Malaria is a mosquito-borne infectious disease affecting humans and other animals
caused by parasitic protozoans (a
group of single-celledmicroorganisms) belonging to the Plasmodium type.
Malaria
causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases it can cause yellow skin, seizures, coma,
or death. Symptoms usually begin ten to fifteen days after being
bitten. If not properly treated, people may have recurrences of the disease
months later In those who have
recently survived an infection, reinfection usually causes milder symptoms.
This partial resistance disappears over months to years if the
person has no continuing exposure to malaria
The disease is most commonly transmitted by an infected
femaleAnopheles mosquito.
The mosquito bite introduces the parasites from
the mosquito's saliva into a
person's blood. The parasites travel to the liver
where they mature and reproduce. Five species of Plasmodium can infect and be spread by humans. Most deaths are caused byP. falciparum because P. vivax, P. ovale, and P. malariae generally cause a milder form of
malaria.
The species P. knowlesi rarely causes disease in humans. Malaria is typically diagnosed by the microscopic examination of
blood using blood films, or with antigen-based rapid diagnostic tests. Methods that use the polymerase chain reaction to detect the parasite's DNA have been developed, but are not
widely used in areas where malaria is common due to their cost and complexity.
The risk of disease can be reduced by preventing mosquito
bites through the use of mosquito nets and insect repellents, or with mosquito control measures
such as spraying insecticides and
draining standing water. Several medications are available to prevent malaria in travellers to areas where the
disease is common.
Occasional
doses of the combination medication sulfadoxine/pyrimethamine are recommended in infants and
after the first trimester of pregnancy in
areas with high rates of malaria. Despite a need, no effective vaccineexists, although efforts to develop one are ongoing.
The
recommended treatment for malaria is a combination of antimalarial medications that includes an artemisinin The
second medication may be either mefloquine, lumefantrine, or sulfadoxine/pyrimethamine Quinine along
with doxycyclinemay be
used if an artemisinin is not available.
It is
recommended that in areas where the disease is common, malaria is confirmed if
possible before treatment is started due to concerns of increasing drug resistance. Resistance among the
parasites has developed to several antimalarial medications; for example, chloroquine-resistant P. falciparum has spread to most malarial areas, and
resistance to artemisinin has become a problem in some parts of Southeast Asia.
The
disease is widespread in the tropical and subtropical regions
that exist in a broad band around the equator. This
includes much of Sub-Saharan Africa, Asia, and Latin America. In 2015, there were 214 million cases of
malaria worldwide resulting in an estimated 438,000 deaths, 90% of which
occurred in Africa. Rates of
disease have decreased from 2000 to 2015 by 37%, but increased from 2014 during which
there were 198 million cases. Malaria is commonly
associated with poverty and has a major negative effect on economic development. In Africa, it is estimated to
result in losses of US$12 billion a year due to increased healthcare costs,
lost ability to work, and negative effects on tourism.

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