Plasmodium Knowlsei in Thick and Thin Films

Plasmodium Knowlsei in Thick and Thin Films

Thin Smear: P. Knowlsei Ring-form

Background Information of Plasmodium Vivax

Plasmodium knowlesi is a formerly known as a primate malaria parasite commonly found in Southeast Asia. that inflicts malaria in long-tailed macaques, but unfortunately, their incidence in humans are emerging to become the sixth major human malaria parasite (following the division of Plasmodium ovale into 2 species). The transmission of this malarial parasite via Anopheles mosquito may cause severe malaria as indicated by its asexual erythrocytic cycle of about 24 hours, along with an associated fever that typically occurs at the same frequency (i.e. the fever is quotidian) It accounts for up to 70% of malaria cases in certain areas in South East Asia where it is commonly found and is the most common cause of malaria in childhood in the Kudat district of Sabah, Malaysia. 

Symptoms typically surface approximately 11 days after an infected mosquito has bitten a host (Incubation time) and the parasites can be seen in the blood between 10 – 12 days after infection. The parasite may then multiply rapidly resulting in very high parasite densities that may be fatal

Cellular Description

The appearance/morphology of P. knowlesi is synonymous to that of P. malariae and is unlikely to be correctly distinguished/diagnosed unless using PCR assay and/or molecular characterization assays are avaialble.

 

P. malariae is characterized by a compact parasite (all stages) and does not alter the host erythrocyte's shape or size or cause enlargement. Elongated trophozoites stretching across the erythrocyte, called band forms, are sometimes observed. Schizonts will typically have 8-10 merozoites that are often arranged in a rosette pattern with a clump of pigment in the center.