Afebrile falciparum malaria with severe hemolytic anemia in a returning traveler: a case report

Malaria classically presents with fever, however, atypical afebrile presentations can lead to significant diagnostic delays, particularly in non-endemic regions. We report an unusual case of afebrile Plasmodium falciparum malaria presenting primarily as severe hemolytic anemia in a returning traveler. A 45-year-old Chinese man presented with a 12-day history of persistent dizziness, fatigue, and poor appetite. Upon transfer to our hospital, he developed acute confusion and quadriparesis. Laboratory tests revealed severe hemolytic anemia (hemoglobin 48 g/L), thrombocytopenia, and intravascular hemolysis. The patient remained afebrile throughout his illness. Neuroimaging ruled out acute intracranial pathology. Diagnosis was confirmed by peripheral blood smear showing P. falciparum (0.9% parasitemia, approximately 1746 parasites/µL), supported by HRP-2 antigen testing and PCR. Treatment with intramuscular artesunate followed by oral dihydroartemisinin-piperaquine led to full recovery and parasite clearance. This report demonstrates that malaria can present as severe hemolytic anemia without fever. In elimination settings, heightened clinical suspicion and routine peripheral blood smear examination are essential for timely diagnosis in at-risk returned travelers. This case reinforces the need to maintain diagnostic vigilance for afebrile malaria, even in non-endemic regions.