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The Parasite: Malaria is caused by the Plasmodium parasite, which spreads by infecting two types of hosts: humans and female mosquitoes. The parasite's life cycle begins when mosquitoes pick them up in the "blood stage" during a blood meal. After 10-18 days, the parasites are found as sporozoites in the mosquito's salivary gland. The mosquito injects these sporozoites into a human when feeding and this starts a human infection. The cycle will continue when a female mosquito bites another human and contracts the parasite, once more. The mosquito, as a vector, does not suffer from any side effects while carrying the parasite. Four species of the Plasmodium parasite infect humans.
The Infection: In humans, the Plasmodium parasite grows and multiplies in the liver cells and later in red blood cells. Broods of these parasites grow inside the red blood cells and release "daughter parasites" that go on to invade other cells in a relentless 48-hour cycle. As this occurs, humans display a wide variety of symptoms. These include fever, chills, sweating, headaches and muscle pains — much like the symptoms of the common flu. In a classic and uncomplicated case of malaria, the attack lasts 6-10 hours and is divided into a cold (shivering) stage, a hot (fever) stage and a sweating stage. These attacks occur every 2 to 3 days throughout the duration of the infection.
But severe complications can include cerebral malaria (seizures, coma, neurologic abnormalities), anemia, kidney failure, cardiovascular collapse, pulmonary edema, and other life-threatening ailments. Severe malaria usually occurs in people who have compromised immune systems or whose immunity has decreased as a result of high malaria transmission rates. The incubation period for malaria is generally 7 to 30 days, after which the symptoms become apparent. Some dormant forms of malaria can cause symptoms several months or even years after the initial mosquito bite.
Treatment: Malaria should be treated as soon as possible and physicians can choose from a range of antimalarial drugs including chloroquine, sulfadoxine-pyrimethamine, mefloquine, atovaquone-proguanil, quinine, doxycycline and artemisin derivatives. The treatment for malaria depends largely on the species of Plasmodium parasite, the area where the infection was acquired and the health of the patient.
Prevention: In areas where malaria is endemic (tropical regions across Asia, South America and Africa), prevention is achieved by using personal protection measures against mosquitoes, such as treating bed nets with insecticide. Administering antimalarial drugs, particularly among vulnerable groups like pregnant women and children, can also help prevent infection. Travelers from non-endemic countries should take similar precautions when visiting areas that have a high transmission rate.
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Featured in Living With the Enemy, Episode 5 of MONSTERS INSIDE ME
Wednesday, August 6, 9 PM e/p
Killers? No. Users? You betcha. These parasites keep the party going for as long as possible. Highlighting malaria, the pork tapeworm and Toxoplasmosis.
 Download a wallpaper-sized malaria parasite picture.
 Visit the Monsters Inside Me video gallery.
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