The list of priority research questions focus on how to make the best use of interventions that are available today, in order to make the most difference, and ultimately save as many children's lives as possible.

Nearly 2 million children die from diarrhoea every year. If childhood diarrhoea is not addressed urgently, the countries will fail to achieve the fourth Millennium Development Goal (MDG4) target of reducing child deaths by two-thirds by 2015.

Despite the persistently high burden of disease, research into childhood diarrhoea has been steadily decreasing since the 1980s. Funds available for research into diarrhoea are less than those available for research in other diseases that cause fewer deaths.

A lot is already known about effective treatments for diarrhoea. But critical knowledge is lacking on how to make sure the children who need it most get access to that treatment. WHO has led a process to identify which types of research are most needed and would have greatest impact on mortality. A paper published in the March edition of the journal PLoS Medicine describes in detail the process undertaken to arrive at the list of priority research questions.

The resulting top 20 per cent of priority research questions are mainly targeted at better understanding the barriers to implementation, effectiveness and optimization of the use of available interventions and programmes such as oral rehydration salts (ORS) and zinc, exclusive breastfeeding and the integrated management of childhood illness. However, very few donor agencies presently recognize the importance of these domains of health research.

The life-saving treatment for diarrhoea is simple: ORS and zinc tablets. ORS is essentially a pinch of salt and a handful of sugar mixed with clean water. The cost of treating a child with ORS and zinc is about 30 US cents.

Dr Olivier Fontaine, medical officer with WHO's Department of Child and Adolescent Health and Development and lead author of the PLoS Medicine article, said, "Having seen, first hand, the devastation that childhood diarrhoea can cause, and also the almost miraculous, life-saving power of ORS and zinc, I certainly hope that we'll receive the support we need to come up with answers to some of the key questions that remain."

Children in poor countries get diarrhoea on average four times per year. Each of these episodes can be life-threatening. ORS and zinc bring the risk of death down to almost zero. More than 50 million children's lives have been saved by ORS since its creation 25 years ago. The great challenge now is how to reach all children who are still suffering and dying from diarrhoea.

Funding available for health research globally was US$ 126 billion in 2003, but that money has not always been targeted at diseases which affect the greatest number. Research on diarrhoea received less than US$ 10 per disability adjusted life year (DALY), while conditions like diabetes type 2 - another serious condition- received US$ 102 per DALY.

Similar exercises have been conducted by WHO to identify priorities for research on other "neglected" childhood diseases, including acute respiratory infections, birth asphyxia, neonatal sepsis, and low birth weight. A meeting of major supporters of child health research is being convened by WHO at the end of March 2009 to: share the lists of research priorities identified for these topics; identify a subset of priority research issues to be addressed in order to achieve MDG4; and identify sources of support for the agreed research questions.