Babesia treatment in two travelers.

Babesia malaria confusion is a diagnostic challenge that cost one traveler her life. In this Inside Lyme podcast, I discuss the Babesia treatment of two USA travelers after returning to South Korea—where doctors initially suspected Malaria instead.

Kwon and colleagues describe these cases in the Korean Journal of Parasitology in 2018.

Case 1: Babesia Malaria Misdiagnosis—Patient Survives

The first woman was a 50-year-old housewife who was admitted to a hospital in South Korea with a fever, abdominal pain, and nausea.

She had visited a forest in New Jersey, USA four weeks earlier. She described a reddish skin lesion on the right proximal calf area that was suspicious for a tick bite. Two days later, she developed a headache, muscle soreness, fever, and chills.

If she had remained in the US, doctors would have suspected Lyme disease and co-infections.

But now she had traveled to South Korea. In South Korea, doctors are more likely to suspect Malaria since Malaria is endemic to the northern provinces. She had a blood smear suspicious for Plasmodium species and an infarction of her spleen. She was treated with hydroxychloroquine for Malaria.

The subsequent blood tests did not show Malaria.

The doctors looked again at the blood smear. Four Plasmodium-like organisms looked like a Maltese cross seen in Babesia. This is a ring-like structure in the red blood cell in a tetrad-form resembling a Maltese cross. The PCR test was also positive for Babesia.

The woman was started on Babesia treatment. Her fever, abdominal pain, and lab findings resolved within a day of treatment.

Case 2: Babesia Malaria Confusion—Patient Dies

The second woman was 72 years old. She was evaluated at the same hospital in South Korea with a fever of 99.9°F.

She was moderately anemic with hemoglobin of 10.8 g/dL. Her platelet numbers were low. Her C-reactive protein and sedimentation rate were high, consistent with inflammation.

Malaria-like organisms were described on her blood smear. Her malaria antigen test was negative.

The doctors looked at the blood again. They found Maltese cross forms in the red cells—the same forms described in the first woman.

The doctors prescribed atovaquone 250 mg/proguanil 100 mg and azithromycin 500 mg. This combination is marketed under the names Malarone and Zithromax in the USA.

Her medical condition worsened. She developed a fever, and her lungs were congested.

Her treatment was changed to quinine and clindamycin. This combination has been used for severe cases of Babesia but has more side effects than atovaquone and azithromycin.

She also had a red blood cell exchange. During this procedure, doctors remove abnormal red blood cells and replace them with healthy red blood cells from donors.

Her condition worsened. She was intubated due to respiratory failure.

Doctors added doxycycline for possible co-infection with Lyme disease or Anaplasmosis.

Tests later confirmed the woman had a concurrent infection with Lyme disease. Both the IgG and IgM Western blot tests were positive.

She died 31 days after admittance to the hospital despite treatment—an outcome that echoes other fatal babesia cases where delayed diagnosis proved deadly.

Why Babesia Malaria Confusion Happens

Only eight cases of Babesia infection have been reported in South Korea, 7 of which were imported, notes Kwon.

Both infections show parasites inside red blood cells on blood smear. In areas where Malaria is endemic, doctors naturally suspect it first. But when malaria tests come back negative, Babesia should be considered—especially in patients who traveled to the Northeastern United States.

Kwon cautions both clinicians and travelers: “As the population of traveling abroad increases every year, both physicians and travelers need to be acquainted with not only endemic diseases of their provinces but also with those of other regions.”

This pattern also appeared in other babesia travel cases from Singapore and Spain.

What These Cases Teach Us

Babesiosis can mimic Malaria on blood smear
The onset of Babesia can be delayed—both women developed symptoms weeks after visiting the USA
As the number of international travelers increases, awareness of tick-borne illnesses is critical
Earlier identification of both Babesia and Lyme disease might have saved the 72-year-old woman

Frequently Asked Questions

Why is Babesia confused with Malaria?

Both infections show parasites inside red blood cells on blood smear. In areas where Malaria is common, doctors naturally suspect it first—especially if they’re unfamiliar with Babesia.

How can doctors tell Babesia from Malaria?

The Maltese cross pattern (four parasites in a tetrad formation) is characteristic of Babesia. PCR testing and negative malaria antigen tests can confirm the diagnosis.

Why did the second patient die?

She was 72 years old and had concurrent Lyme disease. By the time Babesia was recognized and treated aggressively, she had developed respiratory failure and multi-organ complications.

Can you get Babesia in South Korea?

Most cases in South Korea are imported from travelers returning from the United States. Babesia is not endemic to South Korea the way Malaria is.

How is Babesia treated differently than Malaria?

Malaria is treated with hydroxychloroquine. Babesia requires atovaquone plus azithromycin, or quinine plus clindamycin for severe cases. Malaria medications don’t work for Babesia.