With the emergence of AVG in in Victorian abalone in 2005/6, the subsequent discovery of several genetic variants of the causative agent, abalone herpesvirus (AbHV), associated with disease outbreaks in Tasmanian processing plants, and apparent variations in AbHV pathogenicity observed in different abalone species, there is the need to understand what factors promote disease in infected hosts. This project aims to address this knowledge gap and is relevant to all jurisdictions with abalone fisheries. Access to biosecure aquarium facilities, major abalone species and all known AbHV genotypes provides CSIRO-AAHL with a unique capability to investigate what factors influence disease outcomes following infection, including the nature of the AbHV genotype as well as abalone species or origins from locations spanning the primary wild fisheries in Victoria, Tasmania and South Australia. An improved understanding of the susceptibility of of abalone of different species and origins to infection by the various AbHV genotypes, and of whether different genotypes vary in their potential to transition from sub-clinical infection to acute disease is important for instructing fisheries and aquaculture policies and strategies to avoid disease, especially in aquaculture and abalone processing facilities. This project addresses specific priorities detailed in the current FRDC Aquatic Animal Health Subprogram R&D Plan (viz. 6.2.1 Nature of disease and host-pathogen interaction), priorities identified in the National Abalone Health Work Plan developed by a committee of national representatives following the second Abalone Virus Scientific and Management Forum held in Melbourne in 2007, and FRDC’s 2013 Annual Competitive Round Call for Expressions Of Interest (viz. Determining risk factors for AVG).