Plasmodium: Two Hosts, One Fever Clock

In the paper

Unit 4 (Study of Selected Animals) carries 6 of the 40 zoology marks, and with three chapters sharing them, Plasmodium averages about two (MEC publishes weights by unit, not by chapter). The MEC scope line is short: Habitat, Structure, Life cycle, Types of malaria. The paper is set 50:30:20 (recall : understanding : application), and this chapter is asked in four recognisable ways:

• Recall — the infective stage to man, the host in which the sexual cycle runs, who discovered what and when, which species causes quartan fever.
• Understanding — why the fever returns every 48 hours, why P. vivax relapses after apparent cure but P. falciparum does not, why the mosquito is the definitive host even though the human is the one who falls ill.
• Application — a short case: a returnee from the Terai with fever every third day, a blood film showing banana-shaped gametocytes, a patient who was cured and became ill again eight months later without a new bite.
• Naming the stage from its location — "the stage found on the outer wall of the mosquito stomach is..." (oocyst).