Fish Pathology
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
Research Articles
Prevention of Flavobacterium psychrophilum Vertical Transmission by Iodophor Treatment of Unfertilized Eggs in Salmonids
Akira KumagaiAkatsuki Nawata
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2010 Volume 45 Issue 4 Pages 164-168


We evaluated the efficacy of povidone-iodine treatments in preventing vertical transmission of Flavobacterium psychrophilum in the eggs of masu salmon Oncorhynchus masou, Japanese char Salvelinus pluvius, coho salmon O. kisutch and rainbow trout O. mykiss. When newly spawned eggs were immersion-challenged with F. psychrophilum (> 109 CFU/mL) and subsequently disinfected with povidone-iodine (50 ppm in PBS, 15 min) prior to fertilization, the pathogen was not detected in the contents of the eggs. Without this pre-fertilization disinfection with povidone-iodine, however, procedures such as water-hardening of immersion-challenged eggs in povidone-iodine (50-100 ppm in water) and rinsing of the F. psychrophilum-contaminated eggs with PBS were insufficient to control the intra-ovum infection. In a separate experiment using coho salmon eggs challenged with F. psychrophilum, pre-fertilization disinfection was effective to prevent bacterial cold-water disease in the produced fry. Surface disinfection of unfertilized eggs immediately after spawning is thus essential to prevent vertical transmission of F. psychrophilum.

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© 2010 The Japanese Society of Fish Pathology
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