MALARIA

Protozoa are unicellular eukaryotes and in most cases considerably larger than bacteria, but still of microscopic dimensions. The phylum protozoa comprises mainly four groups namely sarcodina, Mastigephora, ciliophora and sporozoa. The causative organism of Malaria (plasmodium) is included under the group sporozoa.

The name malaria expresses the association of this disease in bad air itself. Female mosquitoes of the genus Anapheles transmit this protozoan parasite.

Malaria is characterized by intermittent fever with anemia due to destruction of red blood cells. Four species of plasmodium cause Malaria. Plasmodium vivax causes most widely distributed malarial fever. Fever occurs after every two days. Plasmodium falciparum causes most severe type of disease common in tropics. Fever occurs for every two days or less. Plasmodium malariae is much less common and is mainly found in subtropical and tempereate zones. Fever reoccurs at three days interval. Plasmodium ovale predominant in west Africa and rare in other areas.

Infection: The pathogen completes its life cycle in man and female anopheles mosquito.

Life cycle in man : The pathogen enters human blood stream in the form of small spindle shaped sporozoites when the female Anapheles mosquito in which the parasite has completed its sexual cycle. From the blood the sporozoites enter liver where they develop into large multicellular shizonts. About 5 to 10 days after the infection shizonts breakdown into many merozoites and these merozoites enter blood stream which infect red blood corpuscles. Within the RBC they form trophozoites which are released after the lysis of red blood corpuscles and reinfect new red blood cells. Thus erythrocytic cycle reoccurs at usually 48 hours cycle. Some of the merozoites which invade RBCs become either male or female gametocytes.

Life cycle in mosquito : When these gametocytes sucked by mosquitoes, those gametocytes fuse to form zygote in the intestine of mosquito an it develop into oocyst. Mature oocysts rupture and release sporozoites which make their way to infect salivary glands and then ready to initiate a fresh human infection.

Lab diagnosis : T he diagnostic test for Malaria include straining blood smears with Giemsas strain. Plasmodium can be recognized in stained blood film.

Treatment : Chloroquine is the best drug for the treatment.

Prophylaxis : This include elimination of mosquito breeding places and personal protection against mosquito bites