COLIFORM ENTERITIS OF COTTONTAIL RABBITS.

Yuill, Thomas M. (University of Wisconsin, Madison), and Robert P. Hanson. Coliform enteritis of cottontail rabbits. J. Bacteriol. 89:1-8. 1965.-Mortality from enteritis occurred among 78 penned adult cottontail rabbits (Sylvilagus floridanus) during severe winter weather, and in 9 juvenile rabbits held in captivity during the summer. This mortality was associated with high numbers of Escherichia coli throughout the intestinal tract. Grossly normal cottontails from the laboratory, from the outdoor penned colony, and from the wild had few E. coli, and these were usually restricted to the lower gut. It was possible to induce mortality of adult rabbits by holding them at -20 C for 2 to 14 days. The animals that died during exposure to low temperatures had signs of enteritis and high numbers of E. coli throughout the intestinal tract. It was possible to prolong the life of cottontails held at -20 C by antibiotic suppression of their intestinal E. coli. A marked slowing in the rate of passage of materials through the intestine ensued after exposure at -20 C. This phenomenon may have been important in the alteration of the distribution of the intestinal microflora. Limited infection by E. coli occurs in rabbits in the wild. Of 47 serum samples from grossly normal cottontails collected in the wild, 42 contained E. coli agglutinins. The rabbit's defenses are apparently sufficient to control this organism under all but extremely unfavorable circumstances. The age of the rabbit appeared to influence its susceptibility to enteritis. Juvenile rabbits experienced enteritis, tissue invasion, and death under conditions which did not produce any enteric changes in adults.