Natural Bacterial Co-Infection in Farmed European Sea Bass Intended for Experimental Research in Sicily, Southern Italy: Pathological Findings
Simone Palazzolo,
Claudio Gervasi,
Jessica Maria Abbate,
Emil Gjurčević,
Rosa Falleti,
Maria Giovanna Piro,
Giovanni Lanteri,
Carmelo Iaria,
Fabio Marino
Affiliations
Simone Palazzolo
University School for Advanced Studies IUSS Pavia, Palazzo del Broletto, Piazza della Vittoria 15, 27100 Pavia, Italy
Claudio Gervasi
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Jessica Maria Abbate
Department of Veterinary Sciences, University of Messina, Polo Universitario Annunziata, 98168 Messina, Italy
Emil Gjurčević
Department for Biology and Pathology of Fishes and Bees, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia
Rosa Falleti
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Maria Giovanna Piro
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Giovanni Lanteri
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Carmelo Iaria
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
Fabio Marino
Institute for Comparative, Experimental, Forensic and Aquatic Pathology (ICEFAP) “Slavko Bambir”, Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale F. Stagno D’Alcontres 31, 98166 Messina, Italy
In mariculture facilities, bacterial infections pose significant production challenges, with potentially catastrophic impacts on fish species. Bacterial co-infections are a widespread phenomenon in the natural marine environment, although their impact on aquatic organisms remains poorly investigated. This study aimed to detail the pathological findings associated with a natural bacterial co-infection caused by three different pathogens, namely Photobacterium damselae subsp. piscicida, Tenacibaculum maritimum and Vibrio sp., as the cause of mass mortality in European sea bass. The fish had been reared in open-net cages in Sicily and later transferred for experimental research purposes to a user establishment after immunization with an inactivated vaccine. Macroscopic, cytological and histopathological examinations were performed on 109 animals, and bacterial species were identified by the 16S rRNA gene. Overall, ulcerative skin lesions, necrotizing myositis and tail rot with occasional tail loss were associated with tenacibaculosis and vibriosis, while P. damselae subsp. piscicida mainly caused granulomatous inflammation in the spleen and head kidney. Finally, an injection site reaction due to the oil-adjuvanted vaccine administered intraperitoneally was observed in the abdominal fat. Understanding the impact of bacterial pathogens is essential to manage the health and welfare of farmed fish, and the importance of a good health monitoring program cannot be overstated to avoid outbreaks and the possible emergence of new pathogens due to the intensification of the production systems, antibiotic resistance and climate changes. The study would also highlight the importance of the quarantine period when animals supplied for research come from aquaculture farms and how the main goal in the near future should be to better define the procedures to provide completely pathogen-free animals.
