The Effect of Disinfection Strategies on Transmission of Aeromonas
salmonicida and Yersinia ruckeri in a Recirculating Aquaculture System
G.L. Bullocka*, W.B. Schillb
Volume 7, June 2006
a*
The Conservation Fund Freshwater Institute
1098 Turner
Road
Shepherdstown, WV 25443 USA
e-mail:
b
U.S.
Geological Service
National Fish Health Research Laboratory
11649 Leetown
Road
Kearneysville, WV 25430 USA
*Corresponding Author
Keywords: furunculosis, enteric redmouth disease, recirculating,
biofilters, disinfection
Footnote
International Journal of Recirculating Aquaculture 7 (2006). All Rights
Reserved
© Copyright 2006 by Virginia Tech and Virginia Sea Grant, Blacksburg, VA
USA
ABSTRACT
Continuous addition of Aeromonas salmonicida (which causes furunculosis) or
Yersinia ruckeri (which causes enteric redmouth disease, or ERM) broth cultures
to recirculating aquaculture systems, without fish, resulted in the presence
of these pathogens in the fluidized sand biofilters. Disinfection of the recirculating
systems, except biofilters, with 200 ppm sodium hypochlorite and flushing biofilters
for 24 hours with filter-sterilized spring water (FSSW)did not prevent outbreaks
of furunculosis or enteric redmouth disease after stocking Arctic char (Salvelinus
alpinus) or rainbow trout (Oncorhynchus mykiss), respectively. Disinfection
of the entire recirculating systems with 10 ppm Chloramine-T following outbreaks
of furunculosis or ERM, or after addition of broth cultures prevented transmission
of ERM in three trials and in two of three trials with furunculosis. Within
75 days of stocking Atlantic salmon (Salmo salar) with subclinical furunculosis
in the recirculating system with rainbow trout, A. salmonicida could be cultured
from the mucus of rainbow trout and from the fluidized sand biofilters. Removal
of salmon and trout and disinfection of the recirculating system with 10 ppm
Chloramine-T prevented a furunculosis outbreak when Arctic char were stocked
into the system. However, if the recirculating system was only drained and
refilled after removal of salmon and trout, furunculosis occurred within seven
days of stocking char.
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