Gastro-intestinal lesions are not relatable to diarrhoea or specific pathogens in post-weaning diarrhoea (PWD) in pigs

Abstract

Background Post-weaning diarrhoea (PWD) is a multifactorial condition and the most well documented infectious cause is enterotoxigenic Escherichia coli. The objective of the study was to investigate possible associations between pathological manifestations and pathogens in pigs with and without PWD. The study was conducted as a case–control study and included a total of 173 pigs from 9 different commercial intensive indoor production herds in eastern Denmark. Results Based on clinical examination, a total of 89 piglets with PWD (cases) and 84 piglets without PWD (controls) were included. Most of the pigs (n = 105/173) presented gastric lesions, which were more frequently observed in the control group. The odds of gastric ulcers were lower among pigs with PWD compared to pigs without PWD with an odds ratio (OR) of 0.2 (0.0; 0.7). Abnormal content in the colon was associated with PWD, with an OR of 6.5 (3.2; 14.3). No apparent association was found between lesions and the various pathogens or a combination of these. The odds of neutrophilic granulocyte infiltration were lower in the jejunum among pigs with PWD (OR 0.3 [0.1; 0.6]) compared to pigs without PWD. The association between neutrophilic granulocyte infiltration in jejunum and PWD differed between the herds (P = 0.03). Furthermore, the associations between PWD and hyperleukocytosis (P = 0.04) or infiltration of eosinophilic granulocytes (P = 0.04) in ileum were also herd dependent. Histopathology revealed several lesions not relatable to PWD. Conclusion The association between lesions and specific pathogens or PWD is more complex than anticipated.

An observational field study of porcine post-weaning diarrhea: clinical and microbiological findings, and fecal pH-measurements as a potential diagnostic tool

“…An additional fecal sample was collected from the rectum of all case and control pigs using a sterile cotton swab (OneMed, Helsinki, Finland) that was immediately placed in tubes with 5 of mL sterile phosphate buffered saline (PBS) solution [ 41 ]. The samples were transported to the laboratory in cooling boxes with ice and analyzed to detect intestinal pathogens that we hypothesized could be involved in the causation of PWD.…”

“…The samples were transported to the laboratory in cooling boxes with ice and analyzed to detect intestinal pathogens that we hypothesized could be involved in the causation of PWD. The microbiological laboratory diagnostics are described in detail elsewhere [ 41 ]. In brief, we used culture-based methods supplemented by matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) and PCR genotyping to detect Clostridium perfringens, E. coli (ETEC and non-ETEC), and Samonella enterica spp.…”

“…A high-throughput real-time PCR platform, BioMark HD (Fluidigm, San Francisco, California), and a 192.24 dynamic array integrated fluidic circuit system (Fluidigm) were used to quantify Brachyspira pilosicoli , E. coli fimbrial types F4 and F18, Lawsonia intracellularis, porcine circovirus type 2, porcine circovirus type 3, rotavirus A, rotavirus B, rotavirus C, and rotavirus H [ 42 ]. For a complete description of the procedure, we refer to the paper relating the microbiology to the pathological lesions [ 41 ]. Rotavirus B, C, and H were not part of the previously described platform [ 42 ], and the primer and probe sequences will be published elsewhere.…”

“…The extent of the growth of hemolytic E. coli-like colonies was estimated semi-quantitatively [ 1 , 41 ]. This information was missing for pigs from Herds E and F. This precluded the essential quantitative interpretation of ETEC diagnostics based on the culture results [ 11 ].…”

“…The selected cases and controls (sampling stage 3) were stunned with a captive bolt and euthanized by exsanguination as the last procedure during a herd visit. The pigs were transported to the University of Copenhagen, Frederiksberg, and stored at 4 °C until the next morning, where a post-mortem exam focusing on the gastrointestinal tract was performed [ 41 ]. The intestines were removed from the abdominal cavity, and the appearance and content of all segments of the intestine were inspected.…”