Veterinary Services

Porcine dermatitis and nephropathy syndrome (PDNS) was diagnosed in a nine-month-old wild boar submitted for necropsy following two weeks of malaise. Gross findings included haemorrhagic lymphadenopathy and multiple haemorrhages affecting the renal cortices and the epicardium. Histopathology confirmed a diagnosis of PDNS.

Postweaning multisystemic wasting syndrome (PMWS) was diagnosed in a seven-week-old pig submitted for necropsy. Pigs were seen to fade for three days prior to death and mortality increased to 1.5 per cent. Gross findings included fibrinous peritonitis.  On histopathology the lymph nodes and spleen showed marked lymphoid depletion consistent with PMWS-type changes. Vaccination against porcine circovirus type 2 and Mycoplasma hyopneumoniae had been carried out at weaning.

An outbreak of meningitis was diagnosed in 18-week-old boars from a unit where 34 had died over the previous three days. No bacteria were isolated but the pigs were previously treated with amoxicillin. The histopathological lesions were highly suggestive of virulent Streptococcus suis infection.

Respiratory tract disease

Swine influenza due to pandemic H1N1 (2009) virus was confirmed as the cause of acute onset coughing and respiratory distress for 36 hours in a group of 60 gilts. They had been outside and were housed 24 hours before the onset of clinical signs. Two were euthanased and submitted for postmortem examination. There were subserosal haemorrhages in the epiglottis and larynx. The tracheal mucosa was acutely congested with excess mucus and fibrin on the surface (Figure 4 - see top right-hand side). The lungs in both animals were very congested and oedematous with extensive well demarcated areas of congestion and hepatisation of the cranial lobes and to a lesser extent the middle and accessory lobes (Figure 5 - see top right-hand side).  The caudal lung lobes had multiple superficial petechiae (Figure 6 - see top right-hand side). On histopathology there was acute, severe tracheitis with vacuolation and acute degeneration of surface epithelium, widespread erosion and ulceration, acute inflammation, congestion and fibrin exudation. The lungs showed acute bronchiolitis with epithelial degeneration, necrosis and attenuation, acute interstitial pneumonia with early perivascular and peribronchiolar mononuclear cell infiltration. The findings were consistent with an acute viral-type tracheitis and bronchopneumonia, highly suggestive of swine influenza. This was confirmed when pandemic H1N1 (2009) virus was detected by PCR in the lungs from both pigs.

No evidence of swine influenza was found on investigation of another two large outbreaks of respiratory disease in unrelated units and testing. One outbreak involved seven deaths in a batch of 300 nine-week-old pigs. They were found to have acute viral-type pneumonia consistent with porcine respiratory and reproductive syndrome (PRRS) virus infection. In the second outbreak, there were 36 deaths in a batch of 16-week-old finishing pigs associated with severe pleuropneumonia and polyserositis. Affected pigs had a history of lameness, coughing and lethargy. Pasteurella multocida and Arcanobacterium pyogenes were the only organisms isolated from the lung lesions.

Alimentary tract disorders

Swine dysentery was diagnosed in two herds. The clinical history and postmortem findings were typical of Brachyspira hyodysenteriae infection. Co-infection with Salmonella  Reading was present on one unit.

Chronic ill thrift and colitis affected a batch of ten-week-old pigs causing four per cent mortality. The pigs submitted for postmortem examination were found to be infected by a combination of monophasic group B Salmonella species and Brachyspira pilosicoli. Exudative epidermitis due to Staphylococcus hyicus was also present in these pigs.

On an unrelated unit, a severe outbreak of exudative epidermitis was diagnosed in six-week-old pigs causing twenty per cent morbidity. Pigs submitted for postmortem examination had severe generalized scabbing and encrustation of the skin of the head, ears, trunk and limbs, with almost 100 per cent of the skin surface affected. Staphylococcus hyicus was isolated from skin lesions.