Coinfection does not affect Babesia results

Adults with Babesia co-infected with tick-borne zoonoses showed no increased risk of mortality or disease severity than those with Babesia based solely on data from more than 3500 people.

Conducting the study was imperative because of the increase in tick-borne infections, said lead author Paddy Ssentongo, MD, of the Division of Infectious Diseases and Epidemiology, Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania.

“If not treated immediately, the consequences are severe, which include serious illness, intensive care unit admissions and even death,” he said. The researchers hypothesized that coinfection with Babesia and other tick-borne pathogens would be associated with greater disease severity and mortality.

In a study published in Open forum infectious diseasesthe researchers reviewed data from 3521 patients with Babesia across the United States. The data came from the TriNetX database for the time between January 1, 1980 and July 24, 2023. The mean age of the patients was 56 years; 51% were male and 78% were white. The primary outcome was 90-day mortality after a diagnosis of Babesia.

Overall, 42% of patients had one or more co-infections. Of these, 41% were co-infected with Borrelia burgdorferi3.7% with ehrlichiosis and 0.3% with anaplasmosis. Patients with co-infections were significantly more likely to receive doxycycline than those with Babesia only (25% vs. 18%; P

In an adjusted analysis, the odds of 90-day mortality were lower in co-infected patients, but the difference was not significant (adjusted odds ratio (aOR), 0.43). Secondary outcomes included acute respiratory distress syndrome, multiorgan failure, and disseminated intravascular coagulopathy. There were no significant differences in any of these outcomes between Babesia-only and coinfection groups (aOR, 1.56; aOR, 0.82; and aOR, 0.99, respectively).

Overall, the most common comorbidities were hypertension (42%), chronic obstructive pulmonary disease (18%), and diabetes (14%). The overall malignancy rate was 19%.

Ssentongo said he was somewhat surprised by the increase in new cases of babesiosis per year and by the high rate of co-infections with other tick-borne diseases, including Lyme disease and anaplasmosis.

The Babesia the infection rate in the United States has increased over the past decade at a rate of at least 9%, Ssentongo said Medscape Medical News. “Important, Babesia infection does not travel alone,” and clinicians should be aware that 4 in 10 patients are co-infected with other tick-borne diseases, each requiring a different treatment, he said.

“Healthcare providers should have a high index of suspicion for the disease in patients with typical symptoms, even if these individuals do not remember a tick bite,” Ssentongo emphasized.

The study’s biggest limitation was the inability to analyze the data separately by state or county, which could have shown hot spots of infection, Ssentongo said. “Another limitation is the lack of blood parasitaemia (the percentage of infected red blood cells), which could have been used to determine the severity of the disease,” he noted.

Looking ahead, more research is needed to determine whether red blood cell exchange improved mortality and outcomes among patients with higher parasite burdens or severe organ dysfunction, Ssentongo said Medscape Medical News. Likewise, “little is known about the long-term consequences of the disease; There are many unanswered questions, such as the long-term effects on the brain,” he noted.

Outcomes data inform care as infection rates increase

“Cases of human babesiosis are increasing in the United States, and this study helped characterize the mortality risk of babesiosis along with tick-borne co-infections,” said Shirin Mazumder, MD, associate professor and specialist in infectious diseases at the University of Tennessee Health Science Center, Memphis, Tennessee , in an interview.

“Since more of the population is experiencing tick-borne infections, it is important to pay attention to the results when tick-borne coinfections are involved,” said Mazumder, who was not involved in the current study.

“The results of this study were surprising to me, as I assumed that patients with Babesia infections that were co-infected with another tick-borne infection would have both higher mortality and disease severity,” Mazumder said Medscape Medical News.

The current study showed that patients with Babesia infections that were simultaneously infected with B burgdorferianaplasmosis and ehrlichiosis did not have a higher mortality rate or more severe disease, Mazumder noted. “Clinicians should have a low threshold to look for other tick-borne co-infections among patients with babesiosis, and presumptive treatment with doxycycline should be considered,” she said.

This study had a low number of co-infections with anaplasmosis and ehrlichiosis, Mazumder said. Asplenia and older age are known risk factors for more severe disease; the average age in the current study was 56 years, and the rate of asplenia was 2%, she said. “It would be interesting to see if a similar study that includes a more advanced age group and higher prevalence of asplenia would yield different results,” she noted.

Another limitation of the study was the inability to include parasitemia in the statistical analysis due to the lack of data from the database used in the study, Mazumder said Medscape Medical News. “Further research looking at parasitemia analysis may be beneficial,” she said. “Looking at complications, such as chronic fatigue, kidney failure and congestive heart disease, among patients with tick-borne co-infections may also be a useful future study,” she said.

The study was supported by start-up funds from the Department of Public Health Sciences, College of Medicine, Penn State, part of a tenure-track professorship package for Ssentongo. The researchers had no financial conflicts to disclose. Mazumder had no financial conflicts to disclose.