title: Adherence of Flavobacterium psychrophilum on the body surface of the ayu Plecoglossus altivelis.
abstract: Bacterial cold water disease in the ayu Plecoglossus altivelis caused by Flavobacterium psychrophilum is a serious problem in the Japanese freshwater culture industry. The distribution and activity of this bacterium on the body surface of the ayu in the infection process was investigated. The survival of F. psychrophilum in tap water showed that this bacterium might sustain its infectivity for 24 h. In an experimental infection, juvenile ayu were immersed in water containing 10(8.9) CFU/ml F. psychrophilum, and the progressing infection was followed by scanning electron microscopy during a 24-h period. This bacterium was observed in the ayu for 24 h adhering to the lower jaw and caudal peduncle, where the epidermis tissue was collapsed. This study showed that bacterial suspension in water sustains the activity of this bacterium. F. psychrophilum attaches especially to the jaw and caudal peduncle, growing at these sites, collapsing the dermal structure and invading the tissues.
authors.affiliation: Fish Disease Laboratory, Department of Aquaculture, Kochi University, Nankoku, Kochi 783-8502, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Kondo
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawai
authors.forename: Kenrou
authors.initials: K
authors.lastname: Kurohara
authors.forename: Syun-ichirou
authors.initials: S
authors.lastname: Oshima
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D005393:Fish Diseases / Q000382:microbiology* / Q000473:pathology; D005417:Flavobacterium / Q000166:cytology / Q000472:pathogenicity* / Q000648:ultrastructure; D017858:Salmoniformes / Q000033:anatomy & histology / Q000254:growth & development / Q000382:microbiology*; D014871:Water Microbiology