4. Conclusions and Recommendations
The wildlife−domestic interface defines if and how infectious diseases will spread between wildlife and domestic populations. Understanding of this interface involves detailed field studies on the context and nature of interactions between populations. Such knowledge can be incorporated into disease spread models to understand how diseases might behave at the wildlife−domestic interface. Specifically, quantitative estimation of contact rates permits such disease spread models to be developed and used confidently.
Over a period of 10 years, free-roaming domestic dogs and wild dogs in the Northern Peninsula Area (NPA) were studied with the objective of understanding the potential consequences of an incursion of rabies in this area, and more broadly in northern Australia. Key epidemiological findings included identification of a small but important group of domestic dogs which regularly roam in bushland areas; peri-urban wild dog activity, particularly in the dry season, likely driven by the availability of food sources; and the potential for interaction between hunting dogs and wild dogs in remote areas, particularly during the wet season. Such disease spread pathways must be incorporated into models to realistically represent the potential outcomes of a disease incursion within this ecosystem. Furthermore, these studies have generated quantitative information on home ranges, utilisation distributions, and the overlap in activity of domestic and wild dogs. This information can be used to infer contacts between these two populations and thus model disease spread at the wild−domestic interface.
The roaming behaviour of domestic dogs in northern Australian Indigenous communities is a recognised feature of these communities, and this characteristic is determined by cultural norms as well as structural disadvantage (Brookes et al., 2020; Degeling et al., 2018). Studies on the roaming behaviour of domestic dogs are therefore important as input to disease spread models. Recognition of the heterogeneity in roaming behaviour in these populations presents an opportunity to control disease spread at the wild−domestic interface (Hudson et al., 2016). Strategies to mitigate transmission could focus on restricting movement of domestic dogs to limit potential interactions with wild dogs during risk periods (Ward et al., 2021). However, whether the behavioural characteristic of exploring is specific to certain dogs, and methods to reliably identify “explorer” dogs, are research questions which need to be resolved via low-term monitoring of these populations.
Another strategy would be to reduce the activity of wild dogs around communities. This could be done by restricting access to food sources – for example better fencing of waste disposal sites (Ward et al., 2021). This would have maximum benefit during the dry season. Ongoing monitoring of such sites would generate information on which wild dogs are part of this interface, the relationship between dog activity and resource availability, and whether breeding season is a driver of these contacts, with implications for potential disease spread. This requires more than ad hoc research studies. In addition, studies that employ genetic analysis can provide useful information to develop an understanding of the wild−domestic interface (Bombara et al., 2017a; Gabriele-Rivet et al., 2021c).
Whilst hunting might contribute to the wild−domestic interface, characterising and measuring contacts is problematic. Hunting trips often occur during nocturnal hours, and hunting dogs travel out of sight during hunting activities (Gabriel-Rivet et al., 2019a; Sparkes et al., 2016). Hunters can also sometimes lose their dogs. Therefore, contacts between hunting and wild dogs are difficult to observe, record and measure. To contribute to more realistic disease spread models, more field research is needed to estimate contact rates, and identify when, where and under what circumstances these occur as a result of hunting. For example, roads within otherwise densely vegetated areas might act as potential contact hotspots (Gabriele-Rivet et al., 2021b; Vernes et al., 2001). Additional field methods and study designs are needed to understand such characteristics of the wild−domestic interface.
Disease spread models are valuable to help us understand the wildlife−domestic interface. However, to produce insights that can be used to mitigate the effects of disease spread such models require parameterisation of effective contact, which is defined using fundamental knowledge of the underlying system and field data. We have summarised a decade of research conducted to understand one such interface, the wild−domestic dog interface at one site in northern Australia, for the purposes of exploring the impact of one specific disease, rabies. Further development of disease spread models that focus on this interface is the catalyst needed to generate field data to inform these models and provide a deeper understanding of the wildlife−domestic interface.