Malaria overview: Difference between revisions
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Although effective anti-malarial drugs are on the market, the disease remains a threat to people living in endemic areas who have no proper and prompt access to effective drugs. Access to pharmacies and health facilities, as well as drug costs, are major obstacles. [[Médecins Sans Frontières]] estimates that the cost of treating a malaria-infected person in an endemic country was between US$0.25 and $2.40 per dose in 2002.<ref name="msf">Medecins Sans Frontieres, "[http://www.msf.org/content/page.cfm?articleid=44247857-6A39-4D9C-8FA7E54299FF1D4D What is the Cost and Who Will Pay?]"</ref> | Although effective anti-malarial drugs are on the market, the disease remains a threat to people living in endemic areas who have no proper and prompt access to effective drugs. Access to pharmacies and health facilities, as well as drug costs, are major obstacles. [[Médecins Sans Frontières]] estimates that the cost of treating a malaria-infected person in an endemic country was between US $0.25 and $2.40 per dose in 2002.<ref name="msf">Medecins Sans Frontieres, "[http://www.msf.org/content/page.cfm?articleid=44247857-6A39-4D9C-8FA7E54299FF1D4D What is the Cost and Who Will Pay?]"</ref> | ||
==References== | ==References== | ||
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Revision as of 17:12, 4 January 2013
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Malaria Microchapters |
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Malaria overview On the Web |
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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.
Risk Factors
Common risk factors for malaria include sickle cell disease, G6PD deficiency, thalassemias and Duffy antigen.
Diagnosis
Symptoms
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.
Treatment
Medical Therapy
Active malaria infection with P. falciparum is a medical emergency requiring hospitalization. Infection with P. vivax, P. ovale or P. malariae can often be treated on an outpatient basis. Treatment of malaria involves supportive measures as well as specific antimalarial drugs. When properly treated, someone with malaria can expect a complete cure.[4]
Primary Prevention
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.
Secondary Prevention
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.
Cost-Effectiveness of Therapy
Although effective anti-malarial drugs are on the market, the disease remains a threat to people living in endemic areas who have no proper and prompt access to effective drugs. Access to pharmacies and health facilities, as well as drug costs, are major obstacles. Médecins Sans Frontières estimates that the cost of treating a malaria-infected person in an endemic country was between US $0.25 and $2.40 per dose in 2002.[5]
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.
- ↑ If I get malaria, will I have it for the rest of my life? CDC publication, Accessed 14 Nov 2006
- ↑ Medecins Sans Frontieres, "What is the Cost and Who Will Pay?"