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Malaria
 

This model explores the nature of malaria, a dangerous disease that is caused by one-celled parasite. Press "Run" button to initiate the model. Press "Stop" to bring the animation to a halt, and press "Reset" to return the model to its initial state.

The life cycle of a plasmodium - the agent of malaria - is based on the alteration of two carriers. The ultimate carriers are the malarial mosquitoes and the temporary carriers are humans. When a malarial mosquito bites a human, plasmodium enters the human blood stream as a sporozoite from the mosquito's saliva. Traveling with the blood stream, the sporozoite goes through the entire human body and penetrates the liver cells. There, the tissue part of plasmodium development occurs. During this stage, cellular division by way of schizogonia takes place. As a result, each schizont produces from 1000 to 5000 tissue merozoites. They enter the blood stream and invade the erythrocytes, where the erythrocyte part of the malarial agent's development occurs. This stage ends with division too, but this time trophozoites are produced.

The capsules of erythrocytes are torn and the merozoites along with the toxic byproducts of their vital activities enter the blood stream. This is what causes the malarial sickness in humans. Merozoites infiltrate the erythrocytes once again. This cycle is repeated many times. Inside the erythrocytes, some of the trophozoites become sex cells that enter the blood plasma as gametocytes (immature sex specimens, both male and female.) Their further development is only possible in the body of a mosquito. During a mosquito bite, the gametocytes enter the mosquito's digestive tract, where they fertilize each other, forming an oocyst. In the oocyst, cellular division happens as well, and once again, and a huge quantity (up to 10000) of sporozoites is formed. The oocyst eventually bursts, and the sporozoites migrate into the mosquito's salivary glands, ready to infect humans once again.

 
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