In Vitro Exflagellation of Plasmodium vivax
After recently arriving in Switzerland seeking asylum, a 24-year-old man from Eritrea presented to the emergency department with recurrent fevers. He reported having had fevers approximately every 2 months for the previous 3 years. Physical examination and routine blood tests revealed mild anemia and elevated aminotransferase levels. A rapid antigen-detection test was positive for malaria. A blood smear revealed malarial ring forms as well as flagellated organisms. There was an initial concern about coinfection with another parasite, such as microfilaria, or spirochete, such as borrelia, but the organisms were correctly identified as exflagellated microgametocytes of Plasmodium vivax. Exflagellated plasmodium parasites are normally present only inside the mosquito but can be seen in a blood smear if the blood is exposed to air for some time. The patient was treated with artemether–lumefantrine and primaquine, and he had no recurrent fevers in 6 months of follow-up.