The prevalence of lung lesions in pigs at slaughter in Switzerland.

A survey of the prevalence of lung lesions in randomly selected slaughtered swine representative of the Swiss fattening pig population was carried out from May to September 1992 in six large abattoirs. In total 8921 lungs out of 561 herds were examined. Histological investigations were completed in every herd. No gross lesions could be found in 56% of the pigs. The most frequent lesions in individuals were bronchopneumonia (21%) and diffuse pleuritis (21%). Linear scars (9%), focal pleural fibrosis without any pneumonic lesion (2%), pleuropneumonia (1%) and abscesses (1%) were less prevalent. The prevalence of lesions at the herd level was completely different. The lungs of only 14% of the herds were free of any lesions. The main finding at the herd level was a diffuse pleuritis (75%), followed by bronchopneumonia (64%), linear scars (60%), focal pleural fibrosis (20%), abscesses (14%) and pleuropneumonia (9%). In 94% of the herd samples with macroscopically diagnosed bronchopneumonia, the histological lesions were consistent with enzootic pneumonia of pigs.