Australia’s Rabies Status: Risk and Mitigation of a Potential Incursion

Abstract

Australia is currently free of canine rabies. However, the communities in the Northern Peninsula Area (NPA), Queensland are at an unknown risk of an incursion because of proximity to rabies infected islands of Indonesia and the presence of large populations of free-roaming dogs capable of maintaining rabies. This thesis used a risk assessment to quantify the risk of rabies entry from Indonesia and estimated an annual probability of 8.3x10-5 that at least one rabies-infected dog could cause rabies transmission. This probability is low but not negligible considering the devastating impacts of rabies on animal and human health. This thesis also collected information on how rabies would spread and what control strategies would best contain a potential outbreak in the NPA. Information on the NPA dog population size and dynamics, which was previously lacking, was collected via sight-resight surveys and dog-owner questionnaires. Similarly, a novel simulation study was developed to analyse GPS data and identified three roaming patterns within the population. The population demographics and the heterogeneous roaming patterns were incorporated into an agent-based rabies-spread model and revealed that dogs that extensively roamed caused large, fast-spreading epidemics compared to dogs that mainly stayed at home. Further, targeted reactive and pre-emptive vaccination of far roaming dogs versus stay-at-home dogs were more effective in reducing simulated outbreak sizes and durations. Overall, this thesis equips decision-makers with actionable information in which pre- and post-border biosecurity policies can be developed or updated. Furthermore, the information in this thesis can be used to direct further studies for both risk mitigation activities or cost-benefit analyses for vaccination strategies. With such information, our ability to reduce the risk of rabies incursions, control rabies outbreaks and improve animal and human welfare is greatly enhanced.