Effective and affordable interventions that provide the global population with access to safe drinking water and adequate sanitation are needed if water-borne diseases are ever to be controlled.
This is the conclusion of a WHO report entitled 'Safe Water, Better Health', released last week (26 June).
The report provides for the first time country-by-country estimates of disease caused by poor water quality, sanitation and hygiene.
It finds that children, particularly in developing countries, suffer a disproportionate share of the disease burden caused by unsafe drinking water and poor sanitation.
The WHO estimates that almost ten per cent of the global disease burden is caused by unsafe water and sanitation and that the economic return of investing in improved access to safe drinking water was ten-fold.
The WHO's findings echo a study by researchers from the University of Michigan, who published a paper on the challenges of achieving global sanitation coverage in the journal Environmental Science and Technology.
They analysed barriers to global sanitation coverage such as inadequate investment, water availability, poor or nonexistent policies, governance, poor resources and gender disparities, and looked at the impact on water resources of various sanitation technology choices.
The researchers found that water availability was not a huge barrier at a global scale. Appropriate technological innovation is most needed to provide adequate toilets for the world's population, especially in water-scarce areas.
Dave Watkins, a researcher at the University of Michigan and one of the authors of the report, told SciDev.Net that while universal safe drinking water and sanitation access seems achievable, their study shows that lack of financial resources is the greatest impediment to sanitation coverage.
"Just a fraction of a per cent of wealthy countries' gross domestic product would be sufficient to meet global funding needs," he says.
"[But] use of appropriate technology, and local capacity building to ensure project sustainability are also necessary. Missing one or more of these key ingredients can easily lead to failed projects, which discourages investment."
Watkins believes the social and economic benefits of improved water and sanitation are grossly underestimated, and this is a route for future research.