355
It should be emphasised that phylogenetic studies have indicated that the taxon
should really belong in the genus Proteus as Proteus shigelloides (MacDonell et al.
1986 ).
Pathogenicity
At 10
5 CFU/ml, an isolate caused 100 % mortalities of cichlids within 48 h (Nisha
et al. 2014 ).
Epizootiology
The outbreak in 1984 affected mostly 1–2 year old fi sh, in which the total mortality
approximated 40 % of the population. There was a correlation with water temperature, which increased in June from 10 to 17 °C. Moreover, there was a pronounced
increase in organic matter from food within the water. These factors would undoubtedly contribute to stress in the fi sh. It has been noted that P. shigelloides may be
normally resident in the gastro-intestinal tract of warm-water fi sh (Vandepitte et al.
1980 ), from where it could serve as a reservoir of infection.
Disease Control
Antimicrobial Compounds A 10-day treatment regime with potentiated sulphonamides (sulphadiazine at 200 mg/kg of body weight of fi sh/day and trimethoprim at
50 mg/kg body weight of fi sh/day) was effective in reducing mortality levels (Cruz
et al. 1986 ).
Providencia rettgeri
Characteristics of the Disease
During 1976, there was a mass mortality among farmed silver carp
( Hypophthalmichthys molitrix ) in Israel. The fi sh displayed large red ulcers on the
abdomen, base of the pectoral fi n, and around the head. At 20–23 °C, mortalities
occurred in 3 days, whereas at 12–20 °C, the deaths ensued in 8 days (Bejerano
et al. 1979 ).
Providencia rettgeri
It should be emphasised that phylogenetic studies have indicated that the taxon
should really belong in the genus Proteus as Proteus shigelloides (MacDonell et al.
1986 ).
Pathogenicity
At 10
5 CFU/ml, an isolate caused 100 % mortalities of cichlids within 48 h (Nisha
et al. 2014 ).
Epizootiology
The outbreak in 1984 affected mostly 1–2 year old fi sh, in which the total mortality
approximated 40 % of the population. There was a correlation with water temperature, which increased in June from 10 to 17 °C. Moreover, there was a pronounced
increase in organic matter from food within the water. These factors would undoubtedly contribute to stress in the fi sh. It has been noted that P. shigelloides may be
normally resident in the gastro-intestinal tract of warm-water fi sh (Vandepitte et al.
1980 ), from where it could serve as a reservoir of infection.
Disease Control
Antimicrobial Compounds A 10-day treatment regime with potentiated sulphonamides (sulphadiazine at 200 mg/kg of body weight of fi sh/day and trimethoprim at
50 mg/kg body weight of fi sh/day) was effective in reducing mortality levels (Cruz
et al. 1986 ).
Providencia rettgeri
Characteristics of the Disease
During 1976, there was a mass mortality among farmed silver carp
( Hypophthalmichthys molitrix ) in Israel. The fi sh displayed large red ulcers on the
abdomen, base of the pectoral fi n, and around the head. At 20–23 °C, mortalities
occurred in 3 days, whereas at 12–20 °C, the deaths ensued in 8 days (Bejerano
et al. 1979 ).
Providencia rettgeri