Malaria Parasite

Pathogenic Agent

1. Using the microscope scientists have been able to study the structure of human blood, which was found to consist of transparent fluid and tiny red blood corpuscles swimming therein. It is these corpuscles that make blood red. In man's lungs they combine with oxygen which they carry to all the living cells of the body. In the last century, the red blood corpuscles ofpatients suffering from malaria were found to contain many Amoeba-like single-celled parasites.

2. Having penetrated a red blood corpuscle, the parasite grows at its expense. The full-grown parasite fills the entire corpuscle and then divides into several parts, not in two as the Amoeba does. Between 8 and 12 new parasites are formed, which burst the corpuscle and penetrate the blood stream along with the toxic excreta of the mother-parasite. The action of the toxic excreta on the human body causes a severe attack of fever. As for the young parasites, they get into healthy blood corpuscles, consume them, and burst them in a couple of days.

3. The attacks of fever coincide with the entry of malaria parasites into the blood stream and recur regularly, in some cases every twenty-four hours, in others - at intervals of two to three days. The number of parasites in the blood keeps increasing and a tremendous number of red blood corpuscles are destroyed. If the sick person does not receive timely medical attention he may die.

Transmitting Agent

4.Man gets malaria parasites from the malaria-carrying Mosquito. The Mosquito bites, and the parasites are injected into the man's organism with the saliva from the insect. After a certain period attacks of malaria begin. The Mosquito gets the parasites when it bites people suffering from malaria. Inside the Mosquito, the parasites multiply rapidly. In a few days, they fill the salivary glands of the Mosquito which becomes a malaria-carrier. Mosquito eggs are laid in shallow stagnant water. Therefore malaria is widespread in marshy places, especially where the climate is warm. Previously it was called "marsh fever".

Questions:

1. What does human blood consist of?

2. How do the malaria parasites grow?

3. Where do new parasites penetrate?

4. What causes a severe attack of fever?

5. What do the attacks of fever coincide with?

6. What happens if the sick person does not receive timely medical attention?

7. How does man get malaria parasites?

8. Why was malaria previously called “marsh fever”?

Date: 2015-12-13; view: 453; Нарушение авторских прав