Improving early detection surveillance and emergency disease response to Pacific Oyster Mortality Syndrome (POMS) using a hydrodynamic model for dispersion of OsHV-1
Department of Primary Industries and Regions South Australia (PIRSA)
Pacific Oyster Mortality Syndrome (POMS) is a disease caused by Ostreid Herpesvirus type 1 (OsHV-1) microvariant, which causes rapid high mortalities (up to 100%) in Pacific oysters. POMS has caused significant economic impacts to the oyster growing industry in parts of NSW and Tasmania where it occurs. On 28 February 2018 OsHV-1 was first detected in Port Adelaide River feral oyster populations. PIRSA and industry mounted an immediate emergency response aimed at containing the virus to the Port and preventing spread to the nearby oyster industry (>25km away). In the absence of accurate information, surveillance designs and emergency response plans (including translocation protocols) assume a disease spread distance of 5NM (<10km) to define epidemiological units for all water bodies (see Figure 1). That uncertainty causes policy makers to take a conservative approach. Consequently there is a need to improve the accuracy of predictive information used to manage such aquatic disease incursions. Aim: Model the dispersal of Ostreid herpesvirus (OsHV-1) particles from various locations around South Australia to determine epidemiological units aimed at improving surveillance, biosecurity zoning and future emergency responses. This project aligns with two key objectives of Australia’s National Strategic Plan for Aquatic Animal Health (AQUAPLAN 2014-2019): (1) Enhance surveillance, and (2) Strengthen emergency disease preparedness and response capability. See http://www.agriculture.gov.au/animal/aquatic/aquaplan. A recent FRDC project (2006/005) demonstrated how various oceanographic data can be incorporated into a hydrodynamic model (e-SA marine system) to map past, present and future ocean conditions. This project proposal will provide a case study for how such a model can predict pathogen spread to underpin improved surveillance designs, effective emergency disease response and appropriate biosecurity zoning for translocation protocols.
1. To model viral particle dispersal at key locations around the State, including commercial oyster growing areas, known feral oyster populations and ports, and incorporating seasonal oceanographic parameters
2. Using hydrodynamic model outputs, identify epidemiological units to inform surveillance, disease management and emergency disease response activities
3. Demonstrate how hydrodynamic model outputs of predicted viral particle dispersal can be used to develop a risk-based surveillance design for the detection of OsHV-1