Title:Actinobacillus pleuropneumoniae okozta heveny megbetegedés egy hónapos malacokban Esetismertetés
SUMMARY Background: Actinobacillus pleuropneumoniae is an important pathogen of swine, it can cause respiratory disease in piglets sometimes from 6 weeks of age, but typically 12-16 week-old feeder pigs are susceptible. It has two biotypes and 16 serotypes, and due to the different pattern of toxin production there are great differences in the virulence of the strains. Objectives: Besides reaching etiologic diagnosis, the objective of the examina tion was to prove that in case of special circumstances sometimes young pig lets around weaning age can show the clinical signs and post mortem lesions caused by Actinobacillus pleuropneumoniae. Materials and methods: Lungs of six 28 and 31-day-old piglets showing lesions of acute haemorrhagic-necrotic pneumonia and fibrinous pleuritis were sent from a large scale farm with 3000 sows in the Eastern part of Hungary. According to our previous examinations A. pleuropneumoniae was present in the herd; serotype 16 strains were isolated earlier but the pigs in the farm were not vaccinated against A. pleuropneumoniae. The lung samples were inoculated on blood agar plates; they were cross-inoculated with Staphylococcus aureus and incubated at 37 ºC for 24 hours in the presence of 5% carbon dioxide. The isolated A. pleuropneumoniae strains were serotyped using the indirect haemagglutination test. Results and Discussion: Actinobacillus pleuropneumoniae biotype 1 serotype 11 strains were isolated from the lungs; this serotype was not detected in this farm earlier. The examinations confirmed that A. pleuropneumoniae can cause disease not only in grower and feeder pigs, but a newly introduced serotype can also result severe clinical signs and lesions of the disease around weaning in the absence of maternal protection. The age of the diseased animals can be informative in setting up the diagnosis of an infectious disease; however the circumstances have to be always carefully evaluated.