Seroprevalence of Actinobacillus pleuropneumoniae infection in pigs from Bulgaria

Actinobacillus pleuropneumoniae (App) is the etiological agent of porcine pleuropneumonia. The purpose of the study was to present a serological report on App prevalence among pigs in industrial farms in Bulgaria. Seventy-two pigs from four industrial farms in four districts of Bulgaria – Eastern Bulgaria (Razgrad and Yambol districts) and Western Bulgaria (Lovech and Sofia districts) were included. Animals were divided in two age groups: weaners and fattening pigs. A commercial enzyme-linked immunosorbent assay (ELISA, INgezim APP MIX, Eurofins Ingenasa, Madrid, Spain) for the detection of antibodies against App parasuis in porcine serum was used. Microtitrе plate was coated with App antigen of the serovars 1, 2, 9 and 11. Positive results for anti-App antibodies were detected in 32 (44.4%) of all 72 tested sera. The overall seropositivity in weaners and fattening pigs was 22.2% (8/36), and 66.7% (24/36), respectively. The highest App seropositivity in pigs was found in Eastern Bulgaria - 61.1% (22/36; P<0.001) in comparison to App seropositivity in Western Bulgaria – 27.8% (10/36; P=0.137). This study on anti-App prevalence among pigs in Bulgaria gives new insights on App epidemiology in our country.