Drivers of infection outbreaks in a temperature-sensitive host-pathogen system

Emerging infectious diseases threaten global biodiversity and often exhibit seasonal outbreaks that are linked to temperature. Seasonal temperature variation may shape disease dynamics through a variety of host-related (e.g., behavior, immune response) and pathogen-related (e.g., development, growth) pathways, making it challenging to predict when and how large outbreaks will be. This research project combines lab experiments, field data, and modeling to understand drivers of disease in an amphibian-pathogen system and to make predictions about the size and timing of outbreaks. The employed model is useful across temperature-sensitive disease systems, and the findings within the study system are being incorporated into ongoing amphibian management decisions. The team also is creating a lesson plan on the importance of temperature to disease outbreaks that will be used by the Student Network for Amphibian Pathogen Surveillance, a growing network that integrates classroom learning with student-powered pathogen surveillance. Collectively, the project utilizes a multidisciplinary approach - employing lab experiments, field data, and modeling - to elucidate the relationship between temperature variations and disease dynamics, particularly in amphibians. The research paves the way for better ecological understanding of temperature-sensitive diseases, more informed management decisions, and new educational tools that connect our science with students. This project builds on five years of preliminary data in an amphibian-chytrid system with strong seasonal dynamics and detailed longitudinal infection data on individuals, as well as information about animal movements. The investigators use these field data along with complementary laboratory experiments and the development of a mechanistic model to answer the following four questions: (1) How does host temperature determine in-host pathogen growth? (2) How does host behavior affect the relationship between environmental temperature and host temperature? (3) How does environmental temperature influence pathogen transmission? (4) How do different seasonal temperature profiles affect the timing and magnitude of seasonal disease outbreaks? To make inferences and predictions about the magnitude and timing of seasonal outbreaks, the team is developing a Bayesian implementation of an integral projection model that accounts for imperfect host and pathogen detection and integrates both field and laboratory data. This approach extends our understanding of temperature-sensitive disease systems, such as white-nose syndrome, salamander chytridiomycosis, and snake fungal disease, as well as the general role of temperature in host-pathogen dynamics. This work is funded by the Divisions of Environmental Biology and Integrative Organismal Systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.