Title:Az Actinobacillus pleuropneumoniae 16-os szerotípusa által okozott légzőszervi megbetegedés tapasztalatai egy sertéstelepen
Summary Background: Pleuropneumonia with high economic losses caused by Actino bacillus pleuropneumoniae is common throughout the world. A. pleuropneumo niae has two biotypes and 16 serotypes. Serotype 16 was described recently in Hungary and it has not been isolated from other countries yet. Genes for the production (apxIA) and secretion (apxIB) of ApxI, the gene for the expression of ApxII and apxIV gene were detected in it. Objectives: Serotype 16 of A. pleuropneumoniae was diagnosed in a large scale pig herd with 1350 sows in the Eastern part of Hungary in acute cases of pleuro pneumonia. On the basis of the bacteriological examinations the formerly used marketed, registered vaccine produced from inactivated A. pleuropneumoniae strains was replaced with a marketed and registered vaccine containing inacti vated toxins of A. pleuropneumoniae and outer membrane protein in standardi zed amount. The objective was to evaluate its protective effect. Materials and methods: Four lungs of dead pigs and four lungs collected at the slaughterhouse, showing lesions of acute haemorrhagic-necrotic pneumonia and fibrinous pleuritis were sent to the laboratory. After changing the vaccine, a few months later 14 lungs with chronic pleuropneumonia were examined. The isolated A. pleuropneumoniae strains were serotyped using the indirect haem agglutination test. Results: Serotype 16 of A. pleuropneumoniae was isolated from all the 8 acute and 14 chronic forms. In that part of the herd where the animals were inject ed with the toxoid vaccine (only healthy animals were vaccinated), the acute respiratory signs have not been seen any more, however A. pleuropneumoniae serotype 16 strains could be still isolated from lung samples collected at the slaughterhouse from animals having chronic lesions.