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On-line version ISSN 1678-4596
SOUZA, Karina Koerich de et al. Polymerase Chain Reaction (PCR) based on the cpx gene for detection of Actinobacillus pleuropneumoniae in natural and experimentally infected pigs. Cienc. Rural [online]. 2008, vol.38, n.7, pp. 1954-1960. ISSN 1678-4596. http://dx.doi.org/10.1590/S0103-84782008000700024.
Swine pleuropneumonia is one of the most important pig respiratory diseases and has been found in all producer countries. For control and monitoring of pleuropneumonia, it is necessary the development of fast and specific methods of diagnosis. To validate PCR based on the cpx gene of Actinobacillus pleuropneumoniae in positive pigs, an experimental infection with A. pleuropneumoniae serotype 5B was performed and samples were obtained by tonsil swab, tonsil biopsy and blood for PCR, bacterial isolation and ELISA, respectively. These tests were then performed in naturally infected pigs from three herds with different sanitary situations of clinical disease. In each herd, five groups of different ages were analyzed. Tonsil biopsy for bacterial isolation and PCR and blood to determine the herd serological status was collected. The results obtained in the experimental infection confirmed that, even with the infection establishment, proved with bacterial isolation, it was not possible to detect the agent by PCR 45 days after infection. In naturally infected animals, PCR was more sensitive than bacterial isolation. The association between PCR and ELISA is a good alternative to define the herd sanitary status regarding the infection with A. pleuropneumoniae.
Keywords : swine; Actinobacillus pleuropneumoniae; PCR; diagnostic; cpx gene.