3 results

NCCP: Fishing Australia National Carp Control Program Episodes

Project number: 2016-163
Project Status:
Completed
Budget expenditure: $44,000.00
Principal Investigator: Rob Paxevanos
Organisation: The Fishing Guy
Project start/end date: 20 Jun 2017 - 13 May 2019
Contact:
FRDC
TAGS
Media
Invasive Species
Community
SPECIES
European Carp
Tench
Goldfish

Need

Commercial in confidence. To know more about this project please contact FRDC.

Objectives

Commercial in confidence

Final report

Author: Rob Paxevanos
Final Report • 2019-03-17 • 405.60 KB
2016-163-DLD.pdf

Summary

The present communications activity, undertaken by The Fishing Guy (Rob Paxevanos), was developed to ensure the NCCP’s story is presented with integrity and is illuminated in the TV broadcast and multi media arena via the commissioning of the production detailed in this report.

 

Aquatic Animal Health Subprogram: Optimisation of PCR tests for diagnosis of megalocytivirus (gourami iridovirus) and cyprinid herpesvirus 2 (goldfish herpesvirus)

Project number: 2007-007
Project Status:
Completed
Budget expenditure: $104,000.00
Principal Investigator: Richard Whittington
Organisation: University of Sydney (USYD)
Project start/end date: 16 Jun 2007 - 30 Sep 2008
Contact:
FRDC
TAGS
Stock Assessment
Policy
Harvest Strategy
Fisheries Management
Data
SPECIES
Silver Perch
Golden Perch
Australian Bass
Goldfish
Murray Cods

Need

Megalocytivirus
In 2003 there was an outbreak of iridovirus in farmed Murray cod in Victoria that caused 90% losses. In 2004 these viruses were found in imported ornamental fish - gourami. These have established breeding populations in the wild in Australia and therefore may pose a threat to biodiversity in the Murray-Darling Basin and other systems in which Maccullochella sp. still exist. These viruses are not host specific and all Murray-Darling Basin sp. may be susceptible. Due to the risk to aquaculture, recreational fisheries and biodiversity, there is need to develop and validate diagnostic tests for GIV in order to enable rapid accurate detection of GIV, facilitate surveys of Murray cod and imported ornamental fish to improve risk assessment and conduct surveys of free-living and farmed fish in Australia. The specific tests required include a robust and accurate PCR, and cell culture. These tests need to be able to distinguish GIV from related iridoviruses such as RSIV.

CyHV-2 of goldfish
In the last 10 years imported goldfish numbers have continued to grow, in part, due to their competitive price. The imported goldfish have been subjected to the AQIS requirements for import certification and a 3 week holding period before release. Anecdotal evidence suggests that mortality rates of domestically produced goldfish increase when these fish are mixed in retail shops with imported goldfish. Investigations have revealed pathology consistent with CyHV-2. Imported goldfish may carry latent CyHV-2 infections. This project aims to provide the diagnostic capability and a sampling regime to further investigate these concerns.

The project relates directly to Strategies 1, 2 and 3 in Aquaplan 2005-2010 and meets key research area 7.2.1 in the FRDC Aquatic Animal Health Sub Program Research and Development Plan 2002-2008 (updated June 2005).

Objectives

1. To optimise a PCR for detection of megalocytivirus
2. To optimise a PCR for detection of CyHV-2 in goldfish
3. To transfer technology to diagnostic laboratories in Australia

Final report

ISBN: 978-1-74210-138-5
Author: Richard Whittington
Final Report • 2009-07-17
2007-007-DLD.pdf

Aquafin CRC - Atlantic Salmon Aquaculture Subprogram: development of selective enrichment culture-polymerase chain reaction (SEC-PCR) for the detection of bacterial pathogens in covertly infected farmed salmonid fish

Project number: 1999-201
Project Status:
Completed
Budget expenditure: $155,784.00
Principal Investigator: Jeremy Carson
Organisation: University of Tasmania (UTAS)
Project start/end date: 19 Sep 1999 - 30 Jun 2003
Contact:
FRDC
TAGS
Disease
Aquaculture
SPECIES
Greenback Flounder
Striped Trumpeter
Silver Perch
Goldfish
Atlantic Salmon

Need

The ability to detect infected animals is an essential requirement in animal health monitoring and surveillance. A major problem of testing farmed and wild fish is the absence of simple diagnostic tests for the detection of asymptomatic carrier fish. Where tests are available, they are resource intensive and time consuming such as the heat+corticosteroid stress test for furunculosis in salmonids. This test is used for disease control measures in eastern Canada and has been instrumental in limiting spread of furunculosis to sea cage farms (Olivier 1992). Active surveillance of animal populations is considered an important approach in animal health monitoring (Stark 1996) and is of particular relevance with publication by the Office International des Epizooties of its guidelines in the International Aquatic Animal Health Code (Anon 1997) for defining disease-free status.

Demonstration of freedom from disease, both covert and overt, within a region or a country, can be an asset when selling live and uncooked product in markets overseas. As global trade develops, Australia will need to demonstrate freedom from disease not just as a marketing strategy but as an essential requirement of trade and as a means of protecting or limiting the spread of disease.

This project aims to develop a hybrid technology derived from the food industry. It will require adaptation and refinement for use with fish pathogens and development of test protocols for screening adequate numbers of fish. The use of specialised enrichment culture media with the sensitive and specific techniques of PCR should provide a useful and sensitive tool in active surveillance of fish populations and fish products. This technology will also have application in screening ornamental fish entering Australia as well as uncooked fish products.

Detection of bacterial pathogens using immunological markers or DNA are termed proxy tests since the presence of the pathogen is inferred. Proxy tests pose two major problems: firstly what is the relationship of the proxy measure to the intact target pathogen and secondly, what is the biological significance of the proxy test? Validation of proxy tests is a recognised problem that if unresolved can seriously restrict the use of such tests (Hiney 1997). The proposed project solves many of these issues of validation: the primary test requires amplification of the target pathogen by culture and hence is not a proxy test. Detection of the target pathogen after culture utilises a secondary proxy test but it can be internally validated by secondary culture as required. The test system will be evaluated against farmed populations of fish to determine the significance of findings, a pre-requisite for external validation. Correlations of this type have not been undertaken previously and the strategies proposed in this project represent a realistic attempt to convert bench tests into practical and robust diagnostic tools.

References:

Anon (1997) International Aquatic Animal Health Code. 2nd edit. Office International des Epizooties, Paris.
Hiney M. (1997) How to test a test: methods of field validation for non-culture based detection techniques. Bull. Eur. Ass. Fish Path. 17:245-250
Olivier G (1992) Furunculosis in the Atlantic provinces: an overview. Bull. Aquacul. Assoc. Canada 92-1: 4-10.
Stark K D C (1996) Animal health monitoring and surveillance in Switzerland. Aus. Vet. J. 73:96-97.

Objectives

1. Develop a procedure for extracting bacterial DNA from the selective enrichment media that is suitable for the PCR process and is suitable for processing multiple samples.
2. Determine optimum conditions for the PCR test to maximise specificity and sensitivity of the procedure.
3. Develop a test procedure based on immuno-ELISA capture that will verify any positive PCR reactions using a secondary confirmatory gene probe and is suitable for testing multiple samples.
4. Optimise the PCR conditions to incorporate a PCR protection system to protect tests against false positive reactions arising from contamination.
5. Optimise the culture conditions and PCR detection process to ensure the minimum test time between sample collection and test result.
6. Test populations of salmonids with the optimised SEC-PCR system to verify test performance and obtain baseline data on carrier prevalence.

Final report

Author: Jeremy Carson and Teresa Wilson
Final Report • 2003-05-30 • 6.17 MB
1999-201-DLD.pdf

Summary

Bacterial disease is a major cause of stock loss in aquaculture. The severity of infection may range from acute to chronic through to benign. This latter condition, termed covert infection, is insidious, as fish may appear to be outwardly healthy but during periods of stress, these carriers may breakdown leading to spread of infection and development of a disease outbreak.

Several bacterial pathogens, known to exist in Australia and the cause of significant disease episodes in Atlantic salmon and rainbow trout, can cause covert infections including: atypical Aeromonas salmonicida, Lactococcus garvieae, Tenacibaculum maritimum and Yersinia ruckeri.

Early detection of covertly infected fish is considered desirable as it provides a means of determining a suitable disease control strategy such as imposing movement restrictions to prevent the spread of disease, changing management practices to avoid stress or determining the spread of disease in a population at risk of infection. The standard method for identifying carriers is to stress a cohort of fish using a combination of heat andi mmunosuppression to force covertly infected fish to breakdown with disease. This form of testing is undesirable for animal welfare considerations, is difficult to accomplish and takes over three weeks to generate results.

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