Malaria cases could have doubled

The number of cases of malaria may be double that previously estimated, a team of researchers has found.

A team of scientists, led by Robert Snow, based at the Wellcome Trust Research Laboratories in Kenya found that over half a billion people could be infected with the killer disease.

The research, which has been published in 'Nature', estimated that there were around 515 million clinical cases of malaria in 2002, although the actual figure could be between 300 and 660 million. The study also found that the figures dramatically rose in areas outside Africa, where the new figures were at least three times as high as those previously estimated by the World Health Organisation (WHO).

Malaria is caused by a mosquito-borne parasite and it is thought to be one of the world's biggest killers.

The new study, which has been published in Nature, used a computer model to construct a detailed world map to demonstrate how many people are likely to be experiencing malaria symptoms.

The team divided the world into regions where the disease is present, excluding areas above a certain altitude, where the parasite would be less able to survive, and extremely built-up areas where there was less clean water in which the mosquitoes could breed.

The search was further refined by the addition of population density estimates, the risk of becoming infected from a mosquito bite and medical reports on the likelihood of an infection developing into full-blown fever and other symptoms.

The report has been published as a global effort to tackle malaria is increasing. The Global Fund to Fight AIDS, Tuberculosis and Malaria, which co-ordinates government and private funding, has put £3.1 billion into researching these diseases since it was established in 2002.

However, public health advisors and advocates have said that more money is needed, mainly because it has already known how to treat malaria, through the use of measures such as insecticide-treated bed nets and drugs.

Experts at the WHO have confirmed that they will be working with Mr Snow's team to refine their own estimates of malaria infection. Eline Korenromp, from the WHO's malaria-monitoring unit in Geneva, Switzerland, said that the organisation's latest figures, due to be published later this year, are between 350 and 500 million and largely overlap with the findings of Mr Snow's team.

(KMcA/SP)