Parasitology Diagnostic Laboratory

Plasmodium vivax

The image below is a Giemsa-stained thin blood smear of a Plasmodium vivax trophozoite. This species accounts for as much as 80% of all malaria, and is also the most widely distributed. Infected red blood cells (RBC) are usually enlarged and paler staining than uninfected ones. RBC may also contain a stippling of reddish-purple Schüffner's dots, and the trophozoites inside the RBC are typically amoeboid with a single chromatin dot (DNA). Occasionally cells will contain more than one parasite. Mature schizonts contain 12-24 merozoites with rather diffuse pigment. Gametocytes are large, round and fill the entire red blood cell. The chromatin dot is single and well-defined, whereas the pigment is fine and scattered.