Establishment of different challenge models for Aeromonas salmonicida subsp. achromogenes in turbot and sole

Torres-Corral, Yolanda; González-Barreiro, Oscar; Riaza, Ana; Santos, Ysabel

Establishment of different challenge models for Aeromonas salmonicida subsp. achromogenes in turbot and sole

2022

Torres-Corral, Yolanda | González-Barreiro, Oscar | Riaza, Ana | Santos, Ysabel

Aeromonas salmonicida subsp. achromogenes is one of the causative agents of “atypical furunculosis”, characterized by the presence of dermal ulcerations and external pathology with or without subsequent septicaemia. This study was aimed to identify possible routes of infection of A. salmonicida subsp. achromogenes in turbot (Scophthalmus maximus) and sole (Solea senegalensis). Thus, challenge tests were performed using four different infection routes: intraperitoneal (ip), and subcutaneous (sc) injection, immersion (im) and intragastric (ig) inoculation. Among the inoculation routes tested ip and sc injection and im caused mortality and reproduced the clinical signs of the furunculosis in the experimentally infected fish. The strains of A. salmonicida subsp. achromogenes used in this study showed no host specificity, being capable of infecting turbot and sole in experimental conditions reaching 80–100% of mortality after ip and sc inoculation. A. salmonicida subsp. achromogenes was confirmed as the causative agent of mortalities by culture and qPCR analysis of samples from moribund or dead fish. Further studies are needed to identify route of entry and dissemination of A. salmonicida subsp. achromogenes in fish which will help to improve treatment and prophylactic strategies.

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