Unfortunately, things in Vietnam are getting worse, in the cholera department. ProMed released a story today about several tourists becoming infected with cholera, in Ho Chi Minh city and Hanoi. The story comes from a chinese newspaper (translated in english).
Both cases involved eating at some “roadside” food stands and contact with raw food and the now infamous shrimp paste.
For travelers in the area beginning to have diarrheal symptoms, hydration is the most important thing you can do. See more about how to treat diarrheal illness here.