Ferrets are VERY intelligent and learn things much quicker than they unlearn them, so it is important to treat your ferret well from day one otherwise it will always be protecting itself or hiding from you. The disease appears to strike all age groups, but is rarely reported in kits. Clinical signs include a profuse green, watery diarrhea which is rapidly dehydrating. Occasionally, affected animals may progress to coma and death within 48 hours. Death most commonly occurs in older animals with concurrent health problems, such as insulinoma or adrenal disease.
Vomiting does appear to be an associated sign seen right before the first green poop.
At this time there is NO safe place to buy or adopt a ferret, in my opinion. Shelters and breeders have been dealing with ECE for at least four years. This last year, pet distributors started becoming contaminated. Research closely whether the place you are getting your new ferret from reports any strange poops or grainy stools. If you find a clean place to get a ferret, read up on ECE at resources such as Ferret Central to be prepared.