Veterinary Services

Generalised and systemic conditions

Porcine dermatitis and nephropathy syndrome (PDNS) with concomitant post-weaning multisystemic wasting syndrome (PMWS) was diagnosed in a three-month-old pig which had died following a short history of apparent weakness. The 180-sow unit had lost around ten pigs with similar signs over the last year. Skin lesions of PDNS were not observed in this pig or in any of the others noted on the unit. The generally good post-weaning performance had not prompted prior submission of material to the laboratory and this was the first time that PMWS had been diagnosed on this unit.

Streptococcus suis infection was diagnosed in a two-week-old Large White piglet. The unit of origin reported several deaths of 10-14 day old piglets with clinical signs of arthritis, and post mortem evidence suggestive of septicaemia and pericarditis. Fibrinous pericarditis was evident in the case examined. S. suis biotype II was isolated from the pericardial lesions and the brain. The isolate was not serotyped.

Alimentary tract disorders

Two freshly euthanased ten-week-old pigs were submitted from a nursery unit reporting loss of condition and some diarrhoea, apparently associated with a change in feed. Colitis was noted in both pigs and histopathological examination revealed surface epithelial erosion and mild mononuclear cell infiltration in the lamina propria, consistent with non-specific (diet-associated) colitis. In addition, in one of the animals there was crypt abscessation and mucus-filled crypts with evidence of mixed bacterial types involved, suggestive of opportunistic bacterial infection; no significant enteropathogens were isolated on culture. Such lesions are a relatively common finding in pigs with PMWS and indeed mild lesions of lymphoid depletion and histiocytic infiltration consistent with PMWS were observed in lymphoid tissues of one pig and the ileum of the other.

A similar problem of diarrhoea following diet change in three-month-old pigs on another unit was reported. Morbidity increased from around 10% one week after the change to 60-70% after two weeks, but no associated mortality was reported. Two affected pigs were submitted for post mortem examination. Histopathological evidence of non-specific colitis was observed in one of the pigs (no evidence of bacterial involvement), while in the other there was evidence of proliferative enteropathy. It was therefore concluded that both feed-associated colitis and Lawsonia intracellularis infection may be contributing to the scour problem on this unit.

Yersinia enterocolitica was isolated from each of four faecal samples from four-month-old scouring pigs on an indoor unit. Although no other enteropathogens were detected, the significance of the isolations to the unit problem is not clear.

Examination of a twelve-month-old large white boar that had been found dead with no history of previous illness revealed acute peritonitis subsequent to perforation of the ileum. Marked thickening of the muscularis/submucosa of the ileum was noted, without any apparent mucosal lesions. The rupture appeared to have occurred close to the most severely affected area. Idiopathic ileal muscular hypertrophy was suspected and confirmed by histopathological examination which demonstrated marked hyperplasia of both the circular and longitudinal layers of the intestinal muscularis. The ileal mucosa was sacculated but appeared otherwise normal. No intestinal obstruction was detected distal to this site and it seems likely that perforation had occurred following impaction of material in the affected area of intestine.

Respiratory tract diseases

An enzootic pneumonia "breakdown" was confirmed in one herd following the observation of suspicious lung lesions during quarterly abattoir viscera inspections (Wholesome Pigs Scotland). Lung tissue from affected pigs tested positive for Mycoplasma hyopneumoniae-specific DNA by polymerase chain reaction (PCR).

Nervous system disorders

Oedema disease was diagnosed in a two-month-old male wild boar showing neurological signs that had failed to respond to treatment with amoxycillin. The animal, which was the only one reported to be affected in a group of 37, presented in lateral recumbency and showing paddling movements. Bacterial meningitis was initially suspected but only a scant growth of mixed bacteria was isolated from the brain. However neurohistopathological examination revealed cerebrovascular angiopathy consistent with an enterotoxaemic E. coli (ETEEC) infection, although culture of intestinal contents was not performed. No other pathology suggestive of oedema disease was noted on gross post mortem examination.