Intestinal Lesions Caused by a Strain ofChlamydia Suisin Weanling Pigs Infected at 21 Days of Age

Abstract

Abstract. The objective of this study was to determine whether a strain of Chlamydia suis shown previously to be an intestinal pathogen in gnotobiotic piglets could cause diarrhea and intestinal lesions in young weanling pigs. Pigs from 2 sows were randomly assigned to 2 groups. Group 1 included 13 pigs that were weaned at 24 hours of age and then housed in isolator units and fed milk replacer and unmedicated starter ration. Group 2 included 8 pigs that nursed their respective sows, consumed unmedicated starter ration, and were weaned at 21 days of age. Ten pigs in group 1 and 6 pigs in group 2 were inoculated orally with 4 ϫ 10 8 inclusion-forming units of C. suis strain R27 at 21 days of age. Control pigs were inoculated with sham inoculum. The pigs were necropsied 5-14 days postinoculation (DPI). None of the Chlamydia-infected pigs developed diarrhea. Villus atrophy was seen histologically in sections of ileum from Chlamydia-infected pigs in both groups 5 and 7 days DPI. Lymphangitis and multiple lymphohistiocytic and neutrophilic aggregates were seen in the submucosa, tunica muscularis, and serosa of the distal jejunum, ileum, and colon from Chlamydia-infected pigs in both groups 5-14 DPI. Immunostaining of sections of distal jejunum, ileum, and colon from infected pigs revealed chlamydial antigen in intestinal epithelium and in foci of lymphangitis/inflammation. The results indicated that C. suis strain R27 can cause intestinal lesions in young weanling pigs, and the lesions are similar to those seen in gnotobiotic piglets. The results also indicated that strain R27 causes asymptomatic intestinal infections in young weanling pigs, at least under the conditions of this study.

Evidence for Chlamydia in Crohns Disease

“…These positive data are small in number; however, among the microbial agents known to induce a lymphangitis, there are few that localize to the intestine and induce granulomatous obstruction of lymphatics [5,6].…”

“…Experimental studies in which young pigs, calves, and nonhuman primates were inoculated with chlamydia have shown that the organisms cannot be demonstrated in the tissues after 12 weeks [5,18]. The chlamydia are known to persist in tissues in a form that cannot be readily demonstrated [19][20][21].…”

“…Most importantly, however, some penetrate the intestinal mucosa and damage lymphatics, as in the pig disease [4][5][6] and in calves [22,32,33]. Additional consideration needs to be given to the Chlamydia spp.…”

“…After oral inoculation, Chlamydia suis invade and damage villous epithelial cells, then induce inflammation in villous lamina propria, and finally enter and damage lymphatic endothelium, the latter accompanied by intra-and extralymphatic inflammation [5,6]. One consequence of this localized intestinal infection is the production of granulomas that obstruct mucosal, mucosal sub, muscularis, and serosal lymphatics [4,6].…”

A nested multiplex polymerase chain reaction assay for the differential identification of three zooanthroponotic chlamydial strains in porcine swab samples

“…22 Chlamydia suis, which is a close relative of Chlamydia trachomatis, has been found in semen and genital tracts of boars, sows, bulls, and bucks; the clinical signs of the infected animals varied from conjunctivitis, to enteritis, to pneumonia. 14,25 Although there is no evidence about the possibility of infection in human beings with C. suis, the emergence of removable tetracyclineresistant plasmids in C. suis suggests a potential threat for the food safety of human beings. 34 Although Ch.…”