There have been significant reductions in malaria transmission in endemic countries in Africa, but 57% of the population still lives in areas with a moderate or high risk for malaria transmission, researchers reported in The Lancet.
“Almost all of those (87%) in the two highest endemicity classes are living in just 10 countries,” Robert Snow, FMedSci, of the Malaria Public Health Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, said in a press release. “Of these, three — Guinea, Mali and Togo — are not part of the 10 countries that are the focus of the WHO Malaria Situation Room.”
Snow and colleagues evaluated data from a collection of community-based surveys of parasite prevalence covering 3,575,418 person observations from 44 malaria-endemic countries and territories in Africa since 1980. They used model-based geostatistics to estimate the proportion of children aged 2 to 10 years across Africa infected with different levels of Plasmodium falciparum in 2000, after the launch of the Roll Back Malaria Initiative, and a decade later in 2010.
They found substantial reductions in malaria transmission from 2000 to 2010: More than one-quarter of the population now lives in areas with a lower risk for infection. The number of people living in high-risk areas declined 16%, from 218.6 million to 183.5 million. However, the number of people living in moderate- to high-risk areas increased by 57%, from 178.6 million to 280.1 million.
However, the number of people living in areas of low-risk increased by 64%, from 78.2 million to 128.2 million. Four countries — Cape Verde, Eritrea, South Africa and Ethiopia — joined Swaziland, Djibouti and Mayotte as areas with endemic control.
“In a period of global economic recession, these results emphasize the need for continued support for malaria control, not only to sustain the gains that have been made, but also to accelerate the reduction in transmission intensity where it still remains high,” Snow said. “If investments in malaria are not sustained, hundreds of millions of Africans run the risk of rebound transmission, with catastrophic consequences.”
In an accompanying comment, Sir Brian Greenwood, FMedSci, professor of clinical tropical medicine at the London School of Hygiene and Tropical Medicine, and Kwadwo Koram, MD, PhD, associate professor at Noguchi Memorial Institute of Medical Research in Ghana, said the reductions in malaria transmission are encouraging but modest, and the gains are threatened by resistance to insecticides and potential of artemisinin-resistant malaria parasites.
“More could be done to improve malaria control in high-risk countries by increasing coverage with proven interventions such as insecticide-treated nets and chemoprevention,” they wrote. “However, a focus on elimination must no result in a reduction in support for development of new methods (drugs, insecticides, vaccines and new approaches to vector control), and improved delivery methods, which will be needed in large areas of sub-Saharan Africa before malaria transmission can be reduced to the level at which elimination becomes a credible prospect.”
For more information:
Greenwood B. Lancet. 2014;doi:10.1016/S0140-6736(14)60044-1.
Noor A. Lancet. 2014;doi:10.1016/S0140-6736(13)62566-0.
Disclosure: The researchers report no relevant financial disclosures.