[Direct detection of Actinobacillus (Haemophilus) pleuropneumoniae in the lungs of swine].

By means of cultural examination, coagglutination test (CT) and indirect fluorescent-antibody-technique (IFAT) a total of 199 lung specimens from necropsy pigs from Northwestern Germany with symptoms of pleuropneumonia was examined for Actinobacillus (Haemophilus) pleuropneumoniae (AP). The CT was used to detect type specific antigens in lung extracts and the IFAT was performed on tissue sections. Both tests were found to be specific. Detection and identification of AP by either test were successful in 68 of 199 lung specimens. AP was isolated out of 40 lungs, antigen detection by CT was successful in 40 and by IFAT in 65 lung samples. In 26.5% of the positive samples AP was demonstrated only by IFAT. In 4.4% of the positive specimens AP was demonstrated only by cultural examination, but the detected serovars were not accounted in IFAT and CT. In 44.1% of the positive specimens AP was isolated or detected by all three techniques. The predominating serovar was serovar 9 followed by 2 and 7. One field isolate could be identified as serovar 3 and another one as serovar 10. Furthermore one isolate was untypable. IFAT and CT were limited for detection of serovars 2, 7 and 9. Detection of multiple serovars in few lung samples was successful only by IFAT. Indirect fluorescent-antibody-technique was found to be more sensitive than coagglutination test and cultural examination. On the other hand CT was found to be less time consuming and easier to evaluate than other tests. By this, coagglutination test seems to be preferable in examining large numbers of lung samples.