Introduction: Canine rabies, a fatal viral zoonosis, is now less than 300 kilometres from Indonesian archipelago. To respond to this imminent threat, we need to model how rabies will spread through Australian ecosystems, to develop effective rabies management plans. This will improve our chances of minimising reaction times and containing outbreaks. Aims: To quantify contact rates, abundance, population turnover and dog bite frequency, in order to inform models of canine rabies spread. This is essential for identifying critical control points.

Australian remote Aboriginal communities commonly have large, free-roaming dog populations and relatively small cat populations. However, cats are becoming increasingly popular pets in these communities and it is essential to determine their potential impacts on wildlife to inform animal management practices. In a small island community, this study provided baseline population demographics and investigated dog and cat roaming behaviours and interspecific interactions. The dog population, estimated at 343 dogs, showed active periods at dawn and dusk. The cat population had doubled in 6 months to approximately 83 cats. Cats were observed roaming mainly from dawn until dusk, possibly avoiding periods when dogs were most active. The majority of cats were observed nonroaming. Three cats, however, were captured roaming during the night when all flightless wildlife were observed on our camera traps, suggesting potential impact on local wildlife through their hunting activities. These baseline data provide evidence on which to base management programs that include cats and their impacts on native wildlife. Further research using the multiple methods piloted in this study are warranted to monitor dog and cat populations and their interactions in this island community.

Free-roaming dogs ('Canis familiaris') are common worldwide, often maintaining diseases of domestic pets and wildlife. Management of these dogs is difficult and often involves capture, treatment, neutering and release. Information on the effects of sex and reproductive state on intraspecific contacts and disease transmission is currently lacking, but is vital to improving strategic management of their populations. We assessed the effects of sex and reproductive state on short-term activity patterns and contact rates of free-roaming dogs living in an Australian Indigenous community. Population, social group sizes and rates of contact were estimated from structured observations along walked transects. Simultaneously, GPS telemetry collars were used to track dogs' movements and to quantify the frequency of contacts between individual animals. We estimated that the community's dog population was 326±52, with only 9.8±2.5% confined to a house yard. Short-term activity ranges of dogs varied from 9.2 to 133.7 ha, with males ranging over significantly larger areas than females. Contacts between two or more dogs occurred frequently, with entire females and neutered males accumulating significantly more contacts than spayed females or entire males. This indicates that sex and reproductive status are potentially important to epidemiology, but the effect of these differential contact rates on disease transmission requires further investigation. The observed combination of unrestrained dogs and high contact rates suggest that contagious disease would likely spread rapidly through the population. Pro-active management of dog populations and targeted education programs could help reduce the risks associated with disease spread.

Currently, Australia is free from terrestrial rabies but an incursion from nearby Indonesia, where the virus is endemic, is a feasible threat. Here, we aimed to determine whether the response to a simulated rabies incursion would vary between three extant Australian dog populations; free-roaming domestic dogs from a remote indigenous community in northern Australia, and free-roaming domestic and wild dogs in peri-urban areas of north-east New South Wales. We further sought to predict how different management strategies impacted disease dynamics in these populations. We used simple stochastic state-transition models and dog demographic and contact rate data from the three dog populations to simulate rabies spread, and used global and local sensitivity analyses to determine effects of model parameters. To identify the most effective control options, dog removal andvaccination strategies were also simulated. Responses to simulated rabies incursions varied between the dog populations. Free-roaming domestic dogs from north-east New South Wales exhibited the lowest risk for rabies maintenance and spread. Due to low containment and high contact rates, rabies progressed rapidly through free-roaming dogs from the remote indigenous community in northern Australia. In contrast, rabies remained at relatively low levels within the north-east New South Wales wild dog population for over a year prior to an epidemic. Across all scenarios, sensitivity analyses revealed that contact rates and the probability of transmission were the most important drivers of the number of infectious individuals within a population. The number of infectious individuals was less sensitive to birth and death rates. Removal of dogs as a control strategy was not effective for any population modelled, while vaccination rates in excess of 70% of the population resulted in significant reductions in disease progression. The variability in response between these distinct dog groups to a rabies incursion, suggests that a blanket approach to management would not be effective or feasible to control rabies in Australia. Control strategies that take into account the different population and behavioural characteristics of these doggroups will maximise the likelihood of effective and efficient rabies control in Australia.

Rabies is a preventable viral zoonosis that causes inflammation of the brain, and eventually death, in infected mammals. With few exceptions, including Australia, terrestrial rabies can be found worldwide. More than 55,000 deaths from rabies infection are reported annually; these are mainly in Asia and Africa where the primary reservoir is the domestic dog.

Despite ongoing control efforts in Indonesia, canine rabies remains a disease of critical concern there. Although rabies is not endemic in Australia, at less than 300km away in Indonesia, a rabies incursion is a likely and imminent threat.

To improve preparedness for a canine rabies outbreak in Australia, I collected data on a number of extant dog populations in northern and eastern Australia. I used a range of methods including self-administered questionnaires, GPS telemetry collars, camera trapping and mark-recapture studies. Using my own data and parameters collected from the wider literature, I developed state-transition models to determine how rabies could spread through these dog populations. Finally, I used these same models to evaluate a range of control strategies, including dog removal and vaccination, to identify the most effective options for reducing impacts in Australian communities following a rabies incursion.

Model outputs suggested that rabies will progress differently within functionally different dog populations present within Australia. Restrained domestic dogs posed limited risk for rabies transmission, because interactions with other dogs were limited and generally supervised by owners. Free-roaming domestic and hunting dogs will likely play an important role in rabies transmission in some situations only, primarily based on their ability to roam, access to other free-roaming dogs and their interactions within and between dog groups. Wild dogs (including dingoes) proved the most critical type of dog for rabies spread and maintenance in Australia, because they are widely distributed, often in high abundance, roam over large distances and frequently interact.

I found that time to detection for rabies in wild dogs will likely be lengthy, probably due to low infection rates prior to an epidemic and limited contact with humans, relative to the other categories of dog that I studied. Further, the capacity of authorities to implement effective control strategies for wild dogs will likely be restricted because of limited access to individual animals. The economic costs of controlling a rabies outbreak involving wild dogs will be substantial and likely equivalent to the costs for extensive aerially-based wild dog control that are currently used in some areas of Australia (~Aus$34 km-2).

Australia’s current plans to address rabies incursions, which were developed in the 1990s are clearly outdated. My findings reveal that revision of these plans, taking specific account of relevant differences between restrained domestic dogs, free-roaming domestic dogs and extensive wild dog populations is necessary to ensure that Australia is adequately prepared for the arrival of canine rabies.