The National Carp Control Plan (NCCP), an initiative of the Australian government, aims to reduce common carp numbers in Australian waters. A key aspect of this plan is to use a biological control agent to kill common carp in waters of the Murray-Darling basin. Since 2008 CSIRO researchers have been investigating the potential for Cyprinid herpesvirus 3 (CyHV-3) to control common carp numbers in this region as well as exploring potential negative outcomes arising from the introduction of this exotic virus. One critical issue is the potential for non-target species (NTS) to be infected and negatively affected by CyHV-3.
Susceptibility studies performed in vitro and in vivo were undertaken and used to predict in situ outcomes. These studies indicated that NTS tested were not susceptible to CyHV-3. However, since the publication of these results, stakeholder groups have raised several concerns. These concerns must be resolved to mitigate against the infection of NTS by CyHV-3 and to ensure continued stakeholder engagement. Six areas of concern have been raised by stakeholders.
1. Immune-competency status of fish was not considered in susceptibility studies
2. Techniques used to determine viral infection were perceived to be unreliable
3. Undiagnosed mortalities of NTS were not adequately addressed
4. Positive PCR test results observed in NTS were not adequately explained
5. Only mature or advanced juvenile fish were assessed for susceptibility to CyHV-3
6. The range of NTS investigated for susceptibility was limited and did not include a number of species that may be exposed to CyHV-3
It is proposed that a discussion paper be prepared to examine these issues. This paper would determine if previous susceptibility testing for CyHV-3 in the NCCP adequately addressed those issues detailed above. Using the information collected, recommendations for susceptibility testing of NTS to CyHV-3 in the context of the NCCP would be presented. The current understanding of what constitutes best practice for viral susceptibility testing at the time of the review would also be discussed. This would include a commentary on the predictive capacity of in vitro and in vivo studies when translated to the in situ environment.
Project number:
2017-127
Project Status:
Completed
Budget expenditure:
$124,626.00
Principal Investigator:
Stephen B. Pyecroft
Organisation:
University of Adelaide Roseworthy Campus
Project start/end date:
3 Dec 2017
-
29 Nov 2018
Contact:
FRDC
TAGS
SPECIES
1. The overarching objective of this project is to investigate potential problems, limitations and concerns related to viral susceptibility testing of NTS to CyHV-3 in the context of the NCCP and to define what constitutes best practice in viral susceptibility testing.
2. Review and discuss the implications of immune-competency status in pathogen susceptibility testing of aquatic organisms.
3. Review the range of techniques for assessing viral infection in aquatic animals and evaluate their accuracy and reliability.
4. Discuss the occurrence and implications of undiagnosed mortalities and ‘false positives’ in pathogen susceptibility studies.
5. Determine, based on existing literature, potential differences in the susceptibility of larval, juvenile and mature fish to viruses.
6. Investigate, based on existing literature, the potential for fish and other aquatic organisms beyond those previously investigated by the NCCP to become infected by CyHV-3 as a result of actions of the NCCP.
Author:
Stephen B. Pyecroft and Ben Jones
PROJECT NUMBER
•
2019-176
PROJECT STATUS:
COMPLETED
NCCP: Determination of the susceptibility of silver perch, Murray cod and rainbow trout to infection with CyHV-3
1. To determine the susceptibility of silver perch to infection with CyHV-3
ORGANISATION:
CSIRO Australian Animal Health Laboratory
PROJECT NUMBER
•
2019-163
PROJECT STATUS:
COMPLETED
NCCP: Understanding the genetics and genomics of carp strains and susceptibility to CyHV-3
1. Determine the likely genes responsible for resistance of carp to CyHV-3.
ORGANISATION:
CSIRO Australian Animal Health Laboratory
PROJECT NUMBER
•
2018-189
PROJECT STATUS:
COMPLETED
NCCP: Socio-economic impact assessment and stakeholder engagement
1. Communication and engagement with stakeholders contributes to integration of stakeholder perspectives into development of the Plan
ORGANISATION:
University of Canberra