Malaria overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Malaria is a vector-borne infectious disease caused by protozoan parasites. 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. The most serious forms of the disease are caused by Plasmodium falciparum and Plasmodium vivax, but other related species (Plasmodium ovale, Plasmodium malariae, and sometimes Plasmodium knowlesi) can also infect humans. This group of human-pathogenic Plasmodium species is usually referred to as malaria parasites.
Historical Perspective
Malaria has infected humans for over 50,000 years, and may have been a human pathogen for the entire history of our species.[1] Indeed, close relatives of the human malaria parasites remain common in chimpanzees, our closest relatives.[2] References to the unique periodic fevers of malaria are found throughout recorded history, beginning in 2700 BC in China.[3] The term malaria originates from Medieval Italian: mala aria — "bad air"; and the disease was formerly called ague or marsh fever due to its association with swamps.
Pathophysiology
Malaria in humans develops via two phases: an exoerythrocytic (hepatic) and an erythrocytic phase. When an infected mosquito pierces a person's skin to take a blood meal, sporozoites in the mosquito's saliva enter the bloodstream and migrate to the liver.
Causes
Malaria is a vector-borne infectious disease caused by protozoan parasites. Malaria is commonly associated with poverty, but is also a cause of poverty and a major hindrance to economic development.
Epidemiology and Demographics
It is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa. Each year, it causes disease in approximately 650 million people and kills between one and three million, most of them young children in Sub-Saharan Africa.
References
- ↑ Joy D, Feng X, Mu J; et al. (2003). "Early origin and recent expansion of Plasmodium falciparum". Science. 300 (5617): 318–21. PMID 12690197.
- ↑ Escalante A, Freeland D, Collins W, Lal A (1998). "The evolution of primate malaria parasites based on the gene encoding cytochrome b from the linear mitochondrial genome". Proc Natl Acad Sci U S A. 95 (14): 8124–9. PMID 9653151.
- ↑ Cox F (2002). "History of human parasitology". Clin Microbiol Rev. 15 (4): 595–612. PMID 12364371.