Nepal may be infamous for its dangerous peaks, but in its valleys lies a far greater threat to human life: contaminated water.
It is one of the world's poorest countries, and two-thirds of the population lives without toilets. Water pipes in major cities are old and crumbling — a situation made worse by the earthquake that devastated Kathmandu in April.
Diarrhea remains a major killer of Nepalese children, although the death rate was cut in half between 2000 and 2010. Much of the credit goes to a newly recruited corps of "lady health workers" who taught basic hygiene, such as the need to use latrines and wash hands afterward. Local clinics also began stocking packets of oral rehydration solution.
Still, dirty water is a chronic problem in Nepal, especially when sewage from one village washes downstream to foul the drinking water of others. Some charities try to help by drilling wells.
The Kathmandu earthquake was followed by dire predictions that a cholera epidemic would break out as soon as summer monsoons flooded crowded tent camps. Those fears stemmed from events in Haiti, where a huge earthquake in early 2010 was followed 10 months later by a cholera epidemic that has since sickened 700,000 Haitians and killed 9,000 of them.
But those predictions failed to take into account crucial differences between the countries. In 2010, Haiti had not had a case of cholera in decades, so no one in the population was immune. Cholera is endemic in Nepal, so many adults have survived mild cases in childhood and have immunity.
Haiti's epidemic, in fact, was blamed on United Nations peacekeepers from Nepal. It began in the Arbonite River near a spot into which raw sewage was leaking from the Nepalese encampment. The strain was identical to one widespreadin Nepal.
Monsoon season is ending in Nepal with no serious waterborne disease outbreaks — possibly because the United Nations and major relief agencies prepared for the worst, setting up safe water sources in the camps or trucking water in.
But epidemics may yet happen, experts say, particularly in hard-to-reach rural areas.