Just as important, after 35 years of work, researchers in Bangladesh and elsewhere have developed an effective cholera vaccine. It has been accepted by the W.H.O. and stockpiled for epidemics like the one that struck Haiti in 2010. Soon, there may be enough to begin routine vaccination in countries where the disease has a permanent foothold.

Merely creating that stockpile — even of a few million doses — profoundly improved the way the world fought cholera, Dr. Margaret Chan, secretary general of the W.H.O., said last year. Ready access to the vaccine has made countries less tempted to cover up outbreaks to protect tourism, she said.

That has sped up emergency responses and attracted more vaccine makers, lowering costs. “More cholera vaccines have been deployed over the last two years than in the previous 15 years combined,” Dr. Chan said.

A Revolution in Recovery

The treatment advances relied heavily on research and testing done at the International Center for Diarrheal Disease Research, known as the ICDDR,B, in Dhaka.