Q.Explain the biological control of mosquitoes as a method of malaria control.

Plasmodium vivax is a digenetic sporozoan parasite that causes vivax (benign tertian) malaria in humans, requiring two hosts to complete its life cycle: humans, in which only asexual multiplication (schizogony) occurs, and the female Anopheles mosquito, in which the sexual phase (gametogony and sporogony) occurs.

In man — exo-erythrocytic (hepatic) cycle. An infective mosquito bite injects sporozoites into the blood; these invade liver cells (hepatocytes) and multiply asexually by schizogony into cryptomerozoites. The time from the infective bite to the first appearance of parasites in blood is the prepatent period; some sporozoites remain dormant in the liver as hypnozoites, which can reactivate later and cause relapses long after apparent recovery. …