Malaria is a protozoan disease proceeding cyclically with recurrent febrile seizures, and progressive anemia, enlargement of the liver and spleen.

Fig. 1. The development cycle of the pathogen malaria (scheme): 1 - output sporozoite of duct salivary glands of the mosquito and incorporate it into the cell of a human liver; 2-4 - preerythrocytic cycle; 5-11 - erythrocytic schizogony; 12 and 13 - the development of women's Gamanta; 14 and 15 - development of male Gamanta; 16 - education of microgames; 17 - fertilization; 18 - penetration zygote through the wall of the stomach of the mosquito; 19 and 20 - development of cysts; 21 - gap Mature cysts and out of sporozoites; 22 - sporozoites in the mosquito salivary gland; 23-27 - development subsequent fabric generations of the parasite in the liver cells (Plasmodium falciparum has not occurred).

Etiology. By malaria parasites are unicellular protozoa of the genus Plasmodium (Plasmodium). Human parasites four species of Plasmodium (Plasmodium vivax is the causative agent of three-day malaria; Plasmodium malariae - exciter four malaria; Plasmodium falciparum - the causative agent of tropical malaria Plasmodium ovale - the causative agent of malaria occurring but the type of three-day malaria. Malarial parasites do two cycles of development: gender (sporogony) in the body of the mosquito Anopheles and asexual (schizogony) in the body (Fig. 1).
Transmitted malaria healthy person by the bite of an infected mosquito, saliva, which in the human body penetrate sporozoites. Through the blood and lymph sporozoites reach parenchymal liver cells, where tissue (decreased) schizogony. In all forms of malaria tissue schizogony precedes the infected erythrocytes - preerythrocytic schizogony. Later in tropical malaria parasites are developing only in erythrocytes and other forms of malaria tissue schizogony continues simultaneously with the development of them in erythrocytes - parasiterna schizogony. At the end preretraitees of schizogony tissue merozoites invade the red blood cellsbecome schizonts, further development and division which leads to the formation of red blood cell merozoites. Red blood cells are destroyed, the released merozoites infect new cells, and the cycle resumes. Part of merozoites turns into gametocytes - male and female sexual stage parasites, which, once with blood in the stomach of the mosquito, give rise sporogonic development.

Fig. 1. Erythrocytic forms of Plasmodium man: I - Plasmodium vivax; II - Plasmodium malariae; III - Plasmodium falciparum; IV - Plasmodium ovale, 1 - a ring-shaped; 2 - schizonts; 3 - fissile schizonts; 4 - Marussia; 5-female gametocytes; 6 - male gametocytes. Fig. 2 and 3. Plasmodium vivax (Fig. 2-in a smear, Fig. 3-in the large drop). Fig. 4. Plasmodium malariae in a smear. Fig. 5. Plasmodium falciparum (left-in a smear, right in the large drop): 1 - rings; 2 - schizonts; 3 - fissile schizonts; 4 - Marussia; 5 - female gamonty; 6 - male gamonty; 7 - reticulocytes; 8 -platelets; 9 - cells.

The size and shape of the parasite at different stages of development, the quantity of generated merozoites and their size, color, and position of the pigment, the form of gametocytes, along with the specific changes observed in infected erythrocytes, are the features which distinguish one type of the causative agent from the other ( Fig. 1). The development of Plasmodium vivax, Plasmodium malariae and Plasmodium ovale is circulating in the blood, so in smears and thick drops of blood can discover all stages of the parasite (Fig. 2-4). In tropical malaria in the peripheral blood can be seen only rings and Mature gametocytes (Fig. 5)since the development of schizonts occurs in the capillaries of the internal organs. On the territory of the USSR met three species of Plasmodium malaria (Plasmodium vivax, Plasmodium malariae and Plasmodium falciparum. In persons who arrived from the countries of tropical Africa, in recent years, often reveals Plasmodium ovale.