Health status of two salmonid aquaculture facilities in North Portugal: Characterization of the bacterial and viral pathogens causing notifiable diseases

• Type: Article in International Scientific Journal
• Date: 1996

Authors

Sousa, JA (Author) FCUP; Romalde, JL (Author) Other; Ledo, A (Author) Other; Eiras, JC (Author) FCUP; Barja, JL (Author) Other; Toranzo, AE (Author) Other

Journal

Title: Journal of Fish Diseases

Vol. 19

Pages: 83-89

ISSN: 0140-7775

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 16 Citations

Other information

Authenticus ID: P-001-FC8

DOI: 10.1111/j.1365-2761.1996.tb00123.x

Abstract (EN): A comparative bacteriological and virological survey was conducted in two fish farms in the North of Portugal. The fish species examined included cultured rainbow trout, Oncorhynchus mykiss (Walbaum), and brown trout, Salmo trutta L., as well as wild fish captured near both facilities. The microbial load in the internal organs of apparently healthy fish was monitored over a year, and all the disease problems occurring during this period were investigated. Although both farms presented intermediate levels of infection (30-40% infected fish), farm B showed the poorest microbiological quality since constant but low mortalities were observed throughout the year. Flavobacterium and Pseudomonas-Xanthomonas were the predominant bacterial groups, comprising around 40-50% of the isolates from each farm. In farm B, members of the Enterobacteriaceae and motile Aeromonas also showed significant prevalence (about 20%). The only outbreak of a notifiable disease was an occurrence of furunculosis, caused by Aeromonas salmonicida subsp. salmonicida, in farm A. However, Yersinia ruckeri was isolated not only from diseased fish, but also from asymptomatic fish, usually in mixed infections with motile Aeromonas or infectious pancreatic necrosis virus (IPNV). While Y. ruckeri isolates associated with mortalities belonged to the serotype O1 (subgroup a), those isolated from asymptomatic fish corresponded to serotype O3. Two strains of IPNV (serotype Ab) were isolated in farm B, which represents the first viral agent detected in Portuguese aquaculture. Qualitative and quantitative differences in microbial load were observed between cultured and wild fish. No notifiable bacterial or viral pathogens were detected in any of the feral species studied.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7