Veterinary Services

Generalised and systemic conditions

A nine-year-old female Pot-bellied pig kept as pet was found dead in its kennel. The pig was lethargic, anorexic and hypothermic in the 24 to 48 hours prior to death. At necropsy the animal was in excellent bodily condition, with evidence of substantial fat reserves throughout. The primary finding was that both kidneys were heavily petechiated and the bladder contained a small quantity of blood-stained urine. More limited petechiation was also noted on the mucosa of the stomach. On histopathology, both kidneys showed widespread chronic interstitial nephritis and fibrosis affecting both cortex and medulla. The SAC suspected that the sow previously had pyelonephritis that had caused significant interstitial reaction and progressive fibrosis leading to renal failure.

Alimentary tract disorders

An outdoor breeding unit experienced increasing numbers of scouring piglets from one-day of age despite the sows being vaccinated against E.coli. A three-day-old piglet showed oedema of the lamina propria at the villus tips and early detachment of the epithelium. This was consistent with a very early viral type enteropathy such as rotavirus but rotavirus was not detected. This failure may be due to the very early stage of infection or the intermittent shedding of small numbers of organisms. A 14-day-old pig had no evidence of enteritis at gross postmortem or on histopathology. However occasional coccidial forms were present on histopathological examination of the small intestines that suggests coccidiosis could have caused problems at this stage.

Wasting and scouring affected a few batches of pigs of different ages on a breeder-finisher unit. An eight-week-old and a 14-week-old pig were submitted for postmortem examination. Both pigs had hyperaemic and thickened colonic and caecal walls. The large intestinal contents of the younger pig appeared to contain blood and small areas of necrosis present in the colonic mucosa in the older pig. Brachyspira hyodysenteriae was isolated in culture from the younger pig and the organism was detected by PCR in the older pig. Therefore swine dysentery was the likely cause of the diarrhoea. Lawsonia was also detected by PCR in the older pig indicating that there was a mixed infection present. The lymph nodes were depleted in both pigs but there was insufficient evidence to indicate postweaning multisystemic wasting syndrome (PMWS) involvement.

A pooled faecal sample was submitted from five-month-old Tamworth pigs that were vomiting four to five days previously. The worm egg count was high (7,100 Ascaris species plus 100 strongyle eggs per gram). Intestinal parasitism was considered to be responsible for the clinical signs and anthelmintic treatment was advised. No significant organisms were isolated in culture and rotavirus was not detected.

Detailed investigations revealed mixed enteric infections as the cause of wasting and scour in pigs aged nine to 10-weeks-old from two unrelated units. Seven pigs were submitted over the space of one week from the first, an outdoor organic unit. Four gilts showed thickening and hyperaemia of the terminal 20 to 30 cm of ileum that also had a necrotic mucosa. The colonic mucosa was also thickened (figure 5 - see top right-hand side). Histopathology revealed a proliferative enteropathy consistent with Lawsonia intracellularis infection with evidence of secondary necrotising bacterial infection. Lawsonia intracellularis was detected by PCR. One gilt with intestines that appeared normal on gross examination showed evidence of PMWS-type lesions of the lymph nodes on histopathology. The boars on the unit had evidence of colitis with greyish, slurry-like colonic contents. In some of the boars the large intestines contained a large volume of gritty silt material. Brachyspira pilosicoli was detected by PCR indicating a diagnosis of porcine colonic spirochaetosis. A nine-week-old boar from another batch had frothy pale, large intestinal contents in which Brachyspira hyodysenteriae and Lawsonia intracellularis were detected by PCR. Salmonella Typhimurium phage type U302 was also isolated from this boar.

Only faecal samples were submitted from the second unrelated unit. Yersinia enterocolitica and Salmonella Typhimurium phage type U302 were isolated in culture and Lawsonia intracellularis was detected by PCR. Mixed enteric infections also occurred on this unit.