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Malaria is caused by the protozoan parasite Plasmodium (one of the Apicomplexa). The recognised species causing disease in man are P. falciparum (which alone accounts for 80% of the recognised cases and ~90% of the deaths) and P. vivax , but P. ovale , P. malariae , P. knowesli and P. semiovale are also known to cause malaria. The vector for human malarial parasite is the AnophelesAnopheles funestus Anopheles gambiae Anopheles moucheti Anopheles nili Anopheles ovengensis Anopheles is a genus of mosquito. Of the 400 Anopheles species, Anopheles gambiae is the best known, because of its role in the transmission of malaria parasites ( mosquitoThis article is about the insect; for the WWII aircraft see De Havilland Mosquito. See text. Mosquitoes are insects belonging to the order Diptera; genera include Anopheles Culex Psorophora Ochlerotatus Aedes Sabethes Wyeomyia Culiseta and Haemagoggus for.
Other mammals (bats, rodents, non-human primates) as well as birds and reptiles also suffer from malaria.
Symptoms of malaria include feverFever also known as pyrexia is a medical symptom which describes an increase in temperature to levels which are above normal (37 degrees Celsius 98. 6 degrees Fahrenheit). An adaptive mechanism, fever is the body's reaction to pathogens; it attempts to ki, shiveringShivering is a human bodily function in response to cold. When the core temperature of the body drops, the shivering reflex is triggered. Muscle groups around the vital organs begin to shake in small movements in an attempt to create warmth by expending e, arthralgiaArthralgia is a term used to describe pain in the joints. It is derived from the word algos meaning pain. Seen in brucella gonorrhoea. (joint pain), vomitingVomiting (or emesis is the forceful expulsion through the mouth of the contents of one's stomach. It is a mechanism for expelling ingested illness-causing food poisons. The act may be triggered by stimuli which might indicate the possibility of poisoning,, and convulsions. There may be the feeling of tingling in the skin, particularly with malaria caused by P. falciparum. Complications of malaria include comaFor other meanings of the word "coma", especially in astronomy, see coma (disambiguation In medicine, a coma is a profound state of unconsciousness, which may result from a variety of conditions including intoxication ( drug, alcohol or toxins), metabolic and death if untreated—young children are especially vulnerable.
Infected female Anopheles mosquitoes carry Plasmodium sporozoites in their salivary glands. If they bite a person, which they usually do starting at dusk and during the night, the sporozoites enter the person's body via the mosquito's saliva, migrate to the liver where they multiply within hepatic liver cells. They then turn into merozoite s which then enter red blood cells. There they multiply further, periodically breaking out of the red blood cells. The classical description of waves of fever coming every three or four days arises from simultaneous waves of merozoites breaking out of red blood cells during the same day.
The parasite is relatively protected from attack by the body's immune system because it stays inside liver and blood cells. However, circulating infected blood cells are killed in the spleen. To avoid this fate, the parasite produces certain surface proteins which infected blood cells express on their cell surface, causing the blood cells to stick to the walls of blood vessels. These surface proteins are highly variable and cannot serve as a reliable target for the immune system. The stickiness of the red blood cells is particularly pronounced in Plasmodium falciparum malaria and this is the main factor giving rise to hemorrhagic complications of malaria.
Some merozoites turn into male and female gametocyte s. If a mosquito bites the infected person and picks up gametocytes with the blood, fertilization occurs in the mosquito's gut, new sporozoites develop and travel to the mosquito's salivary gland, completing the cycle.
Pregnant women are especially attractive to the mosquitoes, and malaria in pregnant women is an important cause of still births and infant mortality.
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