etiology of swine dysentery. II. Effect of a known microbial flora, weaning and diet on disease production in gnotobiotic and conventional swine

Germ-free and conventional swine were used to study the influence of a milk diet on the development of swine dysentery in germ-free swine; the effect of a known microbial flora in gnotobiotic swine followed by conventionalization and weaning to a corn-soybean ration; and the effect of an oral inoculation of spirochete B-78 on conventional swine. Typical signs and lesions of swine dysentery were produced in germ-free swine on the milk diet when inoculated with colonic scrapings from pigs with experimental swine dysentery. Dysentery did not occur, however, in gnotobiotic swine when they were inoculated orally with Escherichia coli, lactobacillus, Vibrio coli, and clostridium in combination with the spirochete B-78, neither did it occur after the conventionalization and weaning of these animals to a corn-soybean ration. Signs and lesions of dysentery, however, developed in conventional swine after oral inoculation of the spirochete (B-78). Swine dysentery is probably a mixed infection caused by the interaction of two or more microbial agents, some of which apparently compose part of the normal intestinal flora.