Understanding White Spot Syndrome Virus (WSSV) Transmission In Moreton Bay - Epidemiological Modelling Of Surveillance Data
Funder
Fisheries Research and Development Corporation
Funding Amount
$135,000.00
Summary
On the basis of Biosecurity Queensland (BQ) surveillance April 2020 which detected 112 mangrove crabs positive to white spot syndrome virus (WSSV), and their confirmation just a few weeks later that two farms on the Logan River had samples testing positive for WSSV, APFA Management Committee identified a need for a qualified epidemiologist to undertake comprehensive modelling to: 1) Identify what vectors/sentinels are involved in the spread of WSSV and design surveillance for these 2) In ....On the basis of Biosecurity Queensland (BQ) surveillance April 2020 which detected 112 mangrove crabs positive to white spot syndrome virus (WSSV), and their confirmation just a few weeks later that two farms on the Logan River had samples testing positive for WSSV, APFA Management Committee identified a need for a qualified epidemiologist to undertake comprehensive modelling to: 1) Identify what vectors/sentinels are involved in the spread of WSSV and design surveillance for these 2) Investigate at what rate WSSV is spreading by defining the current zone 3) Understand how seasonal factors could impact the spread 4) Advise whether the boundary of the current zone is likely to be changed.
There is significant surveillance data available from several studies and several years of surveillance. This data has not undergone extensive, systematic and comprehensive analysis to determine risk factors, spread etc. There is information suggesting that sentinel vectors carrying WSSV can change year to year and it is important to predict what vectors will be involved in spreading WSSV in the future to ensure appropriate biosecurity measures and monitoring can take place. Clear independent epidemiological advice around the potential sources and likely spread is needed. Working out which animals form proper sentinels is important and will not only describe how WSSV moves around in the environment, what the zones look like, but also how to target mitigation measures.
This information will assist the prawn farming industry initiate appropriate management practices on an enterprise and regional level and to improve their biosecurity plans and potentially inform industry and policy makers on the benefits of a regional or zone-based management plan. Understanding whether WSSV remained within the environment at low prevalence for 2017-2020, or whether there was a separate incursion in 2020 is beneficial because the management protocol will be different in each scenario. In addition, understanding of risk factors will assist predictions about where and if this virus is most likely to spread? Objectives: 1. Identify vectors/sentinels involved in the spread of WSSV, designing surveillance for these. 2. Investigate the rate at which WSSV is spreading by defining the current zone. 3. Understand how seasonal factors (e.g. rainfalls, temperature changes) impact the spread of WSSV. 4. Advise whether the boundary of the current zone is likely to change geographically and if so, establish the likely rate of movement in time based on current indicators. 5. Examine other risk factors for disease transmission and spread Read moreRead less
The WSD outbreak and subsequent significant mortality events is a massive threat to the prawn aquaculture industry throughout Australia. WSD is an exotic disease, resulting in the emergency animal disease provisions being implemented by State and Commonwealth governments. The response so far is to attempt to eradicate the disease by destruction of diseased stock and implementation of quarantine arrangements. This has resulted in the loss of millions of dollars to the prawn farming industry. In ....The WSD outbreak and subsequent significant mortality events is a massive threat to the prawn aquaculture industry throughout Australia. WSD is an exotic disease, resulting in the emergency animal disease provisions being implemented by State and Commonwealth governments. The response so far is to attempt to eradicate the disease by destruction of diseased stock and implementation of quarantine arrangements. This has resulted in the loss of millions of dollars to the prawn farming industry. In addition to the prawn farmers, other industries affected include wild prawns, crabs and recreational fishers.
A coordinated response from the Australian prawn farming industry is needed to ensure Federal and State stakeholders will have the confidence to provide targeted assistance and to ensure that that efforts by all stakeholders are not duplicated and / or contradictory.
Objectives: 1. Deliver a Prawn Industry WSD Response Plan covering actions that can be implemented on individual farms by the whole of industry and government. 2. To prepare a plan for the prawn farming industry and its stakeholders to respond to WSD in the short, medium and long term. 3. Provide assistance to APFA in consultation with stakeholders, identification of sources of assistance and coordination of the stakeholder response to WSD. Read moreRead less
Assessment Of The Sensitivity Of Australia’s Aquatic Animal Disease Surveillance System Using Scenario Tree Modelling
Funder
Fisheries Research and Development Corporation
Funding Amount
$224,000.00
Summary
The sensitivity of an overall passive surveillance system is difficult to determine due to variability in factors such as disease characteristics, passive surveillance stakeholders and the likelihood that disease events will be reported and investigated. The WOAH Aquatic Animal Health Code also stipulates the primary evidence for historical freedom is passive surveillant information generated by a country’s early detection system that needs to be sufficiently sensitive.
Scenario tree m ....The sensitivity of an overall passive surveillance system is difficult to determine due to variability in factors such as disease characteristics, passive surveillance stakeholders and the likelihood that disease events will be reported and investigated. The WOAH Aquatic Animal Health Code also stipulates the primary evidence for historical freedom is passive surveillant information generated by a country’s early detection system that needs to be sufficiently sensitive.
Scenario tree modelling (STM) can be used to overcome those challenges. STM uses quantitative statistical methods to estimate the sensitivity of various components of the surveillance system (e.g. presentation of disease signs, disease recognition and reporting). These estimates can then be used to identify critical points in the system to which interventions can be targeted to improve the system. STM can be applied to any aquatic disease/industry of interest and there are some successful examples for terrestrial diseases/industries, both in Australia and overseas.
Two aquatic animal disease agents of trade and biosecurity significance, WSSV and megalocytiviruses, will be evaluated as case studies. These diseases are subject to import biosecurity measures and have significant production impacts, as they severely affect farmed and wild aquatic animal species that are valued by many stakeholders (e.g. aquaculture, capture fisheries, recreational fisheries and conservation groups). A sound STM assessment of each case study will support our early detection system through a quantitative evaluation of the speed of the detection, and improve our emergency disease response strategy by determining areas in our passive surveillance that, once strengthened, will provide a greater return on future investment.
As mentioned above, increasing the sensitivity of Australia’s passive surveillance is a national priority. This project is identified in AQUAPLAN 2022-2017 as Activity 3.3. The outcomes of this project are also used for other AQUAPLAN activities, National surveillance strategy (Activity 3.1) and Sector-specific surveillance plans (Activity 3.2). The data produced from this project will provide recommendations for various interventions to improve the overall performance of the passive surveillance system for the participating industries.
More broadly, the Fisheries Research and Development Corporation R&D Plan 2020-2025 identified building capability and capacity for biosecurity as a priority. In alignment with the R&D plan, successful outcomes of this project will improve understanding of disease transmission pathways which will enhance biosecurity practices. It will improve allocation of biosecurity resources (by identifying the most effective and cost-efficient way of investing resources in surveillance to get the best return), minimise biosecurity threats (by enhancing passive surveillance to accelerate an early detection) and improve market access for associated industry producers (by providing quantitative information on their passive surveillance sensitivity as a market access negotiation tool).
Objectives: 1. Quantitatively evaluate the sensitivity of Australia’s passive surveillance system for white spot disease 2. Quantitatively evaluate the sensitivity of Australia’s passive surveillance system for megalocytiviruses Read moreRead less
White Spot Syndrome Virus (WSSV) Preparedness For Biosecurity Awareness And Adoption Of Best Practice By The NSW And QLD Wild Catch Commercial Fishers - Understanding What Extension Pathways Work Best
Funder
Fisheries Research and Development Corporation
Funding Amount
$84,000.00
Summary
Objectives: 1. Develop appropriate extension material to reduce the risk of spread of WSSV from the control zone to the non control zones in QLD and NSW. 2. To quantify best extension practice for biosecurity for the commercial wild catch fishers. 3. To, where possible, utilise existing extension material developed by Biosecurity Queensland for the commercial wild catch fishery.
Field Observations And Assessment Of The Response To An Outbreak Of White Spot Disease (WSD) In Black Tiger Prawns (Penaeus Monodon) Farmed On The Logan River In November 2016
Funder
Fisheries Research and Development Corporation
Funding Amount
$52,663.15
Summary
Objectives: 1. Undertake assessment on the causative factors for the outbreak of WSD in the prawn farms in the Logan River region 2. Provide technical advice to APFA, QSIA, ACPF, Sunfish, ARFF and FRDC on the technical information arising from the eradication program for WSD 3. Undertake research and sampling for later assessment on how to improve the management of WSD and its erradication
Clarence River Green Prawn Market Diversification Assistance Measures
Funder
Fisheries Research and Development Corporation
Funding Amount
$165,000.00
Summary
The Clarence River Region is known for its high-quality prawn markets. The region was kept profitable during COVID restrictions due to a significant portion of the fisher directing its product to the highly profitable bait market. This diversification away from the consumer market has ensured stability for the region. Many fishing businesses pivoted their strategies to meet this new buyer to the region. The loss of the uncooked prawn market in the Clarence region will therefore destabilize t ....The Clarence River Region is known for its high-quality prawn markets. The region was kept profitable during COVID restrictions due to a significant portion of the fisher directing its product to the highly profitable bait market. This diversification away from the consumer market has ensured stability for the region. Many fishing businesses pivoted their strategies to meet this new buyer to the region. The loss of the uncooked prawn market in the Clarence region will therefore destabilize the industry. The restriction of uncooked prawn trade therefore must be addressed through market research, diversification and activation. However, there is immediate need for alternative markets so an intense focused market activation and access is the key. PFA has identified key market persons that can create links between industry and high-end chefs to: 1. Identify alternative market uses that fall within the quarantine requirements 2. Start immediate market trials and activation 3. Review online presence and build industry skills to improve online presence for sales • It is intended that this will lead into immediate supply agreements to these alternative markets that will in turn remove burden on the existing cooked prawn market
Objectives: 1. To identify and trial supplies of Clarence River prawns to alternative market 2. To activate alternative markets to reduce negative impact of trade restriction to the Clarence River region 3. To build skills within local fishers to build online presence Read moreRead less
Collation Of White Spot Syndrome Virus Testing From Wild-caught Re-imported Prawns
Funder
Fisheries Research and Development Corporation
Funding Amount
$2,300.00
Summary
Wild caught prawns that are re-imported into Australia are required to be tested for white spot syndrome virus, the virus that causes WSD. Examination of these data could reveal if any positive test results have been recorded to date. Objectives: 1. Summarise available white spot syndrome virus testing data from wild-caught re-imported prawns
Assessment Of Gamma Irradiation As A Feasible Method For Treating Prawns To Inactivate White Spot Syndrome Virus
Funder
Fisheries Research and Development Corporation
Funding Amount
$220,000.00
Summary
Achieving the mandated dose rate of 50 kGy for prawns harvested from the White Spot Disease control zone in SE QLD is proving to be problematic and industry are requesting a reduction in the permitted irradiation dose rate for prawns sourced from Moreton Bay to somewhere between 15 and 25 kGy. A reduction in treatment dose, if successful, would provide a viable option for industry to continue trade in uncooked prawns sourced from Moreton Bay.
There appears to be only three scientific p ....Achieving the mandated dose rate of 50 kGy for prawns harvested from the White Spot Disease control zone in SE QLD is proving to be problematic and industry are requesting a reduction in the permitted irradiation dose rate for prawns sourced from Moreton Bay to somewhere between 15 and 25 kGy. A reduction in treatment dose, if successful, would provide a viable option for industry to continue trade in uncooked prawns sourced from Moreton Bay.
There appears to be only three scientific papers relevant to the subject of using gamma irradiation for inactivation of WSSV (Heidareh et al. 2014, Kakoolaki et al. 2015, Motamedi-Sedeh et al. 2017). The studies were conducted with the aim of determining the doses required to inactivate the Iranian isolate of WSSV with gamma irradiation for the purposes of vaccinating cultured prawns. While the listed scientific papers suggest gamma irradiation at a dose of around 13-15 kGy is effective at inactivating WSSV, their experimental protocols and results are not clearly transferable. In these studies aliquots of free virus were exposed to different gamma irradiation doses. Irradiation of WSSV inside infected host tissues was not performed, and data on whether the surviving prawns were infected with WSSV were not presented. None of these papers are therefore directly applicable to the situation relating to irradiation treatment of WSSV in-situ inside infected prawns.
Given the absence of information on irradiation doses for inactivation of WSSV in the Department of Agriculture (2014) review document, and the absence of research in Australia or overseas to validate alternative irradiation doses that completely inactivate WSSV, new research is urgently required to determine the minimum safe irradiation dose for inactivation of WSSV in prawns with the results verified by controlled challenge trials in a bio-secure facility.
Objectives: 1. To determine minimal effective dose of gamma irradiation to render WSSV non-infectious in prawns. Read moreRead less