409
Diagnosis
Serology Rapid identifi cation of Fla. branchiophilum was achieved by ELISA,
which detected 1 × 10
3 cells/ml from gills [= the threshold value] (MacPhee et al.
1995 ).
Molecular Methods PCR targeted 16S rRNA has been successful with recognising Fla. branchiophilum, Fla. columnare and T. maritimum (Toyama et al.
1994 , 1996 ; Avendaño-Herrera et al. 2004e ; Yeh et al. 2006 ). Similarly, a DNA
array- based multiplex assay permitted the simultaneous specifi c and sensitive
(<1 pg of bacterial DNA) recognition and identifi cation/differentiation of Fla.
branchiophilum, Fla. columnare and Fla. psychrophilum , and viruses (Lievens
et al. 2011 ).
Epizootiology
Fla. branchiophilum may be fatal to small fi sh following infection via water, i.e.
adding a bacterial suspension to tank water (Wakabayashi et al. 1980 ). Certainly, the
pathogen is present in water at times of disease outbreaks (Heo et al. 1990 ).
Pathogenicity
Kimura et al. ( 1978 ) established that fatal infections by Fla. branchiophilum
were only induced following water-borne challenge in salmonids weighing
≤1.1 g each. Pathogenicity experiments with juvenile rainbow trout demonstrated that the organism occurred abundantly in the gills within 18–24 h after
exposure to a dilute bacterial suspension, i.e. 10–20 ml of a 48 h broth culture in
2 l of fresh water. The gill lamellae became very swollen, but the reasons for
subsequent fatalities remain unknown (Wakabayashi et al. 1980 ). Initial attachment of the pathogen to host cells may be by means of pili (Heo et al. 1990 ).
Scrutiny of the complete genome sequence revealed adhesins and a cholera-like
toxin; the fi rst time that this has been found in non- Proteobacteria (Touchon
et al. 2011 ).
Flavobacterium branchiophilum
Diagnosis
Serology Rapid identifi cation of Fla. branchiophilum was achieved by ELISA,
which detected 1 × 10
3 cells/ml from gills [= the threshold value] (MacPhee et al.
1995 ).
Molecular Methods PCR targeted 16S rRNA has been successful with recognising Fla. branchiophilum, Fla. columnare and T. maritimum (Toyama et al.
1994 , 1996 ; Avendaño-Herrera et al. 2004e ; Yeh et al. 2006 ). Similarly, a DNA
array- based multiplex assay permitted the simultaneous specifi c and sensitive
(<1 pg of bacterial DNA) recognition and identifi cation/differentiation of Fla.
branchiophilum, Fla. columnare and Fla. psychrophilum , and viruses (Lievens
et al. 2011 ).
Epizootiology
Fla. branchiophilum may be fatal to small fi sh following infection via water, i.e.
adding a bacterial suspension to tank water (Wakabayashi et al. 1980 ). Certainly, the
pathogen is present in water at times of disease outbreaks (Heo et al. 1990 ).
Pathogenicity
Kimura et al. ( 1978 ) established that fatal infections by Fla. branchiophilum
were only induced following water-borne challenge in salmonids weighing
≤1.1 g each. Pathogenicity experiments with juvenile rainbow trout demonstrated that the organism occurred abundantly in the gills within 18–24 h after
exposure to a dilute bacterial suspension, i.e. 10–20 ml of a 48 h broth culture in
2 l of fresh water. The gill lamellae became very swollen, but the reasons for
subsequent fatalities remain unknown (Wakabayashi et al. 1980 ). Initial attachment of the pathogen to host cells may be by means of pili (Heo et al. 1990 ).
Scrutiny of the complete genome sequence revealed adhesins and a cholera-like
toxin; the fi rst time that this has been found in non- Proteobacteria (Touchon
et al. 2011 ).
Flavobacterium branchiophilum