<P> Humans are the intermediate hosts in which asexual reproduction occurs, and female anopheline mosquitos are the definitive hosts harbouring the sexual reproduction stage . </P> <P> Infection in humans begins with the bite of an infected female Anopheles mosquito . Out of about 460 species of Anopheles mosquito, more than 70 species transmit falciparum malaria . Anopheles gambiae is one of the best known and most prevalent vectors, particularly in Africa . </P> <P> The infective stage called sporozoites released from the salivary glands through the proboscis of the mosquito enter the bloodstream during feeding . The mosquito saliva contains antihemostatic and anti-inflammatory enzymes that disrupt blood clotting and inhibit the pain reaction . Typically, each infected bite contains 20 - 200 sporozoites . The immune system clears the sporozoites from the circulation within 30 minutes . But a few escape and quickly invade liver cells (hepatocytes). The sporozoits move in the blood stream by gliding, which is driven by motor made up of proteins actin and myosin beneath their plasma membrane . </P> <P> Entering the hepatocytes, the parasite loses its apical complex and surface coat, and transforms into a trophozoite . Within the parasitophorous vacuole of the hepatocyte, it undergoes 13 - 14 rounds of mitosis and meiosis which produce a syncytial cell (coenocyte) called a schizont . This process is called schizogony . A schizont contains tens of thousands of nuclei . From the surface of the schizont, tens of thousands of haploid (1n) daughter cells called merozoites emerge . The liver stage can produce up to 90,000 merozoites, which are eventually released into the bloodstream in parasite - filled vesicles called merosomes . </P>

Plasmodium falciparum is described as the causative agent of malaria