Veterinary Services

Two live piglets, less than 24 hours old, were submitted to investigate problems with newborn pigs over the last six months. Affected pigs appeared anaemic, their skin scratched easily and there was variation in size within a litter.  Navel bleeding was not a feature but some piglets subsequently bled to death. Both submitted piglets had scratch marks on the skin over the muzzle, face and ears. There was bruising of the tissues in the mouth adjacent to the canine teeth and one pig had a bruise overlying the left knee joint. Following blood sampling and euthanasia, severe internal haemorrhage was seen in both. On cutting the base of the navel, there was profuse bleeding without clotting. Apart from pallor of internal organs, there were no other gross changes. Both pigs had a severe normochromic normocytic anaemia suggestive of an early acute haemolytic anaemia. There were adequate numbers of platelets. On histopathology both piglets had exudative epidermitis and one pig showed ulcerated skin lesions with subacute inflammation and folliculitis with bacterial infection. Tooth root infection was also apparent. All areas were haemorrhagic. The haemorrhagic lesions appeared to be directly related to bacterial infection and inflammation. From the age and location of lesions, infection must have occurred in utero, suggesting bacteraemia and placentitis in the sows. Further investigation into the cause of the anaemia problems is underway.

An 18-day-old piglet was submitted with extensor rigor of the hind limbs. The limbs could be manually flexed and there was a withdrawal reflex. Underlying the psoas muscles was a smooth bilateral pale swelling attached to the ventral surface of the vertebrae. On cross–section it consisted of pale cellular tissue with a rubbery texture and areas of grittiness. On histopathology the lesion comprised fibrous tissue containing cartilage in a haphazard arrangement. Some of the cartilaginous elements had undergone ossification. The lesion resembled a congenital ossifying fibroma possibly arising from the periosteum of the lumbar vertebra. It was likely to be a sporadic case and is very rare in pigs.

Several units across Scotland encountered problems associated with Streptococcus suis infections.  A nine-day-old and two 26-day-old pre-weaned piglets were submitted from one unit. The two older piglets had vegetative lesions affecting the left atrioventricular (AV) valve plus evidence of septicaemia and polyarthritis. An untypeable Streptococcus suis was isolated from the lungs, heart valves, brain, liver and joints. The isolate was multi-resistant. The younger piglet had navel-ill from which an untypeable Streptococcus suis was isolated. There was also a small vegetative lesion on one of the left AV valves.

Further cases of Streptococcus suis serotype 2 infections were diagnosed on four previously unaffected units. These were under the same ownership as a unit in which an outbreak was first diagnosed in July. In a typical submission, S.suis serotype 2 infections were confirmed in two, 16-week-old pigs. An untypeable S.suis was isolated from the lung and S.suis serotype 22 was isolated from the brain of a third pig with signs of meningitis, arthritis and pneumonia.

Another unit under the same ownership had more cases of meningitis, arthritis and septicaemia due to Streptococcus suis serotype 1/14 infection. This unit has not had any cases of Streptococcus suis serotype 2 infection diagnosed. Two sows that produced litters affected with S. suis serotype 1/14 infections were submitted for S. suis screening. In one sow the following S. suis serotypes were isolated from the tonsils: 20, 22, 24 and 31/33. In the other sow S. suis serotypes 16, 20 and 22 were isolated from the tonsils. No S. suis isolations were made from vaginal swabs in either case.

An unrelated unit reported losses in nine-week-old pigs in good condition. Two pigs submitted for postmortem examination had polyarthritis and one also had polyserositis.  Streptococcus suis serotype 2 was isolated from systemic and joint cultures and from the brain of one pig.

Meningitis due to infection with Streptococcus suis serotype 1/14 was diagnosed on the basis of post mortem examination and microbiology in two 26-day-old rearing pigs from two separate units within a breeding pyramid.

Alimentary tract disorders

Clinical signs and gross pathology in diarrhoeic three-day-old piglets from an outdoor unit in Aberdeenshire were suggestive of Clostridium perfringens type C infection. A vaccination programme had recently been put in place against Clostridium perfringens infection. This was the first batch of piglets to be born after completion of the vaccination course. It was reported that a small proportion of piglets were affected in a third of the litters, from one day of age. Antibiotic treatment prolonged the lives of the affected piglets but they often died one to two weeks later after continuing to scour. Histopathology confirmed the presence of an acute necrotising enteritis, with widespread invasion of the damaged mucosa by Gram positive clostridial type bacteria. The organisms were not isolated in anaerobic cultures.

Wasting and scour in 10 to 14-day-old piglets were investigated on one unit in Aberdeenshire.  Three piglets had fibrinous peritonitis and adhesions between adjacent loops of intestines. There was gross evidence of necrotic enteritis. This was confirmed on histopathology with intestinal ulceration and inflammation of all layers of the intestinal wall associated with heavy colonisation by Gram positive rods. The findings were consistent with an acute clostridial type enteritis. It was not possible to demonstrate the organisms in anaerobic cultures.

Colitis, highly suggestive of Brachyspira pilosicoli infection, was diagnosed in two, thin, six-week-old pigs from a unit where there was a recent increase in mortality. On histopathology there was subacute bacterial-type colitis with crypt inflammation, goblet cell hyperplasia, increased mucus production and surface epithelial erosion. Silver staining showed moderate colonisation of colonic crypts with large fine spirochaetes.

Bacterial-type colitis associated with spirochaetal infection was diagnosed by histopathology in twelve-week-old pigs with diarrhoea. Three sows were found dead one morning and submitted for postmortem examination.  The first had a splenic torsion with rupture and haemorrhage.  The second had a mesenteric torsion.  SAC considered that both conditions could be related to whey feeding.  The third had a bloated stomach but there was no evidence of whey within it.