ABSTRACT
There are four species of the parasite Plasmodium which are responsible for causing malaria in humans. They are P.falciparum, P.vivax, P. malariae and P.ovale. Female anopheline mosquitoes infected with Plasmodium sporozoites transfer the Plasmodium sporozoites to the blood of humans by bites. In the initial stage (the pre-erythrocytic phase), the sporozoites disappear from the blood and invade the liver. The malaria symptoms are not apparent at this stage. Merozoites released from the liver then invade the erythrocytes, thereby starting the blood cycle. The merozoites in the erythrocytes are transformed into trophozoites. On asexual reproduction of trophozoites, schizoites are formed which burst, thereby affording many more merozoites which again infect more erythrocytes, thereby multiplying the number of infected erythrocytes. When the erythrocytes burst, an intense feeling of cold is produced in the patient, causing shivering. Some of the merozoites then become differentiated into male and female gametocytes which cannot develop further in the human being and must be transferred to the female Anopheles mosquitoes gut where the sexual phase of the life cycle of the malarial parasites takes its course [Gupta, 1995].
