(CNN) -- The vast majority of Africans have no access to a toilet, according to preliminary data from a World Health Organization report to be published later this year.
Chadians live in a crowded refugee camp in Cameroon. Refugees overwhelmingly lack proper sanitation.
The WHO-UNICEF Joint Monitoring Program for Water Supply and Sanitation said the data shows 62 percent of Africans and 2.6 billion people worldwide have no toilet at home "and thus are vulnerable to a range of health risks."
"Sanitation is a cornerstone of public health" said WHO's Director-General Dr. Margaret Chan. "Improved sanitation contributes enormously to human health and well-being, especially for girls and women.
"We know that simple, achievable interventions can reduce the risk of contracting diarrheal disease by a third."
The use of toilets and hand-washing with soap prevents the transfer of bacteria, viruses and parasites that might otherwise contaminate water supplies, soil and food.
"Nearly 40 percent of the world's population lacks access to toilets, and the dignity and safety that they provide," said Ann M. Veneman, UNICEF executive director.
"The absence of adequate sanitation has a serious impact on health and social development, especially for children."