Malaria is a life threatening blood disease caused by a parasite. Malaria is transmitted to humans by the Anopheles mosquito. it is caused by infection with the Plasmodium genus of the protozoan. There are more than several hundreds of these infectious parasites. It is known that there are five tpyes of malaria.
The first type of malaria are Plasmodium viva known as the milder form of the disease. It is generally not fatal but the only thing is that the parasite has a liver stage and can remain in the human body for years without causing any sickness. The second type of malaria is Plasmodium malariae, which has been known to stay in the blood of the infected person for several decades. The third type of malaria is Plasmodium ovale. If this type is to ever remain untreated there would be a risk that the liver stage would reactivate and cause relapses after very long periods without symptoms. The forth type of malaria is Plasmosium falciparum which is the most serious form of the disease. The fifth type of malaria is Plasmodium knowlesi which is known to cause malaria in animals such as monkeys but can also in most cases cause malaria in humans. It is important to keep in mind that the type of malaria you are diagnosed with is dependent upon the kind of parasite you are infected by.
Animals can get infected with malaria but human malaria cannot spread to animals, vise versa animal malaria cannot spread to humans. The way a human gets infected with the disease is when the parasite enters the blood stream and travels to the liver, where they multiply. When they re-emerge into the blood stream symptoms appear. By the time most symptoms show up, the parasites have reproduced very rapidly, clogging blood vessels and rupturing cells. Another way in which to explain this is that it all starts when a female mosquito harboring malaria feeds on human blood and transmits threadlike structures, called sporozoites, to the human. The sporozoites travel to the liver and multiply. They mature over two to four weeks without causing disease symptoms. The mature sporozoites, called merozoites, are released into the bloodstream, where they penetrate red blood cells and multiply and break down hemoglobin, which is essential for oxygen transport. The blood cells then degrade, and the merozoites escape and infect other blood cells. This induces bouts of fever, chills, sweating, and anemia in the infected individual. The infected red cells can obstruct blood vessels in the brain, which is called cerebral malaria or other vital organs, leading to the death of the patient. A few parasites form a sexual stage, which can be sucked up by another mosquito taking a blood meal, beginning a new transmission cycle. Two sexually active parasites meet in the mosquito's gut and produce a new generation. Only the female Anopheles mosquito can transmit malaria. This occurs when the mosquito bites an infected human; the malaria parasite in the blood is taken. About a week later that same infected mosquito takes its next blood meal. The plasmodium parasites mix with the mosquito’s saliva and are injected in to the host, which is the human being. It is also possible to spread malaria through contaminated needles or in blood transfusions. This is why all blood donors are screened for exposure to malaria.