Abstract
A 58-year-old Thai man was infected with Plasmodium knowlesi in Chantaburi Province, eastern Thailand. In addition to pyrexia, the patient developed hypotension, renal failure, jaundice, and severe thrombocytopenia. The parasitemia at the time of admission was 16.67% or ∼503,400 parasites/μL. With artesunate treatment and supportive care, the patient recovered uneventfully. The occurrence of complicated knowlesi malaria in a low-endemic area underscores the risk of high morbidity from this simian malaria.