Severe Malaria Due to Plasmodium vivax With Pulmonary Involvement: A Case Report

Malaria is a disease caused by Plasmodium parasites and spread through the bites of female Anopheles mosquitoes. Although Plasmodium falciparum remains the primary species causing severe malaria, Plasmodium vivax is increasingly recognized, and its latent forms can reactivate months to years after exposure. A 46-year-old woman from India, who had traveled to Portugal for six months, was admitted to the emergency department with asthenia and fatigue for three days. On examination, she was febrile and hypoxemic. Additional evaluation revealed severe anemia, thrombocytopenia, and extensive areas of ground-glass opacification on chest tomography. She was admitted to the ICU and required high-flow oxygen therapy. During further evaluation, P. vivax was identified, with a parasitemia of 50% and a parasite density of 8,645 parasites/µL. Due to the unavailability of IV artesunate, treatment was initiated with artemether-lumefantrine and doxycycline, resulting in progressive improvement and successful oxygen weaning. By the third day of treatment, parasitemia had cleared. This case underscores the need for high clinical suspicion for P. vivax malaria in patients with relevant epidemiological exposure.