Simple adult rabbit model for Vibrio cholerae and enterotoxigenic Escherichia coli diarrhea

We developed an adult rabbit model for enteric infection by Vibrio cholerae and enterotoxigenic Escherichia coli. The cecum of each animal was first ligated to prevent it from retaining fluid secreted by the small intestine. A temporary reversible obstruction (a slip knot tie) of the small bowel was introduced at the time of challenge and removed 2 h later. With this modification, we were able to elicit a massive and usually fatal cholera-like diarrhea in adult (3.5- to 6-lb [1.6- to 2.7-kb]) animals challenged with V. cholerae. Animals challenged with enterotoxigenic E. coli also developed diarrhea which was severe and watery but less explosive and less rapidly fatal than that produced by V. cholerae. The susceptibility of animals in this model to infection by V. cholerae was similar to the susceptibility of infant rabbits challenged intraintestinally. The death rate was almost 25% when 10(3) Vibrio cells were given and 90% or more when the dose was greater than or equal to 10(6) cells per animal. We designated this procedure the RITARD (for removable intestinal tie-adult rabbit diarrhea) model.