Factbox: Malaria: the mosquito-borne killer

(Reuters) - Here are some facts about malaria:

-- Malaria is a parasitic infection transmitted by mosquitoes.

-- About 40 percent of the world's population is at risk of malaria, with about 243 million cases every year. Most at risk are those living in the world's poorest countries.

-- Most of the nearly 863,000 annual deaths from malaria are among children in Africa under the age of five.

-- More than 90 percent of cases are caused by Plasmodium falciparum, the most destructive malaria parasite that is found mainly in Africa.

-- The disease can damage the nervous system, kidneys and liver, and severe cases can quickly lead to death.

-- The disease accounts for around 40 percent of public health spending in sub-Saharan Africa, and malaria-related illnesses and deaths are estimated to cost Africa's economy $12 billion a year.

-- It would cost an estimated $4.2 billion a year to fund the fight against malaria fully.

SOURCES: Reuters, World Health Organization and the Malaria Vaccine Initiative