Malaria is an infectious disease transmitted by mosquitoes that affects humans and other animals caused by protozoan parasites (a group of unicellular microorganisms) belonging to the Plasmodium type. Malaria causes symptoms that usually include fever, tiredness, 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 treated properly, 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 goes away for months or years if the person does not have continuous exposure to malaria.
The disease is most often transmitted by an infected female Anopheles mosquito. The bite of the mosquito introduces parasites of mosquito saliva into the blood of a person. The parasites travel to the liver where they mature and reproduce. Five species of Plasmodium can infect and infect humans. Most deaths are caused by P. 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 microscopic examination of the blood by blood tests or rapid diagnostic tests based on antigens. Methods that use the polymerase chain reaction to detect parasite DNA have been developed, but are not widely used in areas where malaria is common due to its cost and complexity.
The risk of disease can be reduced by preventing mosquito bites by using mosquito nets and insect repellents, or by controlling mosquitoes such as spraying insecticides and draining standing water. Several medications are available to prevent malaria in travelers to areas where the disease is common. Occasional doses of the sulfadoxine / pyrimethamine combination are recommended in infants and after the first trimester of pregnancy in areas with high rates of malaria. Despite the need, there is no effective vaccine, although efforts are being made to develop it. The recommended treatment for malaria is a combination of antimalarial drugs that includes an artemisinin. The second drug can be mefloquine, lumefantrine or sulfadoxine / pyrimethamine. Quinine can be used along with doxycycline if artemisinin is not available. It is recommended that in areas where the disease is common, malaria should be confirmed if possible before starting treatment due to concerns about increasing drug resistance. The resistance between the parasites has been developed to several antimalarial drugs; For example, P. falciparum resistant to chloroquine has spread to most malarious areas, and artemisinin resistance has become a problem in parts of Southeast Asia.
The disease is widespread in 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 296 million cases of malaria worldwide that resulted in an estimated 731,000 deaths. Approximately 90% of the cases and deaths occurred in Africa. The rates of illness have decreased from 2000 to 2015 by 37%, but increased as of 2014, during which there were 198 million cases. Malaria is commonly associated with poverty and has a significant negative effect on economic development. In Africa, it is estimated that it will cause losses of US $ 12 billion per year due to the increase in health care costs, the loss of work capacity and the negative effects on tourism.
