Dual threat: Plasmodium vivax malaria and Dengue co-infection in a traveler to the tropics

Malaria and dengue (MD) co-infection presents a diagnostic challenge due to overlapping clinical features. We report a case of a 62-year-old Italian traveler who developed fever, mild anemia, leukopenia, and severe thrombocytopenia during his stay in eastern Indonesia. Initial testing confirmed dengue virus infection, but persistent fever and worsening hematologic findings prompted a repeated blood film test for malaria parasite, which revealed a Plasmodium vivax co-infection. The patient was managed with intravenous fluids and antipyretics for dengue, followed by dihydroartemisinin/piperaquine and primaquine for P. vivax malaria. His condition improved significantly, and he was discharged with continued anti-relapse therapy. This case highlights the need for high clinical suspicion of MD co-infection in any febrile patient living in or returning from endemic regions. Preventive measures, including malaria chemoprophylaxis and vector control, should be emphasized for travelers to the tropics.