Malaria is a life-threatening parasitic disease transmitted by mosquitoes. It was once thought that the disease came from fetid marshes, hence the name mal aria, (bad air). In 1880, scientists discovered the real cause of malaria: a one-cell parasite called plasmodium. Later they discovered that the parasite is transmitted from person to person through the bite of a female Anopheles mosquito, which requires blood to nurture her eggs.
There are 300-500 million new cases of malaria each year, with over 90% of cases occurring in sub-Saharan Africa. There are concerns that global warming will increase the number of people exposed to malaria, as will the emergence of anti-microbial resistant strains.
Malaria-endemic countries are some of the world's poorest. The proportion of the world's population at risk from malaria could increase from around 45% to 60% by the year 2050 and estimated numbers of annual deaths from malaria are predicted to rise from their present level of 2-3 million to anything between 3.5 and 5 million.
Malaria interferes with individuals' abilities to earn a living or attend school, and with children's mental and physical development. It also affects national economies by impeding trade, foreign investment and commerce. According to one estimate, if malaria had been eliminated 35 years ago, Africa's current annual gross domestic product would be US$400 billion, rather than US$300 billion - a difference five times greater than all development aid provided to Africa in 2002.
Subtropical countries or islands that have succeeded in eradicating malaria have subsequently seen substantially higher economic growth than their neighbours. Studies by the Commission on Macroeconomics and Health indicate that countries with intensive malaria have 33% less growth than countries without (regardless of geography or history).
Complete genetic maps for the three stages in the malaria life cycle - the human, the mosquito, and the parasite - have recently been completed. This information could help efforts to eradicate malaria. A number of public private partnerships have been developed to undertake research and development into new products because the market for these products is likely to be limited. More than 1 200 new drugs were registered between 1975 and 1996 but only three were anti-malarials.