A Case of Imported Plasmodium Falciparum Infection in Shaoxing

Malaria is a vector-borne infectious disease caused by the bites of female mosquitoes infected with Plasmodium on humans. In China, imported Plasmodium is the main type, among which falciparum malaria has the most severe symptoms. Improving the diagnostic ability of microscopic examination of Plasmodium in the laboratory is of great significance for early diagnosis and treatment of patients.

Thick and thin blood smears were made from peripheral blood and stained with Riez-Giemsa staining. The malaria parasites were searched for under an oil immersion microscope to distinguish the morphology of different species. The specific antigens of Plasmodium in the whole blood samples of patients were detected by the rapid diagnostic test for Plasmodium (RDT). The scatter plot of peripheral blood white blood cells can indicate the presence of infected red blood cells and can be used for auxiliary diagnosis. Fluorescence quantitative PCR can identify the species of Plasmodium.

Plasmodium ring-shaped bodies can be seen on the thick blood membrane of peripheral blood. Infected red blood cells can be seen on the thin blood membrane, which are about the same size as or slightly smaller than normal red blood cells. Ring-shaped bodies can be seen inside the red blood cells, and some of the ring-shaped bodies have binuclear nuclei. Occasionally, Plasmodium gametes can be seen, which are crescent-shaped or sausage-shaped. The RDT result of this patient suggests a single or mixed infection of falciparum malaria. The patient was diagnosed with Plasmodium falciparum infection by fluorescence quantitative PCR detection and morphological analysis by the Center for Disease Control and Prevention. The patient was treated with two tablets of dihydroartemisinin piperquine.

Plasmodium falciparum infection is relatively rare in Shaoxing area, and laboratory tests are prone to missed diagnosis. Continuously enhancing the ability of laboratory technicians to identify the morphology of Plasmodium can provide certain assistance for early clinical diagnosis and treatment.