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Novel atypical Aeromonas salmonicida bath challenge model for juvenile ballan wrasse ( Labrus bergylta, Ascanius)
Author(s) -
Papadopoulou Athina,
Garvey Kathryn,
Hill Tom,
RamirezParedes Jose G.,
Monaghan Sean J.,
Baily Johanna L.,
Davie Andrew,
Katsiadaki Ioanna,
VernerJeffreys David,
Wallis Timothy,
Migaud Herve,
Adams Alexandra
Publication year - 2021
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.13312
Subject(s) - wrasse , biology , aeromonas salmonicida , vibrionaceae , microbiology and biotechnology , virulence , juvenile fish , virology , juvenile , outbreak , fishery , bacteria , fish <actinopterygii> , ecology , biochemistry , genetics , gene
Atypical Aeromonas salmonicida (a As ) is currently one of the most routinely recovered bacterial pathogens isolated during disease outbreaks in farmed cleaner fish, ballan wrasse ( Labrus bergylta , Ascanius). Vibrionaceae family bacteria have also been isolated from ballan wrasse in Scotland. This study determined the infectivity, pathogenicity and virulence of a As and Vibrionaceae isolates in juvenile farmed ballan wrasse ( n = 50; approx. 2 g) using a bath challenge, and fish were monitored for a period of 16 days. Atypical As caused significant mortalities in contrast to Vibrionaceae isolates. Notably, differential virulence was observed between two a As vapA type V strains at similar challenge doses. Diseased fish exhibited a systemic infection where a As was detected in all analysed tissues (liver, spleen and kidney) by PCR and qPCR. Macroscopically, moribund and survivor fish exhibited hepatomegaly and splenomegaly. In moribund and surviving fish, histopathology showed granulomatous hepatitis with eosinophilic granular cells surrounding bacterial colonies and endocarditis along with splenic histiocytosis. This is the first report of a successful a As bath challenge model for juvenile ballan wrasse which provides an important tool for future studies on vaccine efficacy and immunocompetence.