Babesia After Travel: When It’s Mistaken for Malaria

Babesia after travel can be difficult to recognize—especially in regions where malaria is more familiar.

This is a common diagnostic pitfall in returning travelers.

This is where diagnostic assumptions can lead clinicians in the wrong direction.

Two cases from South Korea highlight how easily Babesia can be missed after travel. :contentReference[oaicite:0]{index=0}

These cases underscore the importance of recognizing tick-borne infections outside endemic regions.

Start here: Babesia overview

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Can Babesia Be Mistaken for Malaria?

Why is Babesia often missed after travel?

Babesia infects red blood cells and can resemble malaria on blood smear.

This overlap can delay diagnosis—especially in countries where malaria is more familiar.

In these cases, both patients were initially suspected of having malaria based on early findings.

However, further testing revealed Babesia microti infection.

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Case 1: Babesia Misdiagnosed After Travel

What happened in the first case?

A 50-year-old woman developed fever, abdominal pain, and muscle aches after returning from New Jersey.

She recalled a skin lesion consistent with a tick bite.

Initial testing suggested malaria, and she was treated accordingly.

When malaria tests returned negative, clinicians re-examined the blood smear.

A Maltese cross pattern—characteristic of Babesia—was identified.

PCR testing confirmed Babesia microti.

After starting Babesia treatment, her symptoms resolved rapidly.

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Case 2: Severe Babesia With Delayed Diagnosis

What happened in the second case?

A 72-year-old woman presented with fever, anemia, and low platelets.

Her blood smear again suggested malaria, but testing was negative.

Further review revealed findings consistent with Babesia.

She was treated with atovaquone and azithromycin but worsened clinically.

Her condition progressed to respiratory failure, requiring intensive care.

Treatment was escalated to clindamycin and quinine, and she underwent red blood cell exchange.

Despite aggressive therapy, she died 31 days after admission.

Later testing confirmed concurrent Lyme disease.

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Why Babesia Diagnosis Can Be Delayed

What makes Babesia difficult to recognize?

• Symptoms overlap with malaria and other infections
• Geographic bias influences diagnostic thinking
• Onset may occur weeks after exposure
• Co-infections such as Lyme disease may complicate the picture

This reflects a broader pattern of delayed diagnosis in tick-borne illnesses.

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Key Lessons From These Cases

What can clinicians and patients learn?

1. Babesia can mimic malaria on blood smear
2. Symptoms may appear weeks after travel
3. Delayed diagnosis can lead to severe outcomes
4. Co-infections can worsen disease severity

Early recognition is critical.

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Why This Matters

What is the broader takeaway?

As international travel increases, physicians must consider infections beyond their local region.

Tick-borne diseases like Babesia are no longer geographically confined.

This is particularly important when symptoms do not respond to initial treatment.

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Clinical Takeaway

Babesia infection should be considered in patients with fever and blood abnormalities after travel—even when malaria is suspected.

A travel history that includes tick exposure can be critical to diagnosis.

If symptoms don’t improve as expected, it’s critical to reconsider the diagnosis early.

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Related Reading

• Babesia symptoms
• How serious is Babesia?
• Treatment for relapsing Babesia
• Babesia symptoms and presentations

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References

1. Kwon HY, Im JH, Park YK, Durey A, Lee JS, Baek JH. Two imported cases of babesiosis with complication or co-infection with Lyme disease in Republic of Korea. Korean Journal of Parasitology. 2018;56(6):609–613.

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Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention