Around the world half a million children die every year from diarrhoea - usually children under the age of two who get dehydrated.
One of the researchers behind the study is Eric Houpt from the University of Virginia.
“What is a nuisance, generally, in developed countries, can be fatal in developing countries” says Houpt.
Health experts have previously thought the disease had a huge variety of causes and was therefore near-impossible to treat, but new research published in UK medical journal The Lancet reveals six pathogens which seem responsible for nearly 90 percent of cases.
It is now much more likely that vaccines and antibiotics can be developed to significantly reduce the death toll.
“One of the problems for public health experts when it comes to diarrhoea historically has been that even with the absolute best studies you only know up to half of a problem.”
Initial results, published three years ago, suggested that 51.5 percent of cases were down to pathogens. Reserachers decided to reanalyse the same samples using new genetic testing techniques. That analysis was more accurate and sensitive and suggested that 89.3 percent of childhood diarrhoea cases were caused by pathogens. Six pathogens were responsible for almost 78 percent of cases.
Before this improved molecular diagnostic testing, the cause of the other cases had been a mystery.
New vaccines and antibiotics will be developed within the next ten years, Houpt says.
"My feeling is that vaccine developments and proper use of antibiotics can lead to a large decrease in childhood diarrhoea over the next 10 to 20 years."