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Title:

Aquatic Animal Health and Biosecurity Subprogram: Disinfection measures to support biosecurity for infectious spleen and kidney necrosis virus (ISKNV) at aquaculture facilities

Project Number:

2016-011

Organisation:

University of Sydney (USYD)

Principal Investigator:

Joy Becker

Project Status:

Completed

FRDC Expenditure:

$99,992.00

Program(s):

Environment, Industry, People

Need

In the simplest of terms, biosecurity is the protection of living organisms from any type of infectious organism. It can be applied at a local level, such as at a single farm or a national or an international level. One of the best ways to protect fish and safeguard industries and ecosystems, is by preventing and controlling disease with a good biosecurity program. Effective disinfection procedures are important components of disease control and general guidelines for aquatic animal health are available from the OIE. However, interpretation and implementation by industry and regulatory authorities require pathogen specific information. General guidelines for disinfection in response to emergency aquatic animal diseases are provided in AquaVet Plan, Operation Manual for Decontamination (DAWR, 2014-2019) and by the OIE (Aquatic Code, Chapter, 4.3). However, the survival of RSIV outside a host is unknown and disinfection with ether, formalin and chloroform are impractical, particularly without detailed application instructions (OIE Aquatic Manual, Chapter 2.3.7). Biosecurity regulators and farm managers require disinfection efficacy data specific for megalocytiviruses to interpret these guidelines for prevention and control of disease. Detailed disinfection protocols that are efficacious for DGIV in field relevant sample matrices are required. A range of practical methods ensures a suitable procedure can be adapted for the wide range of environments encountered in aquatic health. Given the prior outbreak of DGIV resulting in over 90% of Murray cod dying at a hatchery in Victoria, there is a real risk to domestic aquaculture if DGIV was to become established. There is a critical need to develop and test biosecurity measures to manage the disease risk to Australian fish farms.

Objectives

1. Identify effective disinfection measures to support biosecurity for ISKNV at aquaculture facilities

Disinfection measures to support biosecurity for ISKNV at aquaculture facilities

Report
ISBN:978-1-74210-436-2
ISSN:
Author(s):Joy Becker, Paul Hick and Cahya Fusianto
Date Published:January 2019
Megalocytiviruses are a group of closely related viruses that cause mass mortalities in both marine and freshwater aquaculture. They are of global importance as they are listed by the World Animal Health Organization (OIE). They are difficult to control as they infect over 125 fish species and individuals can be carriers for life with sporadic disease events resulting in considerable losses at farms. This project was developed by the University of Sydney following consultation with Department of Agriculture and Water Resources (DAWR), relevant state agencies dealing with aquatic biosecurity and from advice received from native fish and ornamental fish aquaculture producers. Research has shown that imported ornamental fish are a pathway for Megalocytivirus to enter Australia. There was a critical need to develop practical and efficacious disinfection protocols for recirculating aquaculture systems. We used ISKNV freshly amplified in vivo at low passage to evaluate eight disinfection procedures using a bioassay with Murray cod (Maccullochella peelii) as a sensitive test for infectious virus. The six disinfection protocols that produced negative bioassays and were considered effective are described in this report. Further, it was demonstrated that ISKNV remained infectious in aquarium water (void of fish) at 25°C for at least 48 hours. Recommendations have been made to revise operational and disease strategy manuals as part of AQUAVETPLAN and an awareness program for increased reporting of mortality events at ornamental fish aquatic facilities for emergency disease response. The research findings will be used by biosecurity regulators and farm managers for disinfection efficacy data specific for ISKNV. These virus specific data enable interpretation of disinfection guidelines for the prevention and control of disease caused by ISKNV. The project was funded by the Australian Government Department of Agriculture and Water Resources through the Fisheries Research and Development Corporation.