Iodophor Reduces Carnobacterium maltaromaticum and Vagococcus salmoninarum Prevalence During Brook Trout (Salvelinus fontinalis) Spawning.

This study examines the effects of iodophor disinfection on the prevalence of Carnobacterium maltaromaticum and Vagococcus salmoninarum during several years of spawning brook trout (Salvelinus fontinalis). The first year of the study, individual eggs were collected from females and separated into four treatment groups: unfertilised, unfertilised and disinfected, fertilised and fertilised and disinfected. Disinfection consisted of iodophor treatment at 100 ppm for 60 min. All eggs were incubated in TSB and monitored for bacterial growth. No growth was observed from disinfected eggs. However, from non-disinfected eggs, C. maltaromaticum was isolated from the surface of 25% of individual unfertilised and 53% of fertilised eggs. V. salmoninarum was only isolated from non-disinfected fertilised eggs. In year two, the process was repeated, though all eggs were fertilised and iodophor disinfected at 100 ppm for 30 min. Again, the pathogens were present on only a small number of disinfected eggs-V. salmoninarum and C. maltaromaticum were detected from the surface of one and five eggs respectively. Throughout the study we found no evidence of intra-ova transmission from disinfected eggs. The study also demonstrates that iodophor is highly efficacious in reducing the prevalence and transmission risk of these pathogens.