Malaria death toll much greater than thought - strong link to bacterial infections found

Friday, 16 September 2011 09:45

Written by Gozde Zorlu

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Reducing the incidence of malaria could also drastically reduce the number of deaths from bacterial infections among children in Africa, a study has found.

"Children who are protected from malaria are less likely to catch bacterial infections. It therefore means that controlling malaria will give an additional benefit," Anthony Scott, the lead author and a researcher at the KEMRI-Wellcome Trust Research Programme, in Kenya, told SciDev.Net

Invasive bacterial diseases, such as pneumonia, meningitis and sepsis, are a major cause of illness and death among children in Africa, with mortality in Kenya as high as 22 per cent of those infected.

The study, published in The Lancet this month (7 September), found that children with a single copy of the sickle cell gene, which offers protection against malaria, are also protected against bacterial infections.

But they did not know why those children were protected — because of the gene itself or just the fact that those children did not get malaria.

So they looked at the number of cases admitted for each infection over an eight-year period at a district hospital in Kilifi, Kenya. The number of cases of malaria dropped almost by 90 per cent from 1999 to 2007, when malaria interventions were introduced to the area. The rate of hopital admissions for child bacteraemia — bacterial infections of the blood — also fell by 44 per cent during this time.

Among children with the sickle cell trait, the protection observed against bacteraemia disappeared as malaria also disappeared.

"The gene itself is not offering direct protection. This implies very strongly that infection with malaria makes children more susceptible to bacteraemia," said Thomas Williams, a co-author of the study from the UK's University of Oxford.

The researchers estimate that more than half of bacterial blood infections were associated with malaria and that invasive bacterial disease is six to seven times more likely in children with malaria.

"The association between malaria and bacterial infections has been known for a long time but the magnitude of the association is new," Keith Klugman, professor of global health at Emory University, United States, who was not involved in the study, told SciDev.Net.

Scott said: "We need to continue investing in interventions against malaria since the benefits go beyond just protecting children from malaria. It offers the additional benefit of reducing the general burden of disease in the community."

Link to article in The Lancet.

Reference: The Lancet doi:10.1016/S0140-6736(11)60888-X (2011).

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