Could rats pose a health risk for people living in Vancouver's Downtown Eastside? Understanding the ecology of rats and rat-associated zoonoses in an inner-city neighbourhood.

Urban rats (Rattus spp.) are an important source of zoonotic pathogens, yet there is a paucity of integrated, interdisciplinary, ecosystem-based research on rat-associated zoonoses (RAZ). The goal of this project was to begin to characterize the public health risks associated with rats by studying the ecology of rat populations and the zoonotic pathogens that they carry in an inner-city neighbourhood of Vancouver, Canada. By characterizing rat populations within our study area, we were able to identify a number of factors which could influence the ecology of RAZ. We were also able to design a tool to predict rat abundance based on characteristics of the urban microenvironment, which may be useful for predicting RAZ prevalence in the future. Although we found that L. interrogans (a common RAZ) was present in our study area, other zoonoses thought to be endemic in rat populations worldwide (Seoul hantavirus, Rickettsia typhi, and Bartonella spp.) were conspicuously absent. However, rats were found to carry other potentially zoonotic organisms (Clostridium difficile and methicillin-resistant Staphylococcus aureus) for which they are not the ‘traditional’ reservoir. Finally, we found that by integrating data regarding rat ecology and RAZ, we were able to gain a more comprehensive picture of how these pathogens circulate within rat populations. Overall, this research illustrates the importance of a comprehensive and holistic approach for obtaining a better understanding of RAZ, and highlights the need for ongoing research and surveillance.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat