[Demonstration of pneumonia in swine as a constant problem: culture and immunofluorescence microscopic studies of bronchioalveolar lavage (BAL) and serological findings].

Bronchoalveolar lavage was performed in 128 pigs from five fattening units showing acute pneumonia (48 animals), subclinical purulent pneumonia (17 animals), and chronic purulent pneumonia (63 animals). These samples were investigated for bacteria. Additionally immunofluorescence microscopy as well as serological investigations were performed to detect antibodies against several bacteria and viruses. Pasteurella multocida could be detected in more than a half of the samples of pigs with acute pneumonia. Bordetella bronchiseptica and mycoplasmas were isolated in a lower amount. Probably these bacteria infected the pigs of at least one herd after a primary infection with influenza virus because (i) influenza virus could be detected in three of four animals investigated for influenza virus by culture methods, (ii) the virus could be detected in one third of the animals investigated for by immunofluorescence microscopy, and (iii) antibodies against influenza virus could be detected in almost all animals. From pigs with subclinical purulent pneumonia Bordetella bronchiseptica as the only bacterial lung pathogen could be isolated exclusively from nearly each sample. From the samples of pig suffering from chronic purulent pneumonia first of all Bordetella bronchiseptica, Pasteurella multocida and different mycoplasma species could be detected. Using cultural methods Actinobacillus pleuropneumoniae could be isolated from six samples only, in contrast to frequent positive reactions against Actinobacillus pleuropneumoniae antigens obtained by immunofluorescence microscopy and CFT.