri. As of November 2022, more than 60 cases have been reported from states in the midwestern, northeastern, and southern United States, according to the CDC. Infection causes fever, headaches, and low platelet and white blood cell counts. There is no treatment.

Allergic reactions to consuming red meat have been reported in some people bitten by lone star ticks, notes the CDC, a phenomenon known as alpha-gal syndrome (AGS). The CDC calls alpha-gal syndrome an emerging health threat, noting that between 2017 and 2022 more than 90,000 suspected cases were documented in the U.S.

While the lone star tick is commonly associated with alpha-gal syndrome, other ticks have not been ruled out.

Alpha-gal is a sugar molecule found in red meat and dairy. Someone with alpha-gal syndrome may not have an allergic reaction every time they consume red meat, and they may only be allergic to certain red meats.

Allergic reactions include hives, rash, nausea, shortness of breath, and swollen lips, tongue, eyelids, and throat. Most healthcare providers recommend that people with alpha-gal syndrome avoid red meat and, in some cases, dairy and gelatin.

The mocha-colored Rocky Mountain wood tick lives in the northwestern United States and in Canada. Young Rocky Mountain wood ticks bite small rodents; adult ticks are more likely to latch on to deer, dogs, livestock, and people.

The Rocky Mountain wood tick's bite can transmit diseases, including a virus that causes Colorado tick fever, as detailed by the American Lyme Disease Foundation, as well as Rocky Mountain spotted fever, tick paralysis, and tularemia. Colorado tick fever symptoms resemble the flu: They leave you tired, achy, and with chills, according to the CDC. The illness is usually short-lived, but there is no treatment.

The pecan-colored Gulf Coast tick lives along the coast in the southern and mid-Atlantic United States and as far inland as Oklahoma and Texas. The Gulf Coast tick can transmit the bacteria Rickettsia parkeri, according to research, which causes a spotted fever that's a milder type of Rocky Mountain spotted fever. Signs of this infection may appear anywhere from 2 to 10 days after the bite. The bite itself might look like a pimple and could be followed by a headache, an overall rash, and fever. Treatment to clear up the infection with antibiotics is usually effective.

This black and brown tick lives in the western United States and British Columbia. As a young tick, it prefers small rodents and lizards. As an adult, the western black-legged tick affects humans, pets, deer, and other large mammals. It's also a carrier of a number of diseases, including Lyme disease and anaplasmosis.

Anaplasmosis, caused by the bacteria Anaplasma phagocytophilum, can result in flu-like symptoms such as fever, chills, headache, and muscle aches, per the CDC. It may be particularly severe and even life-threatening when antibiotic treatment is delayed or if the patient is immunocompromised.

To reduce your chance of getting Lyme disease or anaplasmosis from a western black-legged tick bite, quickly remove any embedded ticks. Remember to use tweezers, not folk remedies such as matches, nail polish, or petroleum jelly. You need to get the whole tick out, and using tweezers is the best way. Save the tick so your doctor can identify it, recommends the CDC, as different ticks carry different diseases.

Additional reporting by Jean Brannum.