Malaria is caused by Plasmodium parasites, transmitted by female Anopheles mosquitoes. The main species causing malaria in humans are:
1. Plasmodium falciparum: Most severe, can cause cerebral malaria.
2. Plasmodium vivax: Causes relapses due to liver hypnozoites.
3. Plasmodium ovale: Similar to P. vivax, but less common.
4. Plasmodium malariae: Can cause chronic infection.
5. Plasmodium knowlesi: Zoonotic malaria, found in Southeast Asia. (Etiology of Malaria)
Transmission & Life Cycle
1) Mosquito Stage
The mosquito injects sporozoites into the human bloodstream during a bite.
2) Liver Stage (Pre-Erythrocytic Stage)
Sporozoites invade liver cells, multiply, and form merozoites.
3) Blood Stage (Erythrocytic Cycle)
Merozoites infect red blood cells (RBCs), multiply, rupture RBCs, and cause fever.
4) Gametocyte Formation
Some parasites develop into gametocytes, which are taken up by a mosquito.
5) Mosquito Cycle
Gametocytes mature into sporozoites, completing the cycle.
Symptoms of Malaria
High fever, chills, sweating (classic tertian or quartan fever cycles)
Headache, muscle pain, fatigue
Severe malaria (P. falciparum) → Organ failure, coma, death
Prevention & Treatment
Prevention: Mosquito control (nets, repellents), prophylactic drugs (chloroquine, doxycycline).
Treatment: Antimalarial drugs (artemisinin-based combination therapies, chloroquine, mefloquine).
