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

Dietary analysis Essay Example | Topics and Well Written Essays - 2000 words

Dietary analysis - Essay Example 2.1.2 Fats: fats consist of fatty acids which are made up of long carbon chains bonded together by glycerol. The most common type is three fatty acids bonded to one glycerol backbone and is refereed to as triglyceride. Fats may also be classified as saturated or unsaturated fats. The basis of this classification depends upon the structure of the fatty acid. The saturated fats have their carbon atoms bonded to hydrogen. Unsaturated fats on the other hand have less carbon atoms bonded to the hydrogen. Unsaturated fats are also refereed to as monounsaturated or polyunsaturated. Research indicates that unsaturated fats particularly the monounsaturated fats are best for human consumption. Dieticians also classify fats as essential and non-essential fatty acids. Non essential fatty acids are produced by the body while the essential fatty acids must be included in the diet. Essential fatty acids include omega-3 and omega-6. 2.1.3 Fiber: It is a form of carbohydrate which is absorbed by the body. It produces energy like ordinary carbohydrates but accounts for less energy due to their limited digestibility and absorption rate. Cellulose is the most common fiber. Fibers can be classified as soluble or insoluble fiber. Fiber reduces the risk of colon cancer and aids in digestion reducing diarrhea and constipation. Food containing fiber includes whole grain, fruits such as plums, figs and prunes; and vegetables. 2.1.4 Proteins: The body structure is made of proteins. Skin, muscles, hair and flesh within the human body are made of protein complex. Protein also forms a constituent of all enzymes that control chemical reactions in the body. The chemical reaction enables production of energy and conversion of various chemicals. The protein molecules are made up of amino acid molecules. The human body does require amino acids to