










Malaria is a vector-borne infectious disease caused by protozoan parasites. It is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa. Each year, it causes disease in approximately 515 million people and kills between one and three million people, the majority of whom are young children in Sub-Saharan Africa.[1] Malaria is commonly associated with poverty, but is also a cause of poverty and a major hindrance to economic development.
Malaria is one of the most common infectious diseases and an enormous public health problem. The disease is caused by protozoan parasites of the genus Plasmodium. Only four types of the plasmodium parasite can infect humans; the most serious forms of the disease are caused by Plasmodium falciparum and Plasmodium vivax, but other related species (Plasmodium ovale, Plasmodium malariae) can also affect humans. This group of human-pathogenic Plasmodium species is usually referred to as malaria parasites.
Malaria parasites are transmitted by female Anopheles mosquitoes. The parasites multiply within red blood cells, causing symptoms that include symptoms of anemia (light headedness, shortness of breath, tachycardia etc.), as well as other general symptoms such as fever, chills, nausea, flu-like illness, and in severe cases, coma and death. Malaria transmission can be reduced by preventing mosquito bites with mosquito nets and insect repellents, or by mosquito control measures such as spraying insecticides inside houses and draining standing water where mosquitoes lay their eggs.
Although some are under development, no vaccine is currently available for malaria; preventative drugs must be taken continuously to reduce the risk of infection. These prophylactic drug treatments are often too expensive for most people living in endemic areas. Most adults from endemic areas have a degree of long-term recurrent infection and also of partial resistance; the resistance reduces with time and such adults may become susceptible to severe malaria if they have spent a significant amount of time in non-endemic areas. They are strongly recommended to take full precautions if they return to an endemic area. Malaria infections are treated through the use of antimalarial drugs, such as quinine or artemisinin derivatives, although drug resistance is increasingly common.
P. Vivax
Recognizable descriptions of malaria were recorded in Chinese, Indian, Egyptian and Mesopotamian texts as early as 5,000 years ago. Evidence from human DNA sequences shows the effects of malaria to be far older still, influencing human evolution across tens of thousands of years. It is no exaggeration to say that malaria has played a crucial role in human history, determining the fates of armies and empires. Malaria brought down Alexander the Great and saved Rome from Attila's hordes. Dubbed the 'King of Diseases' in the Vedas, its modern name comes from the Italian peninsula, where mal'aria or 'bad air' was thought to cause the debilitating paroxysmal tertian or quartan (three- or four-day) fevers and febrile deaths that ravaged the populace every year for millennia.
We now know that the infectious agent of malaria is not fetid swamp gas but an apicomplexan protist of the genus Plasmodium whose complex life cycle shuttles between human and mosquito hosts without any free-living stages. Four species of the parasite are known to commonly cause malaria in humans: P. falciparum, P. malariae, P. ovale, and P. vivax. Of the four, P. falciparum is the most deadly; vivax malaria was known historically as 'benign tertian' fever. However, vivax malaria is 'benign' only in that the misery the disease causes rarely ends in death. In fact P. vivax has several characteristics which make it a compelling object of study: