Lecture 12: Plasmodium & Malaria Flashcards
How many Plasmodium species cause malaria in humans? Name them.
5 species: P. falciparum, P. malariae, P. vivax, P. ovale, P. knowlesi.
What is the vector for Plasmodium?
Female Anopheles mosquitoes (transmits via saliva during blood meal).
What are the 3 life cycle stages of Plasmodium?
Exo-erythrocytic (liver), erythrocytic (RBCs), sporogonic (mosquito gut → saliva).
What are hypnozoites, and which species form them?
Dormant liver-stage parasites; only P. vivax and P. ovale.
Why does malaria cause fever?
Inflammatory cytokines released when infected RBCs burst.
What makes P. falciparum severe?
PfEMP1 proteins cause cytoadherence (rosetting), blocking spleen clearance → organ damage.
What do var, stevor, and rif genes encode?
var: PfEMP1 (adhesion); stevor: STEVOR (rosetting); rif: RIFIN (immune evasion).
How does PfEMP1 aid immune evasion?
Binds endothelial receptors (e.g., CD36, ICAM-1), preventing spleen filtration.
What are the WHO-recommended diagnostic methods for malaria?
Light microscopy (blood smears) and rapid diagnostic tests (RDTs).
What does PfHRP2 detect in RDTs, and what’s its limitation?
Detects P. falciparum; persists post-infection, causing false positives.
What drug treats hypnozoites (radical treatment)?
Primaquine or tafenoquine (P. vivax/P. ovale only).
Why is artemisinin (e.g., artesunate) first-line for severe malaria?
Rapidly reduces parasite load; IV administration critical for organ failure.
What is the RTS,S/AS01 vaccine’s target?
P. falciparum CSP protein to block liver-stage infection. Efficacy: ~36% over 4 years.
Name 3 non-drug prevention methods.
DEET repellents, insecticide-treated nets, covering skin at dusk/dawn.
