Veterinary Services

Meningitis due to Streptococcus suis serotype 2 was diagnosed in 20-week-old finishing pigs. Two pigs had shown nervous signs and ten pigs in the group of 130 were lame. The organism was isolated from the brains of two pigs. Neither showed gross evidence of arthritis or osteochondrosis.  S. suis serotype 2 infection was also diagnosed in a five-week-old gilt. Five had died in the same pen in 24 hours.   

Streptococcus suis serotype 14 infection was diagnosed in a 21-week-old gilt from a unit where there were three sudden deaths in two days. Coughing was also reported and the pigs were receiving tylosin in-feed as a result. The lungs appeared congested, oedematous and had haemorrhages throughout. There was submucosal haemorrhage in the trachea. The meningeal vessels were very injected. S. suis serotype 14 was isolated from the lung and brain.

PDNS was diagnosed on twice in four to five-month-old Hampshire cross finishing pigs. The affected pigs were in good body condition and died suddenly. Petechiated renal cortices were detected at postmortem and in one case the kidneys were very congested and had subcapsular haemorrhage. Histopathology revealed severe diffuse glomerulonephritis, with abundant protein loss, hyaline cast formation and vasculitis. In both cases the lymphoid follicles were necrotic and multi-nucleated giant cells were present, suggesting that PCV-2 was involved.

Locomotor conditions

An investigation was carried out into the cause of outdoor sows showing hindlimb paresis, which progressed to ataxia, hindlimb paralysis and dragging of hindlimbs. Two or three sows were affected over a three week period. No central nervous signs were reported and the sows remained bright and continued to eat.  Neuropathology of the lumbar spinal cord showed pronounced perivascular lymphocytic cuffing affecting capillaries in the white and grey matter, the pia mater and ventral fissure. The subacute to chronic myelitis suggested a viral type insult but the cause was not established.

Alimentary tract disorders

Acute, profuse diarrhoea due to Salmonella Typhimurium phage type 120 infection was diagnosed in 12-week-old gilts that arrived on a unit six days previously. Ten pigs were dull and weak and one died.  In a separate incident, a batch of 4-week-old weaners was bought in from a single source for a feed trial.  On arrival they appeared healthy and bright although some had dark diarrhoea and there was a marked variation in body weight (5 to 10 kg).  Two died within the first three days and were submitted for postmortem examination.  Both were thin and dehydrated and showed necrotising enteritis of the jejunum and ileum.  Salmonella Typhimurium pt 104 was isolated from both.  Treatment was initiated but a third pig died one week later.  In this pig there was dramatic thickening and necrosis of the mucosa of the caecum and large colon.  Again culture yielded S. typhimurium pt 104.

Post-weaning enteritis was a widespread and ongoing problem for a unit in which Lawsonia intracellularis was confirmed as the cause of ileitis and typhlocolitis in one group of 50 weaned pigs. The mortality rate was ten percent within a week.  Many of the piglets, that were previously affected with enteritis recovered after a period of a few weeks. The piglets had been treated with tiamulin in feed from four and a half to seven weeks of age, and vaccinated against circovirus and Mycoplasma hyopneumoniae. Clinical signs began at around eight weeks of age, just after the antibiotic treatment ceased. Yersinia enterocolitica were also isolated from two affected animals. This pathogen was considered to be secondary and of little significance based on the gross and histopathological findings in the gut tissues.  However the zoonotic potential of Yersinia sp was highlighted. Lesions suggestive of enzootic pneumonia were also detected on the lung sections examined by histopathology.