Schizont

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QUESTION

What is a schizont?

ANSWER

A schizont is a malaria parasite which has matured and contains many merozoites, which are the parasite stage that infects red blood cells.

Schizonts can be produces during two separate phases of the life cycle within the human host: first in the hepatocytic cells in the liver (when sporozoites mature) during the exo-erythrocytic cycle and then within the red blood cells during the erythrocytic cycle (when trophozoites mature and divide).

When malaria parasites do not immediately mature into schizonts in the liver (as can be the case with Plasmodium vivax and P. ovale infections), the parasite instead becomes a hypnozoite, which can lay dormant in the liver for many weeks or even months (or, in rare case, years), and produce relapse of infection at a much later date.

Primaquine for Malaria Treatment

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QUESTION:

In India what is the duration of primaquine therapy in confirmed Malaria infection?

ANSWER:

Primaquine is usually used to kill the hypnozoite stages of Plasmodium vivax or P. ovale. This life stage of the malaria parasite can reside, dormant in the liver’s hepatocyte cells, even after the patient has completed the normal course of treatment for the infection; at this stage, the patient might not have visible malaria parasites in the bloodstream, and thus be considered “cured”. Despite this, the patient is actually potentially at risk from recurrence of malaria if the dormant liver hepatocytes re-enter the blood stream.

For this reason, patients with P. vivax or P. ovale should complete a course of primaquine in addition to the standard malaria treatment offered. The usual adult dosage for primaquine is 15-30mg base, taken orally, once a day for 14 days.