Reproductive diseases

Bury investigated a reproductive problem affecting a 400-sow outdoor breeding herd which had experienced an increase in sows found not-in-pig and also sows with irregular (28 day) returns to service. Eight of 18 sows were seropositive to Leptospira Bratislava. Kidneys and genital tract from a gilt with a high titre (1/800) were collected for Leptospira Bratislava culture and PCR as part of a national project.

Enteric diseases

Thirsk isolated Salmonella Typhimurium Phage Type 193 from seven-weekold pigs submitted for post-mortem examination. Three hundred out of 1200 had diarrhoea, ill thrift and cyanosis. Sixty had died. All three examined had necrotic colitis and typhilitis. In another case investigated Beta haemolytic E. coli 0149:K91,F4ac (Abbotstown) was isolated from gut contents submitted from a pig farm where about 24% of a group of 980 post-weaned pigs had been affected with diarrhoea and dehydration. Mortality was about 2%. Salmonella Kedougou was also isolated from the gut contents. It is thought that this salmonella was an incidental finding and only played a secondary role in the problem.

Respiratory Diseases: Actinobacillus pleuropneumoniae

Actinobacillus pleuropneumoniae infection was diagnosed by Bury on two multisource finishing units sharing a common pig source. Outbreaks of respiratory disease occurred with rapid death of affected pigs. The same source pigs on both units showed the highest mortality; on one unit 63 of 700 pigs were affected, and on the other unit 35 of 550 pigs were affected from this single source. There was much less disease in pigs from other sources. Disease occurred after pigs had been on the unit, apparently healthy, for four weeks. Three dead pigs were submitted.

All three pigs had widespread cranioventral lung consolidation, with well-demarcated areas of pulmonary necrosis or haemorrhage in two of the pigs, and pleurisy in one pig. Pasteurella multocida and Actinobacillus pleuropneumoniae were isolated. One of the pigs also had kidney lesions suggestive of PDNS, which was confirmed histopathologically, and there was histopathological evidence of resolving PMWS lesions.

Swine Influenza

Bury carried out an investigation into rising mortality in finishing pigs on a 300- sow breeder finisher unit. Mortality of approximately 15% from weaning to finishing had been experienced for the last 18 months with approximately half of these deaths occurring in the finishing stage. Much of the mortality was due to PDNS with some cases starting at the 16-week stage. A rise in mortality in January to 19% prompted a number of carcase submissions for investigations. The predominant findings were of PDNS and in two carcase submissions gross pathology suggested viral pneumonia. Swine influenza virus, strain H1N2, was isolated. The further rise in mortality appeared to be due to an outbreak of swine influenza. It is not known what, if any, effect this virus is having on mortality due to PDNS.

The carcase of a nine to ten week old fattening pig was received at Thirsk to investigate sudden onset pneumonia within the group. The gross postmortem was suspicious of a viral aetiology and virus isolation resulted in the identification of an H1 influenza virus similar to H1N2. The history was that the gilts and young sows, as well as two young boars, appeared off-colour. The gilts seemed to be farrowing slightly early but the piglets appeared normal. Dyspnoea was evident with a slight cough present in the adults. Some cough had been noted in the four to eleven week old weaners, which was worse in groups which had been moved.

Neurological Diseases: Meningitis