399
ated with disease. Originally, the organism was fi rst described as being a problem
on freshly landed halibut, on which it produced a yellowish slime (Harrison and
Sadler 1929 ). It would seem likely that the fi rst bona fi de report of fi sh pathogenic
fl avobacteria was by Bein ( 1954 ), who described Fla. piscicida as the causal agent
of mass mortalities (referred to as ‘red tide’) in marine fi sh from Florida,
USA. Incidence of the disease appeared to be associated with the proliferation of
phytoplankton and may, consequently, be considered as infl uenced by water quality.
The name of Fla. piscicida does not appear in the ‘Approved Lists of Bacterial
Names’ (Skerman et al. 1980 ) or their supplements, and is, therefore, of dubious
taxonomic standing.
A fi lamentous Gram-negative organism, isolated from gill lesions in rainbow
trout and Yamame salmon, formed the basis of an article by Kimura et al. ( 1978 ).
These isolates from Japan, together with similar strains recovered from Oregon,
USA, were included in a detailed investigation by Wakabayashi et al. ( 1980 ). The
outcome was recognition of a novel group of Flavobacterium, i.e. Fla. branchiophila (Wakabayashi et al. 1989 ). This name has now been corrected to Fla. branchiophilum (von Graevenitz 1990 ), and its authenticity verifi ed (Bernardet et al.
1996 ). Fla. branchiophilum appears to be spreading as a fi sh pathogen in the Far
East e.g. in Korea (Ko and Heo 1997 ).
There have been other reports of ‘fl avobacteriosis’ caused by unknown species of
Flavobacterium (e.g. Brisou et al. 1964 ; Roberts 1978 ; Acuigrup 1980 ; Farkas
1985 ). Whereas there has been reticence to equate these organisms with existing
nomenspecies (or to name new species), the descriptions of the aetiological agents
have been quite reasonable. For example, Acuigrup ( 1980 ) discussed fl avobacteriosis among coho salmon held in Spanish seawater sites. This disease, which resembled a generalised septicaemia, caused 20–25 % mortality in the fi sh population
during the summer of 1978. The subsequent description of the organism was superior to the initial work with Fla. balustinum or Fla. piscicida. Fla. succinicans has
been suggested as a fi sh pathogen (see Zamora et al. 2012b ) whereas Fla. chilense
and Fla. araucananum have been recovered from diseased salmonids in Chile but
pathogenicity has not been proven (Kämpfer et al. 2011 ). Similarly, Fla. collinsii ,
Fla. branchiarum and Fla. branchiicola have been found in and around the aquaculture environment, including fi sh gills and liver, but pathogenicity has not been
addressed (Zamora et al. 2013 ).
Cytophagas became implicated as fi sh pathogens with the work on coldwater
(low-temperature) disease. The causal agent was initially isolated and described by
Borg ( 1948 ), and subsequently named as Cyt. psychrophila (Borg 1960 ), and then
to Fla. psychrophilum (Bernardet et al. 1996 ). Coldwater disease affects predominantly juvenile salmonid fi sh, notably coho salmon in the northwest USA, and is
most prevalent in winter and spring when the water temperature is <10 °C. Cranial
and vertebral lesions may occur (Kent et al. 1989 ). More recently, the organism has
been associated with systemic disease in eels and cyprinids in Europe (Lehmann
et al. 1991 ) and with an anaemic condition of juvenile rainbow trout in Chile (Bustos
et al. 1995 ) and Europe (e.g. Lorenzen et al. 1991 ), referred to as rainbow trout fry
syndrome [RTFS] (Baudin-Laurençin et al. 1989 ; Lorenzen et al. 1991 ).
7 Flavobacteria and Cytophagas
ated with disease. Originally, the organism was fi rst described as being a problem
on freshly landed halibut, on which it produced a yellowish slime (Harrison and
Sadler 1929 ). It would seem likely that the fi rst bona fi de report of fi sh pathogenic
fl avobacteria was by Bein ( 1954 ), who described Fla. piscicida as the causal agent
of mass mortalities (referred to as ‘red tide’) in marine fi sh from Florida,
USA. Incidence of the disease appeared to be associated with the proliferation of
phytoplankton and may, consequently, be considered as infl uenced by water quality.
The name of Fla. piscicida does not appear in the ‘Approved Lists of Bacterial
Names’ (Skerman et al. 1980 ) or their supplements, and is, therefore, of dubious
taxonomic standing.
A fi lamentous Gram-negative organism, isolated from gill lesions in rainbow
trout and Yamame salmon, formed the basis of an article by Kimura et al. ( 1978 ).
These isolates from Japan, together with similar strains recovered from Oregon,
USA, were included in a detailed investigation by Wakabayashi et al. ( 1980 ). The
outcome was recognition of a novel group of Flavobacterium, i.e. Fla. branchiophila (Wakabayashi et al. 1989 ). This name has now been corrected to Fla. branchiophilum (von Graevenitz 1990 ), and its authenticity verifi ed (Bernardet et al.
1996 ). Fla. branchiophilum appears to be spreading as a fi sh pathogen in the Far
East e.g. in Korea (Ko and Heo 1997 ).
There have been other reports of ‘fl avobacteriosis’ caused by unknown species of
Flavobacterium (e.g. Brisou et al. 1964 ; Roberts 1978 ; Acuigrup 1980 ; Farkas
1985 ). Whereas there has been reticence to equate these organisms with existing
nomenspecies (or to name new species), the descriptions of the aetiological agents
have been quite reasonable. For example, Acuigrup ( 1980 ) discussed fl avobacteriosis among coho salmon held in Spanish seawater sites. This disease, which resembled a generalised septicaemia, caused 20–25 % mortality in the fi sh population
during the summer of 1978. The subsequent description of the organism was superior to the initial work with Fla. balustinum or Fla. piscicida. Fla. succinicans has
been suggested as a fi sh pathogen (see Zamora et al. 2012b ) whereas Fla. chilense
and Fla. araucananum have been recovered from diseased salmonids in Chile but
pathogenicity has not been proven (Kämpfer et al. 2011 ). Similarly, Fla. collinsii ,
Fla. branchiarum and Fla. branchiicola have been found in and around the aquaculture environment, including fi sh gills and liver, but pathogenicity has not been
addressed (Zamora et al. 2013 ).
Cytophagas became implicated as fi sh pathogens with the work on coldwater
(low-temperature) disease. The causal agent was initially isolated and described by
Borg ( 1948 ), and subsequently named as Cyt. psychrophila (Borg 1960 ), and then
to Fla. psychrophilum (Bernardet et al. 1996 ). Coldwater disease affects predominantly juvenile salmonid fi sh, notably coho salmon in the northwest USA, and is
most prevalent in winter and spring when the water temperature is <10 °C. Cranial
and vertebral lesions may occur (Kent et al. 1989 ). More recently, the organism has
been associated with systemic disease in eels and cyprinids in Europe (Lehmann
et al. 1991 ) and with an anaemic condition of juvenile rainbow trout in Chile (Bustos
et al. 1995 ) and Europe (e.g. Lorenzen et al. 1991 ), referred to as rainbow trout fry
syndrome [RTFS] (Baudin-Laurençin et al. 1989 ; Lorenzen et al. 1991 ).
7 Flavobacteria and Cytophagas