In many of the poorest countries of the world, a mosquito's bite can be deadly. Malaria, a parasitic disease transmitted by mosquitoes, kills 3,000 African children every day--that's about a child every 10 seconds. But we know how to treat and prevent malaria. Effective drugs exist that cure malaria. Bednets and spraying prevent mosquito bites. Despite these proven methods, 300 to 500 million people still contract malaria each year.

Most of these people live in the warmer places of the world, in tropical and subtropical climates where malaria thrives. It is transmitted from person to person through the bite of a female Anopheles mosquito, which requires blood to nurture her eggs.

Many children who survive an episode of severe malaria may suffer from learning impairments or brain damage. Though some adults develop certain immunities to malaria during their lifetime, pregnant women and their unborn children are particularly vulnerable to malaria. It is thus a major cause of perinatal mortality, low birth weight and maternal anaemia.

There are four types of malaria which affects humans: Plasmodium vivax, P. malariae, P. ovale and P. falciparum. P. vivax and P. falciparum are the most common--falciparum being the most deadly type of malaria infection.

The malaria parasite enters the human host when an infected Anopheles mosquito takes blood. Inside the host, the parasite undergoes a series of changes as part of its complex life-cycle. Its various stages allow it to evade the immune system, infect the liver and red blood cells, and finally develop into a form that is able to infect a mosquito again when it bites an infected person. Inside the mosquito, the parasite matures until it reaches the sexual stage where it can again infect a human host when the mosquito takes her next blood meal, 10 to 14 or more days later.

Malaria symptoms usually appear about 9 to 14 days after the infectious mosquito bite. Typically, malaria produces fever, headache, vomiting and other flu-like symptoms. If drugs are not available for treatment or the parasites are resistant to them, the infection can progress rapidly to become life-threatening. Malaria can kill by infecting and destroying red blood cells (anaemia) and by clogging the capillaries that carry blood to the brain (cerebral malaria) or other vital organs.

Malaria, together with HIV/AIDS and TB, is one of the major public health challenges undermining development in the poorest countries in the world.

Today malaria parasites are developing high levels of resistance to one drug after another and many insecticides are no longer useful against mosquitoes transmitting the disease. Years of vaccine research have produced few hopeful candidates and although scientists are redoubling the search, an effective vaccine is at best years away. For this reason, using artemisinin-based combination therapies (ACTs) are the best way to combat malaria infections.