6 tick-borne diseases you really don’t want to get

From alpha-gal syndrome to Rocky Mountain spotted fever, that tick bite could leave a terrible mark on your body.
Deer tick passing tick-borned diseases to a young person by biting back of the neck
Deer ticks don't just carry Lyme disease, but can pass on other tick-borne diseases like babesiosis too. Deposit Photos

Tick season is not only starting sooner—it’s becoming a year-round event. While April through September are usually the most active months, the pesky eight-legged parasites are biting people and animals much earlier in the year than expected. The increasing tick bites are leading to a rise in a variety of tick-borne diseases, including some that were previously uncommon.

One reason for the hike in tick-transmitted illnesses like alpha-gal, Lyme, and babesiosis is because humans are expanding towns and cities into previously forested areas. Andrew Handel, a pediatric infectious disease specialist in Stony Brook Medicine, says cutting down forests creates an edge habitat—when one habitat type meets another—which presents more opportunity for common tick hosts such as deer and mice to interact with humans. 

[Related: A guide to the tick species every American should know]

Climate change is another culprit. Changes in rain and temperature have morphed regions with low rates of tick-borne diseases into a more palatable place for the parasites to live. What’s more, warmer conditions are getting ticks to wake up earlier from their winter sleep and have more time to bite nearby mammals. “As we see more mild winters, we’re absolutely going to see more tick-borne diseases,” says Handel.

The best thing to do is to stay aware of how ticks are circulating in your area. Even if you don’t live in the Northeast, you may be at risk for other tick-borne diseases. Knowing what to watch out for in spring, summer, and even other seasons can help treat and potentially prevent future tick bites—and the diseases that follow.

Alpha-gal syndrome

A bite from the lone star tick can make you allergic to red meat for life. The unusual condition takes root when someone becomes highly sensitive to a sugar molecule called alpha-gal that’s found in most mammals. People who develop the allergy cannot eat red meat (fish and birds are safe to consume) or mammal-based products like dairy and gelatin. They may also be restricted in using certain medication such as heparin, which uses pig intestines. An allergic reaction can range from hives and nausea to more life-threatening reactions like anaphylactic shock.

Alpha-gal syndrome has been a rare but increasing tick-borne condition. In 2009, there were only 24 alpha-gal cases reported in the US. By 2021, the number was estimated to be around 34,000. And even newer surveys estimate that around 450,000 Americans might be living with the diagnosed or undiagnosed condition.

While saliva from the lone star tick seems to trigger the mammalian allergy, deer tick bites are suspected of also causing it. According to the CDC, lone star ticks have concentrated in large numbers across the country. They are found in the southeastern, eastern, and south-central US states extending from Maine to central Texas and Oklahoma. 

There is no cure for alpha-gal syndrome. Instead, people need to learn to avoid certain foods and mammal-based products. Symptoms are managed using antihistamines and corticosteroids.


Babesiosis is a parasitic infection transmitted by the bite of deer ticks (also known as black-legged ticks). These ticks are about the size of a poppy seed and found on small mammals like the white-footed mice living in the Northeast and upper Midwest. Minnesota and Wisconsin are two Midwestern states with endemic transmission of babesiosis.

Once the Babesia parasite enters the human body, it targets red blood cells. The parasites infect and destroy red blood cells by forcing their cell membrane to break open. A tremendous loss of red blood cells can, over time, cause hemolytic anemia. “It’s actually the same way that malaria works, and is why it’s called ‘the malaria of the Northeast,’” says Handel.

Babesiosis is treatable. Your doctor would prescribe a seven- to 10-day course of antibiotics if you are severely ill. Some people are at a higher risk of complications from anemia—people who are immunocompromised, those without a spleen, and newborn babies—and may need to get blood transfusions or other supportive care.

Lyme disease

Lyme disease is also spread through deer ticks. “These ticks carry and spread multiple diseases,” explains Chad Cross, a researcher at the University of Nevada, Las Vegas who studies parasites and vector-borne diseases. “If you are bitten by one, there’s always the possibility of being infected by more than one disease agent at the same time.”

While the CDC estimate shows 476,000 Lyme disease cases in the US each year, Cross states there are “at least 10 times more cases of Lyme disease than are actually reported” to the department. One reason for the discrepancy is that most cases are asymptomatic. When people do show symptoms, the fatigue and chills they exhibit can be mistaken for another condition. If left untreated, there is a risk of developing neurological problems such as facial paralysis and nerve damage to the limbs. Chronic lyme can lead to a host of persistent issues, too, many of which are still less understood. 

[Related: Biologists successfully hatched gene-edited ticks for the first time]

Most early Lyme disease cases are curable with a two- to four-week regimen of oral antibiotics such as doxycycline and amoxicillin. However, some patients may continue to experience pain, fatigue, and concentration issues six months after treatment. 


Anaplasmosis manifests as a flu-like illness in humans. The bacterium is present in deer ticks in the Northeast and Midwestern US. The Western blacklegged tick, most prevalent around the coast of California, Oregon, and Washington, can also spread the pathogen. There has been an upward trend of anaplasmosis cases from 348 cases in 2000 to 5,655 cases in 2019.

Similar to Lyme disease, people who develop anaplasmosis develop nonspecific symptoms such as fever and muscle aches. If left untreated, it may turn fatal with some developing severe bleeding problems and organ failure. Handel says doxycycline is the most effective treatment option.

Powassan virus infection

Three tick species carry the Powassan virus: the groundhog tick, the squirrel tick, and the deer tick. Of those, the deer tick is the one that often bites and infects humans. Nearly all cases of this rare virus have occurred in the Northeast and Great Lakes region.

The virus causes mild symptoms such as headache, vomiting, and fever. By the time a diagnosis is made, Handel says about half of the patients present some type of neurologic deficit. People may also continue to show neurological problems, such as chronic headaches and memory problems after recovery.

Because there are only about 20 to 30 cases a year, Handel says there’s not a lot of medical research on how to treat it. There is no cure or antivirals to treat Powassan virus. Instead, infected individuals are given fluids, over-the-counter medications, and other supportive care to ease symptoms while the immune system fights off the infection.

Diseases dog tick removed from pet's fur
A dog tick after being pulled off a pet’s fur. Deposit Photos

Rocky Mountain spotted fever

There are two main ticks responsible for spreading rocky mountain spotted fever: the Rocky Mountain wood tick and the American dog tick. Cross says the American dog tick is very common out East while the Rocky Mountain wood tick is found in the West. Despite its name, Cross says Rocky Mountain spotted fever is being found more in the East and South than in the actual Rocky Mountain region. The less-common brown dog tick has also caused several cases along the US-Mexico border. The disease is part of a larger class of illnesses that strike thousands of people in the states each year.

The most noticeable sign is a rash that looks like red splotches or pinpoint dots in the first three days after getting bit. If treated with either doxycycline or an antibacterial agent within the first one to four days, the symptoms won’t worsen. Otherwise, the disease can be fatal. After a week, Cross says that people can develop swelling in the brain, life-threatening respiratory problems, and a coma-like state. Those who recover from severe illness may be left with permanent disability, such as paralysis or amputation of limbs.

Reduce your chances of tick infections

These days, ticks are a threat across most of the US and in practically every season. Experts warn that cases will only continue to rise as ticks expand to previously uninhabitable areas. 

[Related: Climate change could introduce humans to thousands of new viruses]

Your best bet at avoiding tick-borne diseases is to keep the pests off your body. Rather than staying indoors for the rest of your life, both experts recommend spraying tick and mosquito repellant. “DEET is what we usually recommend at 20 to 30 percent,” says Handel. If you’re going to be hiking or spending a lot of time outside, learn how to handle an insecticide called permethrin. Handel advises leaving your clothes overnight in the solution to kill any insect on contact. The repellency lasts for up to 10 washes. But make sure to only use it on your clothes or gear—it’s not meant to be sprayed directly on human skin.

Remember, you can pick up ticks even if you’re not an avid hiker or camper. Ticks tend to live on tall grass, meaning they might climb on you at the park or even on your own property. Avoid rubbing up on any tall grass and keep to the middle when walking down a path. Wearing long sleeves and tucking your pants inside your socks further prevents any openings for the pests to crawl into if they latch on your clothes. 

Once you get home, immediately wash your clothes in high heat and perform a tick check for any stragglers. If you take your pet outdoors (even if it’s just the yard), you’ll want to check them daily for ticks as well. There are also topical medications that you or a vet can apply to your pet to control for any external parasites. If you or any members of your household are feeling unwell, always let your doctor know that you’ve been in wooded areas or places with high tick circulation.

“These tick-borne diseases have been around for a long time and they’re going to become more common over time,” says Handel. “But by following these steps you can keep yourself safe and still enjoying the outdoors without having to have too much anxiety about catching one of these infections.”

This post has been updated. It was originally published on March 27, 2023.