Detailed Research Information

Detailed project information for
Study Plan Number 01072-03

Branch : Fish Health Branch

Study Plan Number : 01072-03

Study Title : Enhanced survival of Atlantic salmon after vaccination against furunculosis

Starting Date : 08/01/1996

Completion Date : 09/30/1999

Principal Investigator(s) : Cipriano, Rocco C.

Primary PI : Cipriano, Rocco C.

Telephone Number : (304) 724-4432

Email Address : rocco_cipriano@usgs.gov

SIS Number : 5002163

Primary Program Element : Fisheries and Aquatic Resources

Second Program Element : Application of Science Information to Management

Status : Completed

Abstract : United States federal restoration efforts in New England focus principally on Atlantic salmon (Salmo salar) in the Connecticut, Merrimack, Penobscot and several of the Downeast rivers in Maine. Although remnant populations of naturally reproducing Atlantic salmon exist in Maine, other stocks depend almost entirely upon fish of hatchery origin. Mature sea-run returns to all rivers are numerically small (maximum of several hundred fish) and comprise a genetically important source of gametes. Consequently, no legal fishery exists for Atlantic salmon within the geographic area encompassed by the New England restoration effort. Fish health policies were adopted to reduce contagion and minimize the deleterious effects of infectious diseases inherent at various stages in the culture of Atlantic salmon used within the restoration program. Contagion and mortality are amplified by maintaining non-feeding, sea-run Atlantic salmon in holding facilities upon return from ocean migrations. Infection is further exacerbated by holding domestic brood stocks and their progeny under intensive culture. Sea-run and hatchery stocks of Atlantic salmon are exposed to numerous stressors and conditions which predispose these fish to pathogens that adversely affect survival. Aeromonas salmonicida, etiologic agent of furunculosis, is a concern throughout the region encompassed by the New England restoration effort. Sea-run return Atlantic salmon sustain significant mortalities (over 60%) to furunculosis from the time of their return in May until they are spawned in the following October/November. This necessitated a strategy to reduce mortality and maximize the number of eggs produced to continue the restoration effort. Therefore, these fish were injected intraperitoneally with 2.4 mg of oxolinic acid plus 0.5 mL of a commercial furunculosis bacterin/kg of body weight. Use of the immunotherapeutic protocol combined with the advance of non-lethal procedures for monitoring infection status have decreased holding mortality to furunculosis to less than 1%. As an adjunct to this study, a USFWS grant was received to evaluate the use of commercially produced transport tubes to assist in the nonlethal diagnosis of Aeromonas salmonicida among vaccinated and non-vaccinated salmon. In vitro studies indicated that commercially prepared transport systems containing Amies, Stuart’s, and Cary-Blair media worked equally well in sustaining the viability of the fish pathogen Aeromonas salmonicida, cause of furunculosis. The bacterium remained viable without significant increase or decrease in cell numbers for up to 48 hours of incubation at 18-20oC in Stuart’s Transport Medium and, consequently, obtaining mucus samples in such tubes were compared to on-site detection of A.salmonicida by dilution plate counts on Coomassie Brilliant Blue Agar. In three different assays of 100 samples of mucus from Atlantic salmon (Salmo salar) infected subclinically with A. salmonicida, dilution counts conducted on-site proved more reliable to detect the pathogen than obtaining the samples in the transport system. In such assays, dilution counts detected the pathogen in 34, 41, and 22 samples whereas this was accomplished in only 15, 15, and 3 of the respective samples when the transport system was used. In an additional experiment, Arctic char (Salvelinus alpinus) sustaining a frank epizootic of furunculosis were sampled similarly. Here, too, dilution counts were more predictive of the prevalence of A. salmonicida and detected the pathogen in 46 mucus samples. By comparison, only 6 samples collected by using the transport system were positive. It was also observed that the transport system supported the growth of the normal mucus bacterial flora. Particularly predominant among these were motile aeromonads and Pseudomas fluorescens. In mixed culture growth studies, two representatives of both of the latter genera of bacteria outgrew A. salmonicida and, in some cases, to the total exclusion of the pathogen, itself.

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Branch :	Fish Health Branch
Study Plan Number :	01072-03
Study Title :	Enhanced survival of Atlantic salmon after vaccination against furunculosis
Starting Date :	08/01/1996
Completion Date :	09/30/1999
Principal Investigator(s) :	Cipriano, Rocco C.
Primary PI :	Cipriano, Rocco C.
Telephone Number :	(304) 724-4432
Email Address :	rocco_cipriano@usgs.gov
SIS Number :	5002163
Primary Program Element :	Fisheries and Aquatic Resources
Second Program Element :	Application of Science Information to Management
Status :	Completed
Abstract :	United States federal restoration efforts in New England focus principally on Atlantic salmon (Salmo salar) in the Connecticut, Merrimack, Penobscot and several of the Downeast rivers in Maine. Although remnant populations of naturally reproducing Atlantic salmon exist in Maine, other stocks depend almost entirely upon fish of hatchery origin. Mature sea-run returns to all rivers are numerically small (maximum of several hundred fish) and comprise a genetically important source of gametes. Consequently, no legal fishery exists for Atlantic salmon within the geographic area encompassed by the New England restoration effort. Fish health policies were adopted to reduce contagion and minimize the deleterious effects of infectious diseases inherent at various stages in the culture of Atlantic salmon used within the restoration program. Contagion and mortality are amplified by maintaining non-feeding, sea-run Atlantic salmon in holding facilities upon return from ocean migrations. Infection is further exacerbated by holding domestic brood stocks and their progeny under intensive culture. Sea-run and hatchery stocks of Atlantic salmon are exposed to numerous stressors and conditions which predispose these fish to pathogens that adversely affect survival. Aeromonas salmonicida, etiologic agent of furunculosis, is a concern throughout the region encompassed by the New England restoration effort. Sea-run return Atlantic salmon sustain significant mortalities (over 60%) to furunculosis from the time of their return in May until they are spawned in the following October/November. This necessitated a strategy to reduce mortality and maximize the number of eggs produced to continue the restoration effort. Therefore, these fish were injected intraperitoneally with 2.4 mg of oxolinic acid plus 0.5 mL of a commercial furunculosis bacterin/kg of body weight. Use of the immunotherapeutic protocol combined with the advance of non-lethal procedures for monitoring infection status have decreased holding mortality to furunculosis to less than 1%. As an adjunct to this study, a USFWS grant was received to evaluate the use of commercially produced transport tubes to assist in the nonlethal diagnosis of Aeromonas salmonicida among vaccinated and non-vaccinated salmon. In vitro studies indicated that commercially prepared transport systems containing Amies, Stuart’s, and Cary-Blair media worked equally well in sustaining the viability of the fish pathogen Aeromonas salmonicida, cause of furunculosis. The bacterium remained viable without significant increase or decrease in cell numbers for up to 48 hours of incubation at 18-20oC in Stuart’s Transport Medium and, consequently, obtaining mucus samples in such tubes were compared to on-site detection of A.salmonicida by dilution plate counts on Coomassie Brilliant Blue Agar. In three different assays of 100 samples of mucus from Atlantic salmon (Salmo salar) infected subclinically with A. salmonicida, dilution counts conducted on-site proved more reliable to detect the pathogen than obtaining the samples in the transport system. In such assays, dilution counts detected the pathogen in 34, 41, and 22 samples whereas this was accomplished in only 15, 15, and 3 of the respective samples when the transport system was used. In an additional experiment, Arctic char (Salvelinus alpinus) sustaining a frank epizootic of furunculosis were sampled similarly. Here, too, dilution counts were more predictive of the prevalence of A. salmonicida and detected the pathogen in 46 mucus samples. By comparison, only 6 samples collected by using the transport system were positive. It was also observed that the transport system supported the growth of the normal mucus bacterial flora. Particularly predominant among these were motile aeromonads and Pseudomas fluorescens. In mixed culture growth studies, two representatives of both of the latter genera of bacteria outgrew A. salmonicida and, in some cases, to the total exclusion of the pathogen, itself.
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U.S. Department of the Interior \|\| U.S. Geological Survey 11700 Leetown Road, Kearneysville, WV 25430, USA URL: http://www.lsc.usgs.gov Maintainer: lsc_webmaster@usgs.gov Last Modified: October 21, 2002 dwn Privacy Policy and Disclaimers \|\| FOIA \|\| Accessibility