A malaria-like disease is creeping through some parts of the US—and you might be missing it
Key Takeaways
Industry Buzz
"Babesia infection seems to spread where Lyme infection is already present." — Shannon LaDeau, PhD, disease ecologist at the Cary Institute of Ecosystem Studies
"Jurisdictions in the southern mid-Atlantic region should expect babesiosis cases. Tick range expansion is occurring at such a precipitous rate that public health guidance regarding tick-borne disease prevention and treatment can be rapidly rendered obsolete.” — Authors, Journal of Medical Entomology
Lyme disease gets all the headlines. But another tickborne illness—babesiosis—is making quiet gains across Delaware, Maryland, and Virginia. And many physicians aren’t thinking to test for it.
Why it’s flying under the radar
Babesiosis, a malaria-like illness caused by Babesia microti, is transmitted by the same Ixodes scapularis ticks that carry Lyme. The problem? It's far less well-known, less frequently tested for, and often asymptomatic or mild—until it’s not.
The CDC recently added Delaware, Maryland, and Virginia to the list of states where babesiosis is endemic. That shift should give clinicians pause.
If your patients are presenting with nonspecific flu-like symptoms and you’re only testing for Lyme, you may be missing a key piece of the diagnostic puzzle.
Clinical clues
Unlike Lyme, babesiosis infects red blood cells, leading to symptoms that can mimic malaria—think:
Fever and chills
Fatigue and myalgias
Hemolytic anemia
Thrombocytopenia
Elevated LFTs
Immunocompromised patients, those without spleens, and the elderly are most vulnerable. Severe cases can progress to acute respiratory distress, organ failure, or death.
Diagnosis and treatment
Babesiosis won’t show up on a Lyme panel. It requires blood smear microscopy, PCR testing, or serology, depending on the stage and presentation.
Treatment typically involves atovaquone plus azithromycin, or clindamycin plus quinine in severe cases.
What to do next
If you're practicing in or near the Mid-Atlantic—or seeing patients who travel there—keep babesiosis on your radar. Add it to your differential for summer flu-like illness, especially in patients with outdoor exposure, comorbidities, or worsening anemia.
Related: Incidence of tickborne diseases doubles in the US: What you need to know