Veterinary Services

Streptococcus suis serotype 2 infection was the cause of death of an eight-week-old boar. There were four sudden deaths of pigs in good body condition in the space of one week on the unit. At necropsy there was fibrinous polyserositis and polyarthritis, affecting all of the locomotor joints. The organism was isolated in culture from the brain, joints and pericardium.

Streptococcus suis serotype 3 septicaemia was diagnosed in a sixteen-day-old Tamworth cross piglet. At postmortem examination, there were slight thickenings of the left atrioventricular valves and fawn discolouration of the ventral aspects of the cranial and middle lung lobes. There was also slight cloudiness of the cerebellum. Streptococcus suis serotype 3 was isolated from the lung, liver, brain and heart valve lesions. On histopathology there was evidence of acute endocarditis with heavy bacterial colonisation. The myocardium had a sizeable area of infarction with acute necrotising changes. In addition there was exudative broncho-interstitial pneumonia with bacterial emboli in some of the blood vessels. The brain had widespread lesions of exudative meningitis and purulent inflammation in the fourth ventricle and hypothalamus.

Erysipelas was diagnosed in a four-month-old gilt. Ten deaths occurred and there were signs of dyspnoea, cyanotic ears and loss of body condition since they arrived on the unit five weeks previously. There was a fibrinous pericarditis and verrucose lesions on the left atrioventricular valve. There was also evidence of arthritis affecting the right stifle joint. Erysipelothrix rhusiopathiae was isolated in culture from the heart valve lesions.

Alimentary tract disorders

Evidence of viral enteritis, possibly due to rotavirus infection, was detected on histopathology of intestine from diarrhoeic piglets at a few days of age but rotavirus was not detected in the PAGE test. The two piglets submitted for postmortem examination had evidence of good colostral absorption. On histopathology one piglet had widespread oedema of the villi with detachment of the surface epithelium and early atrophy of the lamina propria. The epithelium presented as large balloons on the villi or ribbons coming off the villi. There was no evidence of any inflammatory changes. The other piglet had villus atrophy and attenuation of the epithelium in both the small and large intestine. In both cases SAC C VS considered the changes were suggestive of a viral aetiology.

Salmonella Typhimurium DT 120 infections were diagnosed in seven-week-old pigs which were in poor body condition. There were 14 deaths in 12 hours on the unit with only one pen reported to be affected. Three pigs submitted for postmortem examination had evidence of necrotic typhlo-colitis and in some there was also evidence of enteritis. Another pig showed evidence of acute enteritis and superficial, diphtheritic gastritis. Histopathology confirmed the presence of necrotising bacterial enteritis in the affected pigs, consistent with a diagnosis of salmonellosis.

Respiratory disorders

Bacterial pleuropneumonia due to a mixed infection with Actinobacillus pleuropneumoniae, Pasteurella multocida and Arcanobacterium pyogenes was confirmed in a four-month-old finisher from a unit with a history of sudden deaths and some coughing. Actinobacillus pleuropneumoniae was isolated from the lung of another affected pig from the same building. Both pigs were in good body condition but necropsy revealed an excess of fibrinous pleural fluid and extensive areas of consolidation and hepatisation affecting the anteroventral parts of all lung lobes. There were also extensive areas of fibrinous pleurisy, with adhesions between lung lobes and between the lungs and thoracic wall.

Deaths due to Pasteurella multocida pneumonia and pathology that suggested enzootic pneumonia (EP) were confirmed in four-month-old pigs on straw courts. Coughing and increased mortality rates were reported. In addition, Glasser’s disease was diagnosed in one of the pigs submitted, which had a severe fibrinous pericarditis and pleuropneumonia.