More trees can reduce diarrhoeal disease in rural kids

When it comes to sanitation, trees may not be more important than toilets, but a study of 300,000 children in 35 nations has found that increasing tree cover in watersheds can reduce the burden of diarrhoeal disease, which has many causes, including waterborne pathogens.

Diarrhoeal disease is the second leading cause of death for children under the age of five. According to the World Health Organisation (WHO), 361,000 children die of diarrhoeal disease every year because of poor access to clean water, sanitation and hygiene.

A 30 per cent increase in upstream tree cover in rural watersheds would have a comparable effect to improved water sanitation, such as the addition of indoor plumbing or toilets, said the study published in the journal Nature Communications.

"This suggests that protecting watersheds, in the right circumstances, can double as a public health investment," said Brendan Fisher from the University of Vermont in the US. 

"This shows, very clearly, how 'natural infrastructure' can directly support human health and welfare," Fisher said.

The research is the first to use a massive new database that will enable "big data" approaches to study links between human health and the environment, globally.

"looking at all of these diverse households in all these different countries, we find the healthier your watershed upstream, the less likely your kids are to get this potentially fatal disease," Taylor Ricketts of Gund Institute for Environment, University of Vermont, added.

The findings suggest that forests and other natural systems can complement traditional water sanitation systems and help compensate for a lack of infrastructure, Diego Herrera from the Environmental Defense Fund, a US-based non-profit, added.

The researchers hope the findings will help governments and development agencies to improve the health and environment of children around the world.