Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Gilbert E. Ward x
  • Refine by Access: All Content x
Clear All Modify Search

SUMMARY

Intestinal tissues from swine affected with proliferative enteritis were ground, filtered through a 0.65-μm pore membrane filter, diluted, and injected into 7-day-old embryonated hens’ eggs via the yolk sac. At 2, 4, and 7 days later, yolk sac swab specimens taken from live embryos were cultured for Campylobacter species. Campylobacter hyointestinalis was recovered from eggs injected with tissues of swine with acute hemorrhagic proliferative enteritis at dilutions up to 10−4. Campylobacter mucosalis was recovered from eggs injected with tissues of swine with chronic proliferative enteritis at dilutions up to 10−6. Campylobacter coli was recovered from several specimens without lesions of proliferative enteritis and also from some specimens with lesions of proliferative enteritis. Two previously undescribed hemolytic Campylobacter species designed as hemolytic number 1 and hemolytic number 2 were recovered from normal and experimentally inoculated swine tissues. Few contaminating organisms grow in eggs and these were usually recovered at dilutions of 10−2 or less. Recovery of Campylobacter species by use of these techniques was seldom successful in tissues stored at −70 C for more than 6 months.

Free access
in American Journal of Veterinary Research

Summary

Embryonating eggs were inoculated with filtered porcine ileal mucosa containing intracellular curved rods (icr) and incubated for 4 to 6 days. Three of 12 pigs given the eggs per os developed microscopic lesions of proliferative enteritis (pe). Nonchallenge-exposed control pigs did not develop lesions of pe. Four of six positive control pigs given ileal mucosa from pigs with pe also developed microscopic lesions of pe. All of the PE lesions were found in pigs necropsied 10 to 29 days after challenge exposure. None of the swine in the study had clinical signs or gross lesions of pe.

Campylobacter spp were isolated from pigs with and without exposure to the ileal mucosa from pigs with pe. There was no relationship between Campylobacter spp isolation and development of lesions.

Deoxyribonucleic acids extracted from embryonating chicken eggs injected with the equivalent of 0.5 mg of mucosal lesions and incubated for 4 days hybridized to a dna probe specific for the icr, whereas dna extracted from 1.5 mg of mucosal homogenates of the same proliferative tissue did not hybridize with the same probe. Results of these experiments indicated that icr injected into eggs remained infective for pigs and suggest replication of icr in the first-passage eggs.

Free access
in American Journal of Veterinary Research

Summary

A method of extracting bacterial dna from swine feces was developed and used in a molecular assay for the presence of ileal symbiont (is) intracellularis, formerly known as the Campylobacter-like organism associated with swine with proliferative enteritis. Hybridization with a digoxigenin-labeled, is intracellularis-specific probe detected the presence of is intracellularis at a concentration of 107 organisms/g of feces. This method was sufficient to detect is intracellularis in the feces of swine with experimentally induced and naturally acquired infection. Results of the hybridization were in agreement with those from histologic postmortem examination.

Free access
in American Journal of Veterinary Research

Summary

In an abattoir-based case-control study, histologic, and macroscopic examination of porcine intestines at slaughter and 2 molecular assays were compared for use as diagnostic tests of proliferative enteritis (pe). Fecal samples and intestinal specimens were collected from pigs with grossly thick ileum and from clinically normal pigs at slaughter. Tissue specimens were fixed in neutral buffered 10% formalin, and sectioned. Sections stained with H&E were examined for proliferative lesions by a pathologist unaware of the group to which the pig had been assigned on the basis of results of gross examination. Adjacent tissue sections, stained with Warthin-Starry (silver) stain, were examined for presence of the intracellular bacterium of pe, ileal symbiont (is)-intracellularis, in the enterocytes of the intestinal crypts by the senior author, who was unaware either of the group to which the pig had been assigned or diagnosis by the pathologist. Bacterial DNA was extracted from the fecal samples and assayed by dot-blot hybridization and polymerase chain reaction (pcr) for presence of is-intracellularis dna, without knowledge of results of the other examinations. The pcr assay for is-intracellularis was a specific and sensitive diagnostic test for pe, and dot-blot hybridization was sensitive, but was less specific. Macroscopic examination of intestines at slaughter was a sensitive, but not specific, test.

Association between is-intracellularis and proliferative lesions was statistically examined in the same study. There was a highly significant (P = 0.0078) association between presence of naturally acquired proliferative lesions and intracellular infection induced by is-intracellularis. The odds ratio of ≥ 14 and estimated attributable fraction of ≥ 92% indicate that is-intracellularis may be a necessary cause of pe.

Free access
in American Journal of Veterinary Research