Veterinary Services

Generalised and systemic diseases

Streptococcus suis serotype 2 caused health problems on a number of units. In one outbreak, there was a sudden increase in mortality among weaners with clonical signs of meningitis. After five pigs were found dead one morning a live, affected pig was submitted for postmortem examination. The ten-week-old animal was in lateral recumbency, hyperaesthetic with muscle tremors on stimulation. It was pyrexic, showed congestion of the skin and ear tips and had swollen joints containing excess yellow synovial fluid.  Streptococcus suis serotype 2 was isolated in culture from lung, stifle and elbow joints and brain.

From a second nursery unit, three eight- to nine-week-old pigs were submitted to investigate the cause of sudden deaths and swollen joints.  The nursery is supplied with pigs from various sources. Two pigs submitted had no evidence of joint involvement but had excess, pale yellow, pericardial fluid with a few fibrin strands present. One pig had gross evidence of meningitis.The surface of the brain was oedematous, cloudy and grey. The other pig had injected meningeal vessels. Streptococcus suis serotype 2 was isolated from the brain of the first pig and from the liver, pericardial fluid and brain of the other. Pasteurella multocida was isolated in culture from the lung of the latter. The lungs had shown interlobular oedema and petechial haemorrhages.

Two seventeen-week-old boars were submitted from a third unit where Streptococcus suis serotype 2 was diagnosed four weeks previously. The pigs  had finished a course of in-feed penicillin ten days previously. Fifteen pigs had died from the group of 100. Both pigs had injected meningeal vessels and one had oedema and haemorrhage around the brain stem. Streptococcus suis serotype 2 was isolated in culture from the lung and brain of both pigs. The pigs had interstitial and interlobular oedema and one pig had marked lung congestion. Actinobacillus pleuropneumoniae was also isolated in culture from the lung of the latter pig.

Fifteen weaners were found dead on arrival at a rearing unit. The deaths all occurred in the rear section of the top deck of the transport. There was concern that the pigs were scouring but no evidence of this was found at postmortem examination. The three four-week-old pigs submitted all had external trauma affecting the skin and internal trauma with muscle and kidney bruising and cardiac haemorrhages. The presumptive diagnosis was trauma during transport.

Five sudden deaths occurred over the space of a week in a group of 70 finishing pigs. Most were found dead but some had been dull and appeared stiff before death. Two fifteen-week-old pigs were submitted for postmortem examination. Both had excess clear pericardial fluid and in one the heart was congested and had patchy pale areas. In both pigs some of the carcase muscles were very pale. One pig had an extensive fibrinous pleurisy affecting both lungs and small areas of pneumonia. It also had extensive fibrin tags attached to the peritoneal surfaces. Acute degenerative cardiomyopathy was confirmed in both pigs by histopathological examination.

Alimentary tract disorders

Spirochaetal colitis and Yersinia enterocolitica infection were confirmed in eight-week-old pigs submitted with a history of diarrhoea. The findings were similar in both pigs. There were yellow-brown liquid contents with undigested feed material present in the small intestines and distension of the large intestines with green liquid contents. The large intestinal mucosa appeared slightly thickened and oedematous. On histopathology the caecum and colon had widespread subacute inflammatory cell infiltrates, goblet cell hyperplasia and bacterial colonisation of crypts. One pig had large fine spirochaetes suggestive of Brachyspira pilosicoli present. However no Brachyspira species were isolated from the large intestinal contents.In the other pig there was colonisation of the crypts by small bacteria and no evidence of spirochaete involvement. In this case Yersinia enterocolitica was isolated in cultures of the large intestinal contents.