Veterinary Services

Four outbreaks of meningitis associated with Streptococcus suis serotype 2 occurred on unrelated units. In three of the outbreaks the pigs also showed lameness due to polyserositis. In the fourth there was pneumonia and/or pericarditis in addition to meningitis. Typically, the histories reported sudden deaths of between three and twelve pigs over a two-to-three day period and clinical illness, mainly lameness or neurological disease in larger numbers of pigs within the groups.

Two other outbreaks of meningitis and coughing involved less common serotypes.  One outbreak affecting 20-week-old gilts involved Streptococcus suis serotype 4 Sixteen from a total of 154 pigs died over a three day period. Histopathology confirmed the presence of semi-purulent meningitis affecting the cerebellum, brainstem and cerebrum. The other outbreak involved Streptococcus suis serotype 22 in 19-week-old finishers. Histopathology confirmed extensive lesions of bacterial-type meningitis.

Reproductive conditions

Severe septic endometritis due to Staphylococcus hyicus infection was diagnosed in a year-old sow from a 1,000 sow unit with a history of poor conception rates (85 per cent). Two to four per cent of sows were reported to have resorbed foetuses, having been scanned in-pig. In the sow submitted, both uterine horns contained yellow purulent material attached to a hyperaemic endometrium. A profuse, pure growth of Staphylococcus hyicus was isolated from the uterus. Histopathology revealed severe endometritis with congestion, haemorrhage and oedema. There was widespread erosion of the endometrium and associated bacterial colonisation of the lesions.

Locomotor conditions

A one-year-old sow was submitted for postmortem examination to investigate the cause of lameness affecting almost a third of a pen of 24 yearling sows. The acetabulum and femoral heads on each side were distorted and oval in outline. The femoral heads had irregular ridges extending round the medial aspects. The articular cartilages of the trochlea and condyles of the distal femurs were irregular in appearance and thickness. The tissues surrounding the stifle and shoulder joints were congested and rather thickened. The gross pathology was suggestive of osteochondrosis and this was confirmed by histopathology. Bacterial cultures from the right shoulder, right stifle or left elbow joints were sterile and no significant Mycoplasmas were detected. 

Respiratory conditions

Pneumonia and sudden deaths were reported in eight-week-old pigs which were on a unit for four weeks. The morbidity was ten percent and there were 16 deaths. The pigs were vaccinated against enzootic pneumonia and porcine coronavirus 2 (PCV2). A gilt submitted for postmortem examination had pale pink consolidation of the anterior lung lobes and deep purple consolidation and congestion of the diaphragmatic lobes. Pasteurella multocida was isolated as part of a mixed growth from the lung. Lung histopathology showed widespread subacute, active interstitial pneumonia with mixed, mainly mononuclear cell infiltration of the interstitial tissue and some alveolar spaces. The lymph nodes showed many mixed inflammatory cell infiltrates in cortical areas but were depleted of lymphoid follicles. The findings were highly suggestive of porcine respiratory reproductive syndrome (PRRS) infection. This was confirmed by a positive PRRS PCR result. The lymphoid depletion suggested that PCV2 was also playing a role.

Enzootic pneumonia was diagnosed in a unit where 50 percent of 150 finishers showed respiratory signs. The lungs of an 18 week-old boar examined post mortem were congested and showed irregular areas of consolidation affecting the apical lobes and parts of the diaphragmatic lobes. The serosal surfaces of the large intestines and other peritoneal membranes were thickened and had areas of congestion. Histopathology confirmed widespread chronic bronchiolitis and interstitial pneumonia, with a well established peri-bronchiolar and perivascular cuffing reaction. There was also evidence of subacute pleurisy and bacterial involvement. The findings suggested enzootic-type pneumonia with secondary bacterial infection and the detection of Mycoplasma hyopneumoniae in lung tissue by PCR confirmed the diagnosis.

Alimentary Tract Conditions

Enteritis due to Clostridium perfringens infection was diagnosed in a herd experiencing a scour problem for a month in piglets from one day of age. Two live and two dead one-day-old piglets were submitted. The dead piglets were in poor body condition whereas the live piglets were in reasonable condition but had profuse yellow diarrhoea. The small intestines contained yellow, flocculent fluid and the large intestines had liquid yellow contents. Clostridium perfringens was isolated from the intestinal contents of both piglets. On histopathology there was acute epithelial necrosis and large numbers of clostridial-type bacteria colonising the villi with proteinaceous fluid secreted into the intestinal tract.