The number of deaths that could be prevented by basic hygiene measures is far greater than was thought.

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[GENEVA] Diarrhoea kills three times more over-five-year-olds in Africa and South-East Asia than previously thought, new research finds.

Some 1.15 million over-fives — thought to be mostly adolescents and the elderly — are dying in these regions each year from diarrhoeal diseases, according to the research, commissioned by the WHO. Until now the death toll estimate for these regions came to 380,000.

Preliminary results from the study — which has yet to be published — were presented at this week's meeting of the Foodborne Disease Burden Epidemiology Reference Group (FERG) (29 October) in Switzerland.

"These estimates highlight the significant burden of diarrhoeal diseases in adolescents and adults in the developing world," said Martyn Kirk, chair of the FERG Enteric Diseases Task Force, who presented the results.

For the study, Christa Fischer-Walker and Robert Black from Johns Hopkins School of Public Health in the US searched 25,000 journal articles for information on diarrhoea in the over-fives. Only six of the articles contained reliable figures on diarrhoeal deaths in developing countries for this age group (compared to hundreds for younger children) — and there was no data for China, Latin America, the Middle East or South Asia.

The new estimate is on a par with the global annual death toll for malaria. It is also equivalent to nearly one-third of all HIV deaths and to almost half the number of global deaths from tuberculosis, says Claudia Stein, medical officer of the WHO's Department of Food Safety and Zoonoses.

"What makes the tragedy even greater is that many of these diseases are clearly preventable," said Jørgen Schlundt, director of FOS. Schlundt calls for policymakers to be alerted to cheap strategies known to prevent diarrhoea.

Improvements in food safety, sanitation and hygiene are critical, says Kirk. He told the meeting that nearly half (48.9 per cent) of diarrhoeal deaths in the developing world are caused by the bacteria Enterotoxigenic Escherichia coli and Vibrio cholerae, both of which are associated with poor sanitation and are common in resource-poor countries.

Stein says major gaps remain in scientists' understanding of diarrhoeal deaths. Research focusing on older people attracts little funding, as a result of which the problem has never been thoroughly assessed in this group.

But it is expected that some of these gaps will be filled next year, when results emerge from studies in China and India. The FERG is also planning country-level studies across the world, the results of which should begin to emerge in 2010.