Tick-borne disease is on the rise, new study says

You’ve heard of Lyme disease—now, infectious disease experts are warning about another serious tick-borne illness that’s on the rise: babesiosis.

“If you live in areas where babesiosis is endemic, primarily in the northeastern and midwestern states, take precautions, especially during the summer months,” said study lead author Paddy Ssentongo, a Penn State Health Milton S. Hershey fellow in infectious disease. Medical. Center.

Ssentongo’s team found that rates of babesiosis, a potentially life-threatening disease sometimes referred to as “American malaria,” increased an average of 9% per year in the U.S. between 2015 and 2022. Plus, four in 10 patients were found to be co- infected with Lyme disease or any other tick-borne disease.

Ssentongo blames the increase in babesiosis on changes in the length of seasons, temperature, humidity and rainfall that affect the tick population.

His findings were published Tuesday in the journal Open Forum Infectious Diseases.

Here’s everything you need to know about babesiosis.

What is babesiosis?

Babesiosis is a disease caused by Babesia parasite. It is mainly transmitted through the bite of a black-legged tick, also known as the deer tick. As with malaria, the parasite infects red blood cells.

Transmission can also occur through blood transfusions, transplants and from mother to child.

The Penn State research team identified 3,521 people infected with babesiosis between October 2015 and December 2022. Most of the cases occurred in the summer in northeastern states.

Forty-two percent of patients with babesiosis had at least one other tick-borne illness—a higher rate than in previous research.

Among these patients, 41% were co-infected with the bacterium responsible for Lyme disease while 3.7% showed signs of ehrlichiosis and 0.3% with anaplasmosis.

Deaths from babesiosis are rare – in 2019, the death rate in the US was 0.57%. Five people died that year in New York, two in Massachusetts and one in Maryland.

Ssentongo said he was surprised that the risk of death was higher in the babesiosis-only group than the co-infection group.

“Having babesiosis and Lyme disease did not seem to be associated with worse mortality,” he said. “It is speculated that the simultaneous presence of other tick-borne infections in the blood may alter the immune response by ‘boosting’ it to effectively fight the infections.”

Symptoms of babesiosis

Some patients with babesiosis may have no symptoms, according to the Centers for Disease Control and Prevention.

Others may develop flu-like symptoms a week after infection or several weeks later. Symptoms include:

• fever
• Chills
• Sweating
• Headache
• Body aches
• Loss of appetite
• nausea
• Fatigue

The disease can be fatal for the elderly and those with a weakened immune system, liver or kidney disease, and/or without a spleen.

“In the young and healthy, the infection is barely noticeable,” Dr. Bruce Hirsch, attending physician in the Northwell Health Division of Infectious Diseases. “For those of us who are older, have illnesses or need treatments that suppress the immune system, or for those of us who no longer have a spleen, babesiosis can be deadly! Another reason to avoid ticks.”

Treatment of babesiosis

A blood test can confirm the presence of the Babesia parasite.

The antibiotics azithromycin and atovaquone usually treat the disease. In severe cases, a process that exchanges abnormal red blood cells for healthy ones may be used.

“For patients with babesiosis, we add doxycycline while we are investigating whether or not the patient has Lyme disease or other tick-borne diseases, and we have seen better outcomes at our medical center with this approach,” Ssentongo said, adding that more research is needed on this method.

How you can prevent babesiosis

“Practice tick bite prevention practices. Wear long-sleeved shirts and pants and light-colored clothes,” advised Ssentongo. “Use tick repellants and check for ticks after spending time outside.”