Malaria
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Malaria is an infectious disease caused by a parasite that is transmitted by the bite of infected mosquitoes of the Anopheles genus. There are three groups of mosquitos, Aedes, Anopheles, and Culex. While all three can carry diseases, the Anopheles mosquito is the only mosquito that transmits malaria to humans. The disease results from the multiplication of Plasmodium parasites within red blood cells. The malaria parasite is about four picometers in total size. The parasite is extremely small and can only be seen with a microscope. When looked at under a microscope, the malaria parasite is seen as being purple. A female Anopheles mosquito carrying malaria-causing parasites feeds on a human and injects the parasites in the form of sporozoites into the bloodstream. The lifecycle is a long and complicated cycle and the malaria parasite can live up to a two or three weeks. The sporozoites travel to the liver and invade liver cells. Over five to sixteen days, the sporozoites grow, divide, and produce tens of thousands of haploid forms, called merozoites, per liver cell. The merozoites exit the liver cells and re-enter the bloodstream, beginning a cycle of invasion of red blood cells, asexual replication, and release of newly formed merozoites from the red blood cells repeatedly over one to three days. Instead of replicating, the merozoites in these cells develop into sexual forms of the parasite, called male and female gametocytes that circulate in the bloodstream. When a mosquito bites an infected human, it ingests the gametocytes. In the mosquito gut, the infected human blood cells burst, releasing the gametocytes, which develop further into mature sex cells called gametes. Male and female gametes fuse to form diploid zygotes, which develop into actively moving ookinetes that burrow into the mosquito midgut wall and form oocysts. Growth and division of each oocyst produces thousands of active haploid forms called sporozoites. After eight to fifteen days the oocysts bursts, releasing sporozoites into the body cavity of the mosquito, from which they travel to and invade the mosquito salivary glands. The cycle of human infection re-starts when the mosquito takes a blood meal, injecting the sporozoites from its salivary glands into the human bloodstream. The Malaria parasite needs a group of enzymes called protein kinases to survive in the human blood stream. This is the main food requirement that the malaria parasite needs to survive.
There are many symptoms that malaria causes. These include a fever, chills, headache, sweats, fatigue, dry cough, back pain, an enlarged spleen, nausea and vomiting. In rare cases, malaria can lead to impaired function of the brain or spinal cord, seizures, or loss of consciousness. In regions where malaria is present, people who get infected many times may have the disease, but have few or no symptoms. The severity of the malaria symptoms can vary depending on the persons general health, the type of malaria,