Mosquito Bite
P. falciparum is transmitted to humans by the females of the Anopheles species of mosquito. There are about 460 species of Anopheles mosquito, but only 68 transmit malaria. Anopheles gambiae, found in Africa, is one of the best malaria vectors. It is long-lived, prefers feeding on humans, and lives in areas near human habitation.
Prior to transmission, Plasmodium falciparum resides within the salivary gland of the mosquito. The parasite is in its sporozoite stage at this point. The Pumilio-FBF family member Puf2 appears to be critical for its survival in the mosquito salivary gland.
As the mosquito takes its blood meal, it injects a small amount of saliva into the skin wound. The saliva contains antihemostatic and anti-inflammatory enzymes that disrupt the clotting process and inhibit the pain reaction. Some of the details of this process are known. A salivary protein - anophelin - is a powerful thrombin inhibitor. This protein occupies thrombin's active site but is highly resistant to cleavage by the enzyme.
Typically, each infected bite contains 5-200 sporozoites which proceed to infect the human vector. Once in the human bloodstream, the sporozoites only circulate for a matter of minutes before infecting liver cells.
~1900 proteins have been reported from sporozoites infecting the salivary glands.
Read more about this topic: Plasmodium Falciparum Biology
Famous quotes containing the word bite:
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—William Shakespeare (1564–1616)