Reproduction of proliferative enteritis in hamsters with a pure culture of porcine ileal symbiont intracellularis.

Hamsters, three weeks old, were inoculated orally with suspensions of intracellular bacteria, grown in tissue culture cells, IEC-18, rat enterocytes. Cells had been infected with suspensions of intracellular bacteria derived from the lesions of proliferative haemorrhagic enteropathy occurring naturally in two pigs 916/91 and 1482/89. Infected cell lines containing each separate strain, 916/91 and 1482/89, were passaged one, two or five times and pure cultures of intracellular bacteria, identified as ileal symbiont intracellularis by immunological means, were collected from the cells and used as inocula. Ten of sixteen hamsters dosed with 916/91 passaged one or five times, developed lesions of proliferative enteritis evident as necropsy three weeks after inoculation. Hamsters inoculated with 1482/89 passaged twice and stored frozen, or IEC-18 cells alone or those left uninoculated, failed to develop lesions of proliferative enteritis. Campylobacter jejuni infection occurred throughout, in all groups. Marked hyperplasia of ileal enterocytes, associated with numerous intracellular curved bacteria was invariably detected in experimentally affected hamsters. Immunofluorescence reactions with specific antibodies indicated that these intracellular bacteria were also ileal symbiont intracellularis. The results suggested that proliferative enteritis could be reproduced in hamsters with a pure culture of an agent derived from pigs. We concluded that the reproduction of the disease with our inocula containing a single agent clarifies the aetiology of proliferative enteritis in both hamsters and pigs.