[Prophylactic and control of infectious hematopoietic necrosis virus (IHN) at salmon hatcheries]
2009
Rudakova, S.L., Kamchatka Research and Development Inst. of Fisheries and Oceanography, Petropavlovsk-Kamchatsky (Russian Federation)
A retrospective analysis of efficiency of anti-epizootic actions for infectious necrosis of hemopoietic tissue (IHN) at salmon hatcheries (SH) in RF and USA is presented. Methods of selection, incubation of fish eggs, growing larvae and salmon young fish at fisheries in Kamchatka are considered. As is shown, practicing methods of prophylactics and control of IHN did mot meet the world standards and did not prevent from epizootic outbreaks. The virus titer was high in all the biomaterial samples tested promoting both horizontal transmission from infected individuals to non-infected fishes and vertical – from parents to offspring. The actions of preventing and controlling IHN comprise: disinfection of implements, spawners, and fish eggs during fertilization and incubation with an iodine solution. The increasing the disinfection time of small volumes of fish eggs from 10 min to 60 min did not influence their quality and losses, but promoted destruction of virus on the surface of fish eggs and in perivitelline space. The efficiency of disinfection was improved by iodine retreatment for 20 min. it is recommended to divide fertilized fish eggs and juveniles produced from there into maximum number of groups followed by incubation. Analysis of comparative data of the losses under incubation and growing larvae of red salmon has shown that the new methods of prophylaxis and control prevented epizooties of IHN. In view of high virus carriage among mature red salmons and different IHNV virulence with insufficiently effective actions of prophylaxis in Kamchatka it is required to revise the acting instructions to prevent and control infectious necrosis of hemopoietic tissue of salmons to avoid IHN epizooties
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