Why the tick-borne disease babesiosis is on the rise

Penn State researchers analyzed a large clinical patient database of more than 250 million people and found that babesiosis infection rates increased by an average of 9% per year from 2015 to 2022.

Here’s more information about the disease and how to avoid it.

What is babesiosis?

Babesiosis, sometimes called “American malaria,” is a disease caused by the parasite Babesia and is primarily spread through tick bites—usually Transmitted by black-legged or deer ticks. The parasite infects the host’s red blood cells.

Babesiosis is sometimes found along with other diseases. Research shows that four out of 10 people with the disease are also infected with another tick-borne disease. But interestingly, having both babesiosis and Lyme disease was not associated with a higher risk of death, the researchers said. In fact, the opposite is true: People with babesiosis alone have a higher risk of death.

Related stories

Babesiosis on the rise

Babesiosis is not as common as Lyme disease, but its incidence is increasing. “We found that babesiosis cases in the United States are increasing by 9% per year, although it may be higher,” Paddy Ssentongo, MD, PhD, lead author of the study, told Well+Good.

He believes several factors may explain this. The first is climate change, or warming, which affects the abundance and distribution of ticks and their hosts, leading to greater geographic distribution. (This may also explain why cases peak in the summer.)

Second, human behavior. “Encroachment of Babesia-infected hosts into wooded/forested areas increases contact between hosts and humans,” he said. (In other words, people are increasingly entering tick territory, which increases the number of tick bites.)

Third, there is more awareness about babesiosis and its clinical manifestations, so more health care providers are able to give accurate diagnoses, Dr. Ssentongo said.

Symptoms of babesiosis

Symptoms of babesiosis don’t appear until one to four weeks after exposure, and about a quarter of people infected show no symptoms at all, according to the Cleveland Clinic. When symptoms occur, they include high fever, tiredness, chills, sweating, headache, muscle or joint pain, loss of appetite, and cough.

Since many other diseases have these symptoms, it’s important to make sure you get the right tests at your doctor’s office. (Babesiosis is diagnosed with a blood test.)

Urgent medical attention is especially needed if you have symptoms of severe babesiosis. These symptoms include yellowing of the skin or eyes, pale skin, dark urine, shortness of breath, nausea and vomiting, abdominal pain, stiff neck, and sudden mood changes or extreme emotional reactions.

how to treat

According to the CDC, babesiosis is treatable, although most people who are asymptomatic do not need treatment.

For most people who do have symptoms, a 7- to 10-day course of two prescription drugs is preferred. Typically, the drugs are atovaquone (an antiparasitic drug) and azithromycin (an antibiotic). Immunocompromised people may need a longer course of treatment.

Another antibiotic, doxycycline, may also be added to the treatment plan, Dr. Ssentongo said.

But what’s your best option? prevention.

Should we worry about babesiosis?

People with certain health risks or occupations may need to be extra cautious about this disease. Anyone can become infected, but people without a spleen, people with weakened immune systems (such as those with cancer or HIV) and people over 50 are at higher risk of complications, Dr. Ssentongo said.

As far as careers go, it really depends on how often you go out. Preventing tick bites is especially important for people who spend a lot of time outdoors. Dr. Ssentongo recommends using tick repellent, wearing long pants and avoiding long grass. If you find a tick on your body, send it in for testing for tick-borne diseases and have you evaluated by a health care provider, he said.

Also note that babesiosis is endemic to certain states in the United States: Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, Wisconsin, Myanmar, Indiana, New Hampshire and Vermont. Dr. Ssentongo said the spread has also expanded to Pennsylvania.

If you live in one of these areas, you may want to pay extra attention to any symptoms that arise.

“The epidemiological shift in infection should increase awareness of preventive strategies to prevent tick bites, while also increasing the vigilance of health care providers to diagnose and treat Babesia cases as early as possible,” said Dr. Ssentongo.