ETYM Italian, contr. from malaaria bad air. Related to Malice, and Air.
Infectious parasitic disease of the tropics transmitted by mosquitoes, marked by periodic fever and an enlarged spleen. When a female mosquito of the Anopheles genus bites a human who has malaria, it takes in with the human blood one of four malaria protozoa of the genus Plasmodium. This matures within the insect and is then transferred when the mosquito bites a new victim. Malaria affects some 267 million people in 103 countries, claiming more than a million lives a year. Between 1.5 and 2 million children die from malaria and its consequences each year in sub-Saharan Africa alone.
Inside the human body the parasite settles first in the liver, then multiplies to attack the red blood cells. Within the red blood cells the parasites multiply, eventually causing the cells to rupture and other cells to become infected. The cell rupture tends to be synchronized, occurring every 2–3 days, when the symptoms of malaria become evident.
In Brazil a malaria epidemic broke out among new settlers in the Amazon region, with 287,000 cases 1983 and 500,000 cases 1988.
Quinine, the first drug used against malaria, has now been replaced by synthetics, such as chloroquine, used to prevent or treat the disease. However, chloroquine-resistant strains of the main malaria parasite, Plasmodium fulciparum, are spreading rapidly in many parts of the world. Tests on a vaccine were begun 1986 in the US.
An experimental vaccine has been developed by Colombian scientist Manuel Patarroyo. So far it has been tested on 20,000 people in South America; however, the World Health Organization (WHO) wants further independent trials to investigate its effectiveness. Spain has approved such trials; the British Medical Research Council refused permission for the trials to be carried out in the Gambia Dec 1991.
In 1993 research began into using chelating agents, which remove surplus iron from the blood, to treat malaria.
The malaria vaccine SPf66 was trialled in rural Tanzania 1994, where villagers will be bitten an average of 300 times a year by infected mosquitoes. It reduced the incidence of malaria by a third. In May 1995, the WHO were given the go ahead to make, develop, and distribute SPf66.
An infective disease caused by sporozoan parasites that are transmitted through the bite of an infected Anopheles mosquito; marked by paroxysms of chills and fever.