Falciparum Malaria Incidentally Pretreated with Azithromycin

Area of Science:

• Tropical Medicine
• Infectious Diseases
• Clinical Diagnostics

Background:

• Travelers returning from malaria-endemic regions, such as Liberia, are at risk for Plasmodium falciparum infection.
• Fever is a common presenting symptom requiring prompt diagnosis and treatment.
• Azithromycin is frequently prescribed for various infections, including in travelers.

Observation:

• A 65-year-old man with fever after returning from Liberia received azithromycin.
• Subsequent blood smear examination for malaria was negative.
• A rapid antigen test was strongly positive for falciparum malaria.

Findings:

• The negative blood smear result was likely a false negative, potentially due to partial treatment by azithromycin.
• The high level of malarial antigen detected by the rapid test indicated active falciparum malaria.
• Laboratory parameters showed improvement upon hospital admission.

Implications:

• Azithromycin administration may interfere with the diagnostic accuracy of malaria blood smears.
• Clinicians should exercise caution when prescribing azithromycin to travelers from malaria-endemic areas.
• Consider alternative diagnostic methods or further testing when malaria is suspected despite negative blood smears after azithromycin use.