Plasmodium Vivax in Thick and Thin Films

Plasmodium Vivax in Thick and Thin Films

 

Thin Smear

Background Information of Plasmodium Vivax

Plasmodium Vivax is the most common and widely distributed protozoal parasite that infects humans, but fortunately it is the less virulent than Plasmodium Falciparum. P. vivax is carried by the female Anopheles mosquito, since it is only the female of the species that bite. The West Africans are almost safe from this infection as their RBCs do not posses Duffy Antigen  which is the mode of RBC infection. It has an incubation period of 10-17 days and a periodicity of 48 hours

Cellular Description

Schüffner's dots in Thin Smear

 

The hall mark of Plasmodium Vivax infection is enlarged RBCs that maybe round/oval  but often adopting bizarre shapes due to parasitic activity. Presence of Schüffner's dots (golden brown/pinkish-red) scattered through out the RBC cytoplasm is a signature characteristic to this species.  

The parasite within it is often wildly irregular in shape (described as "amoeboid"). Schizonts of P. vivax have ~20 merozoites within them. It is rare to see cells with more than one parasite within them. Merozoites will only attach to immature blood cell (reticulocytes) and therefore it is unusual to see more than 3% of all circulating erythrocytes parasitised.