A study of lesions induced in Seriola dumerili infected naturally with Streptococcus dysgalactiae

An outbreak of disease in Seriola dumerili occurred from August to October in 2007 and 2008. The fish developed lesions of the caudal peduncle, pectoral and/or dorsal fin and the heart. The lesions were characterized by moderate to severe infarction with areas of microabscessation and multifocal granulomatous inflammation associated with the presence of Streptococcus dysgalactiae antigen. This is the first report to describe the immunohistology of the lesions induced in S. dumerili following natural infection with S. dysgalactiae.