Production of enteritis in calves by the oral inoculation of pure cultures of Campylobacter fetus subspecies intestinalis.

Pure cultures of an isolate of Campylobacter fetus subspecies intestinalis obtained from the congested small intestinal mucosa of a two-week-old calf were used to infect three milk-fed calves and three ruminating calves in two separate controlled experiments. Inoculated animals all developed clinical signs which included fever (to 40 degrees C) and diarrhoea with excess clear mucus containing occasional spots of blood. C fetus subspecies intestinalis was isolated from the faeces of all infected animals in the two experiments but not from those of the five control animals. Changes in the enteric tract were most marked in the ileum which was thickened and mildly inflamed with accumulations of lymphoid cells and crypts filled with inflammatory cells in all six infected animals. The mesenteric lymph nodes were pale and enlarged. C fetus subspecies intestinalis was recovered from the jejunum, ileum, caecum and colon of the infected animals and less frequently from the abomasum, mesenteric lymph nodes, liver and gall bladder. It was never isolated from the control animals. Antibody to the inocular strain of C fetus subspecies intestinalis was demonstrated, at titres of at least 1 in 320, in the serum of all inoculated animals and was absent from all the control sera. The findings were considered to indicate that C fetus subspecies intestinalis caused the syndrome described above and that the syndrome produced differed only in minor details from that produced in calves by infection with C jejuni.