New York Times, October 27, 2014
Researchers supported by the Bill & Melinda Gates Foundation, the International Initiative for Impact Evaluation and the London School of Hygiene & Tropical Medicine picked 100 villages in the Odisha state of India with a total of 51,000 inhabitants and built large numbers of latrines in half of them. They focused on reaching households with young children.
After more than two years, they found that the health of children in the villages with latrines had not improved. Diarrhea rates were virtually the same. So was the prevalence of parasitic worms that can cause stunting and mental impairment. Children in villages with latrines had not grown faster than children in those without, nor had they even gained more weight.
The authors, whose work was published by The Lancet this month, could not fully explain the failure of latrine building to do more good. Some households did not use the latrines consistently, they said–compliance was particularly bad among men and children. Many users who had to clean themselves with their hands did not wash their hands with soap afterward. And animal feces lying around may have caused problems.