The UN estimates that 2.5 billion people are at risk of disease from poor sanitation, and that it claims the lives of 1.5 million children under the age of five every year. Diarrhoea, a major cause of child mortality in many countries around the world, is a particular focus of today’s campaign in which more than 120 million children in 70 countries across five continents are expected to take part.

Despite being singled out in the Millennium Development Goals sanitation is, perhaps unsurprisingly, an unpopular subject which has been termed the “silent crisis”. However in 2006 the BBC World Service Trust tackled the issues creatively and with measurable success as part of a wider initiative on child and maternal health in Cambodia:

In this creative Public Service Announcement (PSA) spot a group of enthusiastic school children deliver an important message about how to avoid diarrhoea through handwashing – in song.

Quantitative survey research carried out after the BBC World Service Trust’s mass media campaigns revealed that the prevalence of those reporting a child in their care with diarrhoea in the last month decreased from 17% to 13%, and that the number of people who said they washed their hands to avoid diarrhoea increased from 10% to 25%.

Elsewhere online, legendary cricketer Sachin Tendulkar heads the campaign in India, the BBC has the story plus more on handwashing at Unicef’s YouTube channel.