Life Cycle
<Infection occurs when a female Anopheles mosquito injects sporozoites while taking a blood meal.
 
<The spozoites move to the liver, enter liver cells and replicate asexually through schizogony.  This is the exoerythrocytic stage.
< Merozoites from the liver infect red blood cells and replicate asexually through schizogony.  This is the erythrocytic stage.
Microscopy of Plasmodium species
< Merozoites continue to burst from RBCs and infect new RBCs in a periodic cycle of 48-72 hours depending on the species. 

< Some parasites will differentiate into the sexual stages, called gametocytes.  The life cycle is continued when an Anopheles mosquito ingests gametocytes during a blood meal.

Symptoms/Pathology

Infection with Plasmodium species leads to chracteristic fever and chills, often accompanied by headaches, muscle soreness, weakness, vomiting and diarrhea.
Other symptoms include an enlarged spleen, anemia, lung or kidney dysfunction and neurological problems.

Infection with Plasmodium falciparum is often the most severe and involves infection in the brain (cerebral malaria), kidney failure, and severe anemia that may lead to death.  Infection with P. vivax often leads to complications of the spleen or spleen rupture.

A dormant stage of P. ovale and P. vivax may remain in the liver for weeks or years after the intial infection.  These parasites may then enter the bloodstream and cause relapses long afterwards.
 

Help / Information
Return to the Plasmodium species PageZOL 316 Parasitology Online
1999 - All rights reserved.  Produced by Brian E. Keas.