Submitted to: American Association of Veterinary Laboratory Diagnosticians
Publication Type: Abstract Only
Publication Acceptance Date: 6/28/1996
Publication Date: N/A
Technical Abstract: The objective of the study was to determine whether 2 chlamydial isolates recovered from nursery pigs with diarrhea are intestinal pathogens in gnotobiotic pigs. Chlamydial isolates R19 and R27 were propagated in eggs or Vero cells. Each piglet was fed 1 ml of inoculum containing 10**5 to 10**9 inclusion-forming units (IFU) of chlamydia mixed with sterile milk at 3-4 days of age. All principal piglets developed diarrhea 4-5 days post-infection (DPI). Group 2 piglets fed 10**9 IFU R27 became anorexic and were necropsied 4-7 DPI. Remaining group 2 principals (fed 10**6 IFU R27), together with sham-infected controls, were necropsied 4, 7, 10 DPI. Group 1 principals (fed 10**5 IFU R19), together with sham-infected controls, were necropsied 4, 7, 10, 14, and 18 DPI. Principals in both groups necropsied 4-14 DPI had watery colonic contents with flecks of undigested curd. Chlamydiae were reisolated from intestinal specimens through 14 DPI. Histologically, ileum from group 2 principals fed 10**9 IFU R27 was characterized by severe villus atrophy and necrosis of scattered villi; purulent exudate mixed with cellular debris was present in the lumen. Jejunum from these principals was characterized by villus atrophy and necrosis of villus tips. Ileum and distal jejunum from remaining group 2 principals (fed 10**6 IFU R27) and group 1 principals (fed 10**5 IFU R19) were characterized by mild to severe villus atrophy; this lesion was consistently seen in principals necropsied 7 and 10 DPI. Neutrophilic to neutrophilic-histiocytic lymphangitis and perilymphangitis were seen in the ileum and distal jejunum of all principals necropsied 7 and 10 DPI. The results of this study indicate that the chlamydial isolates R19 and R27 are intestinal pathogens in gnotobiotic pigs.