Parasitic wasps



Introduction

Malaria is one of the most prevalent and dangerous diseases known to man. It has existed for centuries and affects a myriad of people in the tropical region. Even today, with our newly discovered treatments for many of the tropical diseases, over 10% of the people that are infected with malaria each year and do not receive proper treatment die. In Africa alone, over 1 million children die each year because of malaria and new cases are reported frequently. Malaria is very dangerous and harmful to man.


However, the protozoan that causes malaria has existed since man came into being. Fossils of mosquitoes that are 30 million years old contain the vector for malaria. After written history, many civilisations have known about malaria. The Greek physician Hippocrates described the symptoms of malaria in the 5th Century BC The name malaria is derived from the Italian words, mal and aria, meaning "bad air", because people of earlier times believed that the disease was caused by polluted air near swaps and wetlands in Europe. The scientific identification of malaria was not found until 1880. The French army physician, Charles Laveran, while stationed in Algeria, noticed strange shapes of red blood cells in certain patients and identified the disease scientifically and linked to a certain protozoan. Although the disease had been identified, it was not until 1897, when British army physician, Ronald Ross studied birds and discovered that the malarial protozoan was transmitted through mosquitoes. Soon after, two Italian scientists noted that mosquitoes spread malaria to humans as well. Many attempts have been made to try to eradicate the disease. As early as 7 AD, in Rome, swamps were drained to try to prevent the "bad air" from reaching nearby cities. Recently, in the 1950\'s and 1960\'s, about 25 years after the development of DDT, the United Nations World Health Organisation tried to wipe out the disease through the use of DDT. Although, the number of cases was reduces in many areas, they started again. Scientists today believe that malaria can never be eradicated due to the fact that the protozoan can manipulate easily and become resistant to a drug that is overused. The mosquitoes that spread malaria are also becoming resistant to insecticides. Malaria can be treated on an individual basis and treatments and medicines can be used.
To understand these treatments however, one must understand what happens to a malarial protozoan. The disease, malaria, is cause by the protozoan, Plasmodium, which lives in tropical regions all around the world. There are only four species of this protozoan that cause malaria in humans, Plasmodium ovale, Plasmodium vivax, Plasmodium malariae, and Plasmodium falciparum. These protozoans are spread from infected to healthy people through the bite of the Anopheles mosquito, blood transfusions, or through hypodermic injections. This makes malaria one of the most easily communicable diseases in the world.


1.Sporozoites in salivary gland.
2.O÷cysts in stomach wall.
3.Male and female gametocytes.
4.Liver phase.
5.Release of merozoites from liver.
These enter red cells where both sexual and asexual cycles continue.


Malaria is spread only through the females of the 60 different types of the Anopheles mosquito, as the males do not feed on blood. The symptoms of this disease are many, however a physician must be consulted to avoid risk to a person.
To treat malaria, many drugs are used today. Forms of these drugs date back to the 1500\'s and 1600\'s. Physicians diagnose malaria by identifying Plasmodia in a patient\'s body. Once identified, malaria can be treated with chloroquine and primaquine. Since some forms of Plasmodia falciparum have become resistant to these, quinine, mefloquine, or halofautrine are used. Almost all of the cases of malaria can be treated if done in the proper way. However, to suffer the pain and illness of malaria, people can use many preventive measures. All swampy areas must be avoided as well as tropical water that may be contaminated or local food. People should just protect themselves from mosquitoes and risk of infection will be tremendously lowered. This can be done by impregnated bednets. These involve surrounding the bed with a curtain that is sprayed with certain compounds. These are normally pyrethroids or organophosphates, which create an effective barrier between the mosquito and its blood meal. Alternative \'barrier\' methods are insect repellents. These are certain chemicals that that