EN
In one of the largest pig farm (3000 sows), many cases of sickness and deaths (10%) were found in young pigs. Main symptoms of the disease were observed in the respiratory tract. On post-mortem examination the following lesions were found in the thorax: fibrinous pleuritis and large quantity of serous and bloody pleural effusion containing fibrinoid elements. In more chronic cases, pulmonal abscesses and adhesions between the parietal and pulmonal pleura and pericardium were observed. Bacteriological examinations of samples taken from pathological lesions in the lung tissue of dead and killed pigs revealed the presence of Actinobacillus pleuropneumoniae in a pure culture. These pathogenes were classified into serotype 9 by the coagglutination test. Clinical, bacteriological and post-mortem examinations showed that the cause of health problems in this farm was pleuropneumonia induced by Actinobacillus pleuropneumoniae, serotype 9.