Serological characterization of Actinobacillus pleuropneumoniae strains and proposal of a new serotype: serotype 12

Until now 11 serotypes of Actinobacillus pleuropneumoniae have been described (Nicolet 1971, Gunnarsson 1980, Nielsen 1982, Rosendal & Boyd 1982, Nielsen & O’Connor 1984, Nielsen 1985, Kamp 1986). Recently a hitherto unrecognized serotype was isolated from 9 Danish outbreaks of pleuropneumonia in pigs. The origin of the strains is given in Table 1. From 3 herds the unrecognized serotype was found in 2 to 3 pigs submitted for necropsy at different times. The present study describes the serological properties of the 13 isolated strains.