Diarrhoea in growing-finishing pigs is a common problem of commercial pig farms. Among many causative factors, porcine circovirus type 2 (PCV2) is one considered an important pathogen in modern pig production. The aim of the study was to verify if PCV2 was responsible for antibiotic non-responsive diarrhoea and wasting in pigs. A total of 13 dead pigs aged between 12 and 15 weeks from three Polish farms with persistent herd symptoms suggestive of PCV2 infection were provided for evaluation. Sections of lymph nodes and intestines were analysed by in situ hybridization (ISH) for PCV2 and histopathological examination. Faeces and intestinal scrapings were tested for Lawsonia intracellularis and Brachyspira hyodysenteriae by real-time PCR and for parasitic infection by flotation and decantation. ISH and histopathological examination showed that all pigs were PCV2 systemic disease negative. Swine dysentery was confirmed by real-time PCR on two farms, and proliferative enteropathy on one farm. In histological examinations, erosions of the caecal and colonic mucosa were found, together with cysts and trophozoites of Balantidium coli. The protozoa were present in the intestinal lumen and mucosa. B. coli cysts were identified in faeces from all examined pigs. These results suggest that monitoring of B. coli infections should be an additional measure of control and prevention of gastrointestinal tract disorders in modern swine husbandry.

Reduced prevalence of diarrhea and mortality has been reported after dietary supplementation with zinc compounds in swine with naturally acquired colibacillosis and those challenge-exposed with Serpulina hyodysenteriae; however, the usefulness of this approach for control of enteric diseases of swine remains to be determined. To examine the effect of dietary zinc-containing compounds on the colonization and development of cecal lesions associated with S hyodysenteriae infection, a defined diet alone or with added ZnO, ZnSO4, or Zn-methionine complex to a final concentration of approximately 6,000 mg of Zn2+/kg of complete feed was fed ad libitum to 156 female mice (strain C3H/HeN) for 10 days prior to oral inoculation either with S hyodysenteriae or sterile trypticase soy broth. Rations were continued for 42 days, while at weekly intervals, 3 mice/group were necropsied for determination of body weight, cecal weight, liver zinc concentration, presence of S hyodysenteriae in the cecum, and gross and histologic assessments of cecal lesions. From postinoculation day 0 to 42, the liver zinc concentration of mice fed the zinc-supplemented diets was approximately twice that of mice fed the basal diet, irrespective of the source of zinc. From postinoculation day 7 through 42, the overall recovery rate of S hyodysenteriae in infected mice fed the basal diet was 77.8%. In contrast, recovery rates of S hyodysenteriae from S hyodysenteriae-inoculated mice fed the zinc-supplemented diets were 0% for Zn-methionine and ZnO and 16.7% for ZnSO4. Mice fed the basal diet had significantly (P < 0.05) higher weight gain than mice fed the zinc-supplemented diets. However, the severity of cecal lesions, as determined by histologic examination and quantitative determination of longitudinal crypt length of the cecum was significantly (P < 0.05) less in mice fed the zinc-supplemented diets than in mice fed the basal diet. Data from this study indicate that dietary supplementation with 6,000 mg of zinc/kg of feed significantly reduced the recovery rate of S hyodysenteriae and provided partial protection against development of cecal lesions in mice inoculated with S hyodysenteriae. However, at this concentration, zinc had a deleterious effect on growth of the mice.

Properties of the attachment of Treponema hyodysenteriae to Henle intestinal epithelial (HIE 407) cells were examined. The frequency of attachment depended on the motility and viability of the spirochetes. Rabbit hyperimmune and swine convalescent antisera inhibited attachment. Treatment of HIE cells with neuraminidase had no effect on attachment; however, treatment of spirochetes with the enzyme decreased adherence significantly (P = 0.01). Attachment was inhibited by N-acetylneuraminic acid, D-glucuronic acid, and fetuin. Adherence was increased following coincubation with N-acetylglucosamine or yeast mannan. Surface antigens of T hyodysenteriae, isolated by chemical extraction, competitively inhibited adherence. Concentrated T hyodysenteriae culture supernatant fractions inhibited adherence, but concentrated phosphate buffered-saline washings of the spirochete and concentrated uninoculated media did not inhibit adherence. Sialic acid was detected in unwashed T hyodysenteriae and spent culture supernatant fractions in higher concentrations than from washed spirochetes and uninoculated media. It was concluded that the binding adhesins on T hyodysenteriae for cultured HIE cells may contain sialic acid residues.

In this study, we performed a PCR-RFLP analysis of NADH oxidase gene(nox) for the characterization of porcine intestinal spirochetes isolated from Korea by the comparison with Brachyspira hyodysenteriae and B. pilosicoli reference strains. Eleven strains including four reference strains, B. hyodysenteriae B204, B234, B169, B. pilosicoli P43/6/78 and seven Korean isolates were used. PCR products of 939 bp were amplified using nox-specific primers and digested with two restriction enzymes, Bfm I and Dpn Ⅱ.