Study Reveals Rising Rates of Babesiosis and Co-Infections with Lyme Disease
October 2024 — Penn State Health Milton S. Hershey Medical Center and Penn State College of Medicine have sounded the alarm on the rising rates of babesiosis, a parasitic tick-borne disease commonly referred to as “American malaria.” A recent study published in Open Forum Infectious Diseases shows that cases of babesiosis have increased by an average of 9% annually between 2015 and 2022, with nearly half of those infected also co-infected with other tick-borne diseases, including Lyme disease.
Babesiosis is transmitted by black-legged ticks and affects red blood cells, leading to flu-like symptoms that can be severe or even fatal for high-risk groups, such as the elderly and those with weakened immune systems. The disease has been primarily confined to the Northeastern and Midwestern United States, but with its rising prevalence, health experts are raising concerns about the broader implications for public health.
A Growing Concern
The study analyzed over 3,500 cases of babesiosis and found that the disease’s incidence is most pronounced in the summer months. While the number of cases is climbing, what’s even more concerning is the prevalence of co-infections. Forty-two percent of individuals diagnosed with babesiosis also tested positive for another tick-borne disease, with Lyme disease being the most common co-infection. This marks a significant increase in co-infection rates compared to previous years.
“The co-infection with Lyme disease and babesiosis has become a notable concern for clinicians,” said Dr. Paddy Ssentongo, the study’s lead author and infectious disease fellow at Penn State Health Milton S. Hershey Medical Center. “Ticks carry not only the Babesia parasite but also other pathogens like Lyme disease, anaplasmosis, and ehrlichiosis, which complicates diagnosis and treatment.”
Climate Change as a Possible Culprit
Experts believe that environmental factors such as climate change may be contributing to the surge in tick-borne diseases. Rising temperatures, altered rainfall patterns, and extended seasons have expanded the range of ticks, allowing them to thrive in areas previously unaffected by these pathogens.
“The climate shifts are creating a more favorable environment for ticks and the animals that harbor them,” Dr. Ssentongo explained. “As a result, we are seeing more cases of babesiosis in regions where it was once rare.”
The Impact of Co-Infections on Mortality
One of the most surprising findings of the study was the impact of co-infections on patient outcomes. While co-infected patients showed no significant difference in complications compared to those with babesiosis alone, the mortality risk for those with babesiosis without co-infections was found to be higher. This raises intriguing questions about how the immune system responds to concurrent tick-borne infections.
“Having Lyme disease alongside babesiosis did not seem to worsen the mortality risk,” said Dr. Ssentongo. “This could suggest that co-infections might modulate the immune system in a way that helps fight off the infections more effectively.”
However, the research also indicated that the co-infected group was more likely to receive doxycycline—an antibiotic used to treat Lyme disease, anaplasmosis, and ehrlichiosis—raising the possibility that this treatment might also play a role in improving outcomes for babesiosis patients.
Treatment and Prevention: The Key to Combatting Babesiosis
Treatment for babesiosis varies depending on the severity of the disease. Mild cases can be treated with antibiotics such as azithromycin and atovaquone, while severe cases may require more aggressive treatments, including red blood cell exchange. However, the role of doxycycline in treating babesiosis remains uncertain, and further research is needed to explore its efficacy.
Prevention remains the best strategy to reduce the risk of babesiosis and other tick-borne diseases. Experts recommend wearing long-sleeved clothing, using tick repellents, and checking for ticks after outdoor activities, particularly during the summer months when ticks are most active.
“The key is prevention,” said Dr. Ssentongo. “If you live in areas where babesiosis is endemic, take measures to protect yourself and your family from tick bites. This is especially important in the Northeastern and Midwestern states, where the risk is highest.”
Conclusion
As tick-borne diseases continue to rise, public health experts urge increased vigilance among clinicians and the public. With climate change influencing the spread of ticks and their pathogens, addressing this growing threat will require a combination of preventive measures, improved treatments, and ongoing research into the dynamics of co-infections.