Babesiosis HIV

Can false-positive HIV results come from a tickborne illness? A recent case study investigates.


According to the CDC, the number of reported tickborne diseases more than doubled between 2004-2016 and accounted for > 60% of all reported mosquito-borne, tickborne, and fleaborne disease cases. Which is why it is important to keep an eye out for anyone who has a history of being in a tick-promoting environment. Clinicians from Lehigh Valley Health Network Pocono and Geisinger Commonwealth School of Medicine, both in East Stroudsburg, Pennsylvania, report on a patient whose diagnosis turned on that fact.

The patient, a 71-year-old man, had fever, weakness, headaches, near syncope, and nausea for 4 days. He also had not been eating well.

A complete blood count showed pancytopenia with an excess of band cells, an indicator of inflammation and infection. The patient’s aspartate transaminase levels were elevated. The diagnostic dilemma centered on these findings: Serology tests for HIV 1 and 2 were positive, and a peripheral blood smear showed 0.5% parasitemia consistent with Babesia microti. Both babesiosis and HIV were among the possible diagnoses. Two important factors the clinicians had to consider: The patient had recently been bitten by ticks and was homosexual.

The clinicians note that a variety of infections can lead to false-positive HIV serology, such as malaria, Mycobacterium tuberculosis or Rickettsia species, influenza and hepatitis B vaccinations. Moreover, the Ixodes tick, the same vector that transmits Borrelia burgdorferi , which causes Lyme disease, also transmits B microti . Conversely, HIV infection can exacerbate Lyme disease or babesiosis.

The tests showing B microti were the clincher for the clinicians, who started treatment with fluids, atovaquone, and azithromycin. The patient recovered completely. Repeat HIV serology was negative.

The authors of the report note that babesiosis can be a life-threatening infection in patients with reduced immunity. It is possible that, like malaria and HIV serologies, Babesia and HIV serologies cross-react, the clinicians say. Thus, it is important to screen for both in both infections.

This is the first case, to the clinician’s knowledge, of HIV associated with active babesiosis

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