Malaria is caused by the protozoan parasite Plasmodium, which is transmitted by Anopheles mosquitoes. There are four species of Plasmodium. Plasmodium falciparum (the most deadly, common in sub-Saharan Africa), Plasmodium vivax (debilitating but rarely fatal, common in Asia and South America), and the relatively scarce Plasmodium malariae and Plasmodium ovale.
Plasmodium parasites enter the human body in the saliva of a biting mosquito. The victim may not feel ill for some time, as the parasites first hide in the liver. After a few days, the parasites emerge to feed on the hemoglobin inside red blood cells. Malaria's characteristic fever and chills occur when the parasites emerge from the devoured cells to invade new ones, in the process poisoning the body with parasitic waste. As the parasites retreat into new cells to feed on hemoglobin, the malarial fever subsides, in a characteristic cycle of fever and chills.
Malaria can be prevented by avoiding the bites of infected Anopheles mosquitoes, and by taking prophylactic antimalarial medications. Malaria can be reduced locally by altering the landscape to reduce the survival of Anopheles mosquitoes (with insecticides or through environmental management). The effectiveness of these methods varies from locale to locale, depending on whether the local malarial mosquitoes and malaria parasites have evolved resistance to insecticides and drugs, and upon the biting and reproductive habits of the local malarial mosquitoes.
About sixty different species of Anopheles mosquitoes can transmit malaria. These malarial mosquitoes range throughout the temperate and tropical regions of the world. Their reproductive and biting behaviors and preferences vary widely.
Untreated, malaria leaves the infected weakened, anemic, and contagious to mosquitoes who can pass on the disease. In addition, vivax infections may relapse months and sometimes years later. Falciparum infections do not relapse, but can cause serious complications, some of the them deadly.
Prompt treatment can reduce the duration of malarial illness, and reduce the risk of complications from malaria.
Populations chronically exposed to falciparum malaria do acquire immunity to severe malaria disease. In these populations, most deaths occur among pregnant women and young children. Human populations in historically malarious areas also carry genetic mutations, such as sickle-cell gene and G6PD-deficiency, that reduce susceptibility to severe illness from malaria infection.
Today, ninety percent of deaths from malaria occur in Africa, where Plasmodium falciparum prevails. A disproportionate number of these infections occur in rural and remote areas where formal health care is scarce to nonexistent.
More quick facts:
CDC: http://www.cdc.gov/malaria/facts.htm
WHO: http://www.who.int/mediacentre/factsheets/fs094/en/index.html
Plasmodium parasites enter the human body in the saliva of a biting mosquito. The victim may not feel ill for some time, as the parasites first hide in the liver. After a few days, the parasites emerge to feed on the hemoglobin inside red blood cells. Malaria's characteristic fever and chills occur when the parasites emerge from the devoured cells to invade new ones, in the process poisoning the body with parasitic waste. As the parasites retreat into new cells to feed on hemoglobin, the malarial fever subsides, in a characteristic cycle of fever and chills.
Malaria can be prevented by avoiding the bites of infected Anopheles mosquitoes, and by taking prophylactic antimalarial medications. Malaria can be reduced locally by altering the landscape to reduce the survival of Anopheles mosquitoes (with insecticides or through environmental management). The effectiveness of these methods varies from locale to locale, depending on whether the local malarial mosquitoes and malaria parasites have evolved resistance to insecticides and drugs, and upon the biting and reproductive habits of the local malarial mosquitoes.
About sixty different species of Anopheles mosquitoes can transmit malaria. These malarial mosquitoes range throughout the temperate and tropical regions of the world. Their reproductive and biting behaviors and preferences vary widely.
Untreated, malaria leaves the infected weakened, anemic, and contagious to mosquitoes who can pass on the disease. In addition, vivax infections may relapse months and sometimes years later. Falciparum infections do not relapse, but can cause serious complications, some of the them deadly.
Prompt treatment can reduce the duration of malarial illness, and reduce the risk of complications from malaria.
Populations chronically exposed to falciparum malaria do acquire immunity to severe malaria disease. In these populations, most deaths occur among pregnant women and young children. Human populations in historically malarious areas also carry genetic mutations, such as sickle-cell gene and G6PD-deficiency, that reduce susceptibility to severe illness from malaria infection.
Today, ninety percent of deaths from malaria occur in Africa, where Plasmodium falciparum prevails. A disproportionate number of these infections occur in rural and remote areas where formal health care is scarce to nonexistent.
More quick facts:
CDC: http://www.cdc.gov/malaria/facts.htm
WHO: http://www.who.int/mediacentre/factsheets/fs094/en/index.html
