Humans are the intermediate hosts in which asexual reproduction occurs, and female anopheline mosquitos are the definitive hosts harboring the sexual reproduction stage. An infected female Anopheles mosquito begins the cycle by biting a human. Of about 460 Anopheles mosquito species, 30–40 species transmit Plasmodium falciparum. One of Africa's best-known and most prevalent vectors is the Anopheles gambiae mosquito.
The infective stage, called sporozoites, is released from the salivary glands through the mosquito's proboscis and enters the bloodstream during feeding. The mosquito's saliva contains anti-hemostatic and anti-inflammatory enzymes that disrupt blood clotting and inhibit the pain reaction. On average, each infected bite contains 20–200 sporozoites.
CDC. (2001). Life Cycle of Anopheles Mosquitoes | Mosquitoes | CDC
