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Mosquito nets save lives
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The Info Box
Malaria - threat from single-celled organisms
The vectors of malaria are tiny single-celled organisms belonging to the genus Plasmodium, four of whose numerous species can attack humans. But only Plasmodium falciparum, the multifaceted pathogen of malaria tropica, became the fatal scourge of mankind.
Development in humans
Plasmodia are transmitted by the saliva of an infected mosquito vector of the genus Anopheles, enter the blood stream in the form of sporozoites, and then penetrate into the cells of liver tissue where they multiply by division. In this way, every single sporozoite produces up to 30,000 merozoites which finally cause the host cell to rupture. The pathogens thereby released now attack and penetrate other red blood cells in which they continue to multiply. The dying red blood cells release increasing numbers of pathogens which in turn attack other healthy cells. A small portion of the merozoites then develop into male and female gametocytes. The next time the mosquito bites a human, the gametocytes can enter the mosquito's intestine where the parasites reproduce sexually. This results in the formation of up to 1,000 new sporozoites that penetrate into the insect's salivary glands from where they are injected into a new victim with the next mosquito bite – the fatal vicious cycle of malaria is completed.
Effects of malaria
The destructive activity of the plasmodia in the red blood cells rapidly leads to anemia, violent attacks of fever and cramps. If left untreated, serious complications affecting the kidneys, spleen, lungs and brain often result in the death of the victim within a few days. Although malaria is regarded as curable under optimal medical conditions, the necessary expensive medications are often lacking, especially in the rural regions of Africa. Moreover, increasing numbers of Plasmodium strains are developing resistance towards the most commonly used drugs – which is why preventing new infections is seen as the best approach to combating malaria.
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