Mixed Plasmodium vivax and falciparum Malaria in a Young Infant: The Critical Role of Peripheral Smears in an Endemic Region.

Malaria remains a major global public health challenge, particularly in endemic regions and among travelers. Mixed-species malarial co-infections in these areas are frequently underdiagnosed or underestimated due to their lower incidence, especially in vulnerable pediatric populations. Such co-infections often result in severe complications and delayed targeted therapy. Here, we report the case of an 18-month-old male infant who presented with a low-grade fever, abdominal pain, severe anemia, and hepatosplenomegaly. Given the regional endemicity and season, Plasmodium vivax infection was initially suspected, and empirical treatment was initiated. However, a peripheral blood smear subsequently revealed a mixed infection with Plasmodium falciparum, necessitating an immediate adjustment in the therapeutic regimen. Following the targeted intervention, the patient demonstrated significant clinical and hematological recovery. This case emphasizes the critical importance of considering mixed plasmodial co-infections in pediatric patients presenting with non-specific symptoms and rapid clinical deterioration in endemic areas. Microscopic examination of peripheral smears by a trained pathologist remains the gold standard for early identification, which is essential to secure favorable outcomes in complex pediatric cases.