Veterinary Services

Generalised and systemic diseases

Post-weaning Multisystemic Wasting Syndrome (PMWS) was diagnosed in a pig unit in Fife that reported increased mortality and ill thrift among all ages of pigs. Five pigs aged from eight to 20-weeks-old were submitted for examination. Their bodily condition was poor. The diagnosis of PMWS was made on the basis of gross findings of lymphadenopathy and nephropathy, the histopathological appearance of lymph nodes and the demonstration of Porcine Circovirus type 2 (PCV-2) in lymph nodes by immuno-histochemistry.

Meningitis and sneezing were the main clinical signs reported by an Aberdeenshire unit where ten of approximately 340 weaned pigs died over a month. A 30-kg pig showed congested, oedematous lungs, enlarged submandibular and inguinal lymph nodes, excess synovial fluid in the elbows, stifles and hocks and excess turbid fluid under the meninges, especially over the cerebellum and brainstem. Streptococcus suis serotype 2 was isolated in culture from the brain and joints.

Alimentary tract disorders

A combination of proliferative enteropathy and colitis associated with the isolation of Brachyspira pilosicoli from the large intestinal contents was diagnosed as the cause of weight loss and scouring affecting pigs in the fattening houses of an Aberdeenshire unit. The pigs received lincospectin from seven to 12 weeks of age and were then moved to larger sheds where they received intermittent medication with chlortetracycline. Two pigs in very poor body condition submitted for examination showed thickening and hyperaemia of the ileum and in one pig there was also ulceration and fibrin accumulation. The caecal mucosa was hyperaemic and the mesenteric lymph nodes were prominent.

Two seven-week-old pigs were submitted from a nursery unit where pigs were failing to thrive at the first stage and loose faeces had been noted. The appetite was reduced and about 30 per cent of the 200 pigs in the batch were affected. The colonic contents were of thick liquid consistency, yellowish-brown and very mucoid. Brachyspira hyodysenteriae was detected by PCR in one of the pigs. On histopathology the colon sections showed evidence of bacterial-type colitis with mucosal hypertrophy, goblet cell hyperplasia and bacteria in crypts.

An outdoor organic unit that weans at seven weeks of age, experienced an increased mortality rate of six to seven percent mainly due to sudden deaths. Two 11-week-old pigs were submitted for postmortem examination. In both cases the terminal ileum and the colon were thickened and the colonic mucosa had areas of necrosis. In one pig there were oedematous colonic folds and in the other there was necrosis of the mucosa of the terminal ileum. Lawsonia intracellularis was detected by PCR in a pooled sample of the colonic contents.

Respiratory tract disease

Porcine reproductive and respiratory syndrome (PRRS) was suspected to be the agent responsible for poor growth and coughing in a farrowing house in Aberdeen where 50 out of about 500 pigs were affected was reported in Aberdeen. One pig showed a fibrinous pericarditis and lobular consolidation of the lung. On histopathology there was a subacute bronchointerstitial pneumonia consistent with a viral-type pneumonia. There was also a bacterial component causing acute pleurisy with interstitial oedema and fibrin thromboemboli formation.

PRRS was also suspected in two-week-old piglets on another unit. About 10 out of 300 piglets were clinically affected. On histopathology of the lung there was a diffuse subacute interstitial pneumonia with mononuclear cell infiltration in alveolar septae. There was type II pneumocyte proliferation and a relative absence of alveolar macrophages with little change to the bronchiolar epithelium.

An organic unit submitted six pigs to Aberdeen to investigate the cause of pericarditis that led to the rejection of carcases at meat inspection. All six pigs showed fibrinous pleurisy, extensive pleuritic adhesions and a very severe fibrinopurulent pericarditis. There was also fibrinous perihepatitis and peritonitis. Glasser’s disease was suspected but there was no growth of Haemophilus parasuis in culture to confirm the diagnosis. A profuse growth of Pasteurella multocida was isolated in culture from the lung, liver and pericardium of one pig. The same organism was isolated from the lung of one other and the pericardium of a further pig. A profuse growth of Streptococcus suis serotype 2 was isolated from the lung of one of the pigs. Histopathology revealed complex pulmonary lesions comprised of enzootic-type pneumonia and bacterial infection, with viral involvement in one case. The bacterial and viral lesions were not specific.

A large breeding unit submitted four pigs between four and seven weeks of age, to investigate failure to thrive in the young pigs. There was coughing and sneezing from a young age in the farrowing house. The pigs were vaccinated against enzootic pneumonia (EP) at three weeks of age. The mortality rate was 20 pigs per week. Two 10-kg pigs had large volumes of clear, pale yellow thoracic fluid and interlobular lung oedema. One also had mild fibrinous pleurisy. On histopathology, both showed evidence of PMWS and a widespread viral-type pneumonia with alveolar and interlobular oedema. There were also degenerative changes affecting the endothelium of some capillaries, highly suggestive of PRRS virus involvement. A younger 3-kg pig was also submitted and it had evidence of EP. A fourth 3-kg pig that was thin and hairy had an umbilical abscess, polyarthritis and a dry, fibrinous pericarditis. Arcanobacterium pyogenes was isolated in culture from the umbilical abscess.