Should DDT Be Used to Control Malaria Essay Example | Topics and Well Written Essays - 750 words

Should DDT Be Used to Control Malaria - Essay Example falciparum), Plasmodium malariae (P. malariae), Plasmodium ovale (P. ovale) and Plasmodium vivax (P. vivax). due to P. falciparum which is the only species associated with severe morbidity and mortality (Guidelines, South Africa). The other three species cause milder illness. Infections with P. ovale and P. vivax have a tendency to relapse if timely appropriate treatment is not provided (CDC, U.S). The life cycle of the malaria parasite involves two hosts- the mosquito and the human. When a female anopheles infected mosquito bites a human for blood meal, it inoculates sporozoites into the human host. These sporozoites infect liver cells1, multiply and mature into schizonts, which rupture and release a number of merozoites into the blood stream where they infect red cells and cause symptoms of the disease like fever, chills, tiredness and muscular pain. In P. vivax and P. ovale malaria infections, a dormant stage can persist in the liver of the human in the form of hypnozoites. These can later invade blood stream, weeks, or even years later, and cause relapse. In the red cells2, the parasites undergo asexual multiplication. Initially, the merozoites turn in to ring stage trophozoites which mature into schizonts. These rupture to release merozoites. Some parasites differentiate into gametocytes (sexual erythrocytic stages) which in turn produce the male (microgametocytes) and fe male (macrogametocytes) gametocytes. These are ingested by a female anopheles mosquito during a blood meal and they multiply in the mosquito releasing sporozoites which settle in the salivary glands and enter the human host during biting. The multiplication in the mosquito is known as the sporogonic cycle. Thus the mosquito carries the disease from one human to another, acting as a "vector" (Guidelines, South Africa). Of the 430 known species of anopheles mosquito, only 30 to