Occurrence of pleurisy in fattening pigs in three different epidemiological regions in Germany

Monitoring lung lesions at slaughter can be an efficient tool in estimating the prevalence and severity of respiratory diseases in fattening pigs. Actinobacillus pleuropneumoniae (App) can be associated with chronic pleurisy. German pig production can be characterized by the existence of three different epidemiological regions: Northern Germany with high pig density; Eastern Germany with fewer but larger farms and in contrast to that Southern Germany with smaller farms. The present study was conducted to estimate the appearance of pleurisy in Germany under respect of the APP serotypes on farm level.

In total 49 fattening farms (North: 20; East: 9; South: 20) with recurring respiratory disease were included in the present study. In total 4723 lungs (appr. 100 lungs per farm) were examined for the occurrence of pleurisy at slaughter. Location and extension of pleurisy was evaluated by the Slaughterhouse Pleurisy Evaluation System (SPES). SPES values from 2 to 4 qualify increased severity of dorsocaudal pleurisy. Blood samples were collected within 4 weeks after slaughterhouse checks (20/farm; in total 980) and tested for antibodies against App; 5 seropositive samples per farm (in total 204) were further serotyped.

Pleurisy was evident in 2153 (45.6 %) of all examined lungs. In Northern Germany (a) pleurisy was found significantly more frequently (60.7 %) than in Eastern Germany (b; 35.7 %) and in Southern Germany (c; 34.7%) (ab; ac:p< 0.001). Furthermore, in Northern Germany occurrence of pleurisy grades SPES 2 and SPES 3 was significantly higher than in Eastern and Southern Germany (ab; ac:p< 0.001). The occurrence of SPES 4 was equally distributed among the regions. Farms positive for App serotype (ST) 2 had a 4 times higher (OR=3.98; p< 0.001) risk to suffer from pleurisy. Moreover, the occurrence of further App-serotypes increased the risk for pleurisy: ST 3/6/8 (OR= 2.36); ST 10 (OR=1.82); ST 5 (OR=1.62); ST 1/9/11 (OR=1.26) (p< 0.001). Occurrence of antibodies against ST 12 and 4/7 on farm level did not increase the risk for pleurisy.

Pleurisy is highly prevalent in German fattening pigs with recurring respiratory disease. The frequency of pleurisy seems to depend on the regions where pigs are housed. Farms serologically positive for App ST 2, ST 3/6/8 and ST 10 showed a significantly increased risk to suffer from pleurisy.

Disclosure of Interest: None Declared.