A fully funded PhD scholarship is available via the QUEX scheme, jointly supervised by Associate Professor Jan Engelstaedter (The University of Queensland, Australia) and Dr Ben Longdon (University of Exeter, UK).
Project Description: Ecosystems are constantly faced with a critical environmental hazard: infectious diseases. This is because many pathogens do not only attack a single species but several species within an ecosystem. A major source of emerging infectious diseases in humans, wildlife and agriculture are host shifts, where pathogens jump between host species. To assess ecosystem resilience to the threat of invading pathogens, an in-depth understanding of the dynamics of host range evolution and its consequences is vital. In this project, we will make important steps towards this goal by investigating the interplay between host shift dynamics and host-pathogen coevolution. Host shifts are often studied as purely ecological or epidemiological processes. Conversely, host-pathogen coevolution is typically studied within a single host species. Our proposed research will combine these two aspects into a single framework. This is important because adaptations and counter-adaptations of hosts and pathogens will be a major determinant of the likelihood of a host shift being successful.
Our project will have a theoretical and an experimental component that mutually benefit each other. In the theoretical part, to be performed at UQ under the supervision of Dr Engelstaedter, the PhD candidate will develop mathematical models of ecosystems consisting of several host and pathogen species. The aim of these models is to make predictions for how host-pathogen coevolution is expected to affect a pathogen’s host range, prevalence and how this feeds into the stability of the ecosystem. In the experimental part of the project, to be performed at the University of Exeter under Dr Ben Longdon’s supervision, the PhD candidate will carry out empirical work with bacteriophages (viruses) and their bacterial hosts. This system has many advantages that make high-throughput experimental evolution studies feasible, and the phage has a broad host range (infecting several Staphylococcus species) that makes it ideally suited to study host shifts. The experiments will be the first to investigate how coevolution with their hosts will affect a pathogen’s ability to infect other hosts. The experiments will also test whether coevolution with a pathogen will affect a host’s susceptibility to new pathogens.
Our project is expected to make major contributions to our understanding of the factors underlying pathogen host shifts between species in an ecosystem. This in turn will help us understand and ultimately predict the emergence of infectious diseases. Staphylococcus species are important pathogens of both humans and livestock. The phage we will use has been isolated for use in phage therapy, and so by carrying out fundamental research into its host range, we will examine what determines it host range and trade-offs in infectivity between host species, which is ever important in a world with drug resistant infections.
For more information about this scholarship and how to apply, please visit https://scholarships.uq.edu.au/scholarship/quex-phd-scholarship. Informal inquiries are also welcome, please send an email to [Email Address Removed] and/or [Email Address Removed]. The application deadline is 30 August 2022.