Virulence and Persistence of Rough and Smooth Forms of Aeromonas salmonicida Inoculated into Coho Salmon (Oncorhynchus kisutch)

1972 ◽  
Vol 29 (2) ◽  
pp. 204-206 ◽  
Author(s):  
Douglas P. Anderson

Virulent isolates of Aeromonas salmonicida showed a majority of smooth colonies, while the attenuated isolates displayed mostly rough colonies. A lesion occurred at the site of inoculation when one of the rough forms was inoculated into yearling coho salmon, but few mortalities were recorded even though the rough forms were readily recovered from both the lesion and the kidney. The fish inoculated with the same dosage of smooth forms all died within 96 hr of inoculation.

1974 ◽  
Vol 31 (11) ◽  
pp. 1743-1749 ◽  
Author(s):  
W. D. Paterson ◽  
J. L. Fryer

Specific antibody production in response to an intraperitoneal injection of A. salmonicida endotoxin first occurred in juvenile coho salmon (Oncorhynchus kisutch) held at 6.7, 12.2, and 17.8 C at 4, 2 and 1 wk, respectively. Aeromonas salmonicida endotoxin was antigenic to juvenile coho salmon at all doses between 1 and 5000 μg administered intraperitoneally with and without an aluminum hydroxide carrier.The endotoxin was nontoxic to juvenile coho salmon when 1–5000 μg was injected intraperitoneally and the fish held at temperatures from 6.7 to 17.8 C or when "free endotoxin" was administered by the intramuscular or intraperitoneal route. Aeromonas salmonicida endotoxin was toxic to mice, however.


1977 ◽  
Vol 34 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Ross Antipa ◽  
Donald F. Amend

Two methods of immunizing fish, intraperitoneal (i.p.) injection and hyperosmotic infiltration, were compared for control of vibriosis and furunculosis in pen-reared coho salmon (Oncorhynchus kisutch) and chinook salmon (O. tshawytscha). Both methods provided significant protection against vibriosis under field test conditions. In coho salmon, hyperosmotic infiltration provided the best protection and fastest rise in antibody titer of seven treatments tested. In chinook salmon, hyperosmotic infiltration of Vibrio anguillarum and Aeromonas salmonicida vaccines resulted in 83.3% survival in comparison with 28.7% survival in controls. Both i.p. injection and hyperosmotic infiltration of V. anguillarum and A. salmonicida bacterins resulted in production of serum antibodies specific for each respective pathogen. Vaccination with bivalent V. anguillarum–A. salmonicida vaccines produced antibodies to both pathogens, and provided protection against vibriosis. Growth rates of vaccinated coho salmon were not significantly different from controls.


1978 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
W. J. Groberg Jr. ◽  
R. H. McCoy ◽  
K. S. Pilcher ◽  
J. L. Fryer

Juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (O. tshawytscha) were infected by intraperitoneal or intramuscular injection with Aeromonas salmonicida or A. hydrophila at seven temperatures from 3.9 to 20.5 °C. At 3.9 and 6.7 °C, mortality in fish infected with A. salmonicida varied from 2 to 26% among the three salmonid species. At 20.5 °C 93–100% of these animals died within 2 or 3 days; at 6.7 °C or lower the fish survived for 12–23 days. Growth of A. salmonicida in vitro was influenced by temperature in a manner very similar to its influence on the in vivo infection. Comparable experiments with A. hydrophila gave results much like those with A. salmonicida, though some differences were noted. At a temperature of 20.5 °C percent mortality ranged from 64 to 100%. At 9.4 °C or below no deaths attributed to A. hydrophila occurred. Fatally infected fish died more rapidly at the higher temperatures. Key words: Aeromonas salmonicida, A. hydrophila, water temperature, furunculosis, motile aeromonas septicemia, coho salmon, chinook salmon, steelhead trout


1974 ◽  
Vol 31 (11) ◽  
pp. 1751-1755 ◽  
Author(s):  
W. D. Paterson ◽  
J. L. Fryer

The antibody response of a population of juvenile coho salmon (Oncorhynchus kisutch) held at 12 C approached 100% following a single parenteral vaccination with Aeromonas salmonicida cells emulsified in Freund's complete adjuvant. This response indicates that coho salmon behave as a homogeneous population with respect to immunological competence.Fish as small as 1.2 g produced antibodies as early as 4 wk after administration of this vaccine; high levels of antibody persisted for at least 1 yr after injection. This single vaccination provided juvenile coho salmon with protective immunity against furunculosis.


2004 ◽  
Vol 39 (3) ◽  
pp. 175-182 ◽  
Author(s):  
Keith B. Tierney ◽  
Eric Stockner ◽  
Christopher J. Kennedy

Abstract This study explored the effects of a sublethal 96-h dehydroabietic acid (DHAA) exposure on aspects of the immune system of juvenile coho salmon under varying temperature conditions. Coho were exposed to DHAA concentrations below the determined LC50 value of 0.94 mg/L (95% confidence limits of 0.81 to 1.24 mg/L) for 96 h at either their acclimation temperature (8 or 18°C), or during an acute warm-shock (8 to 18°C) or cold-shock (18 to 8°C). Acclimation temperature alone significantly affected hematocrit (Hct), neutrophil respiratory burst activity (RBA) and leucocyte proportions. With temperature-shock, leucocrit (Lct), RBA and leucocyte proportions were altered. All parameters were affected by DHAA exposure, but not always in a dose-dependent manner. Across groups, DHAA caused Hct, lysozyme, thrombocyte, neutrophil and monocyte proportions to increase, and Lct, RBA and lymphocyte proportions to decrease. DHAA-temperature interactions resulted in the exacerbation of DHAA-induced effects. Exposure temperature had the most significant effect on the susceptibility of coho to Aeromonas salmonicida; fish were more susceptible at cold temperatures and when subjected to a temperature-shock compared to their respective controls. DHAA exposure modulated the response of temperature-shocked fish to this pathogen.


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