Why rates of the tick-borne disease Babesiosis are rising

Researchers at Penn State analyzed a large database of clinical patient data on more than 250 million people and found that the number of babesiosis infections increased an average of 9 percent per year between 2015 and 2022.

Here you can read more about the disease and how to avoid it.

What is babesiosis?

Babesiosis, also called “American malaria,” is a disease caused by the Babesia parasite and spread primarily through tick bites, most commonly via black-legged or deer ticks, according to the Centers for Disease Control and Prevention (CDC). The parasite infects the host’s red blood cells.

Babesiosis is sometimes found alongside other diseases; The study found that 4 in 10 people with the disease were co-infected with another tick-borne disease. But interestingly, having both babesiosis and Lyme disease is not associated with a higher mortality risk, the researchers say. In fact, the opposite is true: the mortality risk is higher for people who have only babesiosis.

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Babesiosis is on the rise

Babesiosis is not as common as Lyme, but it is increasing. “We found a 9 percent annual increase in babesiosis cases in the US, although this could be even higher,” Paddy Ssentongo, MD, PhD, a physician-scientist and lead author of the study, tells Well+Good.

He thinks several factors could explain this. The first is climate change, or a warmer climate, which affects the population and distribution of ticks and their hosts, leading to greater geographic distribution. (This may also explain why cases spike during the summer.)

Second: human behavior. “The encroachment of the forested areas where the reservoir hosts lie for Babesia infection has increased the interface between the reservoir hosts and humans,” he says. (In other words, people are spreading more and more into tick territory, increasing the number of bites.)

Third, there is simply more awareness around Babesia and clinical manifestations so that more healthcare providers can make this accurate diagnosis, says Dr. Ssentongo.

The symptoms of babesiosis

According to the Cleveland Clinic, signs of babesiosis don’t begin until one to four weeks after exposure, and about a quarter of infected people have no symptoms at all. If symptoms are present, they include high fever, fatigue, chills, sweating, headache, muscle or joint pain, loss of appetite, and coughing.

Because many other diseases share these symptoms, it is important to make sure you get the right tests done by the doctor. (Babesiosis is diagnosed through a blood test.)

It is especially urgent to see a doctor if you show symptoms of severe babesiosis. These include yellowish skin or eyes, pale skin, dark urine, shortness of breath, nausea and vomiting, abdominal pain, neck stiffness, and sudden mood swings or extreme emotional reactions.

How it is treated

Babesiosis can be treated, according to the CDC, although most asymptomatic people do not need treatment.

For most people who do have symptoms, a seven- to 10-day course of two prescription medications is the best choice. Usually the medications are atovaquone (an anti-parasite) and azithromycin (a type of antibiotic). People with weakened immune systems may need a longer course of treatment.

Dr. Ssentongo says doxycycline, another type of antibiotic, can also be added to the treatment plan.

But your best guess? Prevention.

Should we worry about babesiosis?

People with certain health risks or careers may want to be extra cautious about this disease. Dr. Ssentongo says anyone can become infected, but people without a spleen, people with weakened immune systems (such as people with cancer or HIV) and people over 50 are at increased risk of complications.

As far as careers go, it’s really about how often you spend time outside. Preventing tick bites is especially important for people who spend long hours outdoors. Dr. Ssentongo recommends using tick repellents, wearing long pants and avoiding long grass. If you find a tick attached to your body, he says, send it in for testing for tick-borne diseases and be examined by a health care provider.

It is also important to note that babesiosis is endemic in certain US states: Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, Wisconsin, Maine, New Hampshire, and Vermont. According to Dr. Ssentongo has also spread to Pennsylvania.

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

“This epidemiological shift in infections should raise awareness of the need to implement prevention strategies for the prevention of tick bites,” says Dr. Ssentongo, “but also to create increased vigilance among healthcare providers to diagnose and treat Babesia cases early.”