[Influenza epizootic in swine due to strain A (Victoria/3/75 H3N2)]

Studies were carried out on the first grippe epizootic in pigs in Bulgaria. The affected animals showed a rise in temperature (40.5 to 41.8 degrees C), loss of appetite, abdominal type of respiration, and noisy and painful cough. The infection ran its course with a picture typical of a virus disease which did not respond to broad-spectrum antibiotic treatment. On an average the duration of the clinical course lasted 4 to 5 days, affecting almost all swine on a pig breeding farm, with single death cases. The morphologic changes observed in animals killed for diagnostic purposes were typical of a grippe infection. Isolated was a grippe virus A (Antimovo) 1/80/H3N2) the preliminary typisation of which showed close relation to strain A (victoria) 3/75/H3N2/. Serologic investigations using double blood samples from the affected pigs in double immunodiffusion test and hemagglutination-inhibition test demonstrated the etiologic role played by the isolated grippe virus.