IMPACTS OF RAPID LANDSCAPE CHANGE AND BIODIVERSITY ON VIRUS HOST SPECIFICITY

Rapid changes to landscapes and the biodiversity of plants and animals are altering relationships between microbes and their natural hosts with direct implications for human health. This study investigates the impacts of deforestation, landscape change, and biodiversity on virus characteristics that determine zoonotic potential, including virus "host plasticity", which is the diversity of host species a virus can infect in nature. Previous work has indicated that higher virus host plasticity is linked to increased likelihood of human-to-human transmission and wider geographic spread. This project seeks to understand whether landscape and biodiversity change drive microbes towards greater host plasticity and therefore heightened pandemic risk. Findings from this research will contribute to ecological theory on the impact of environmental changes on microbial adaptation, with practical implications for management of ecosystems at high risk for pathogen spillover. This research is especially relevant to public authorities seeking evidence on the relationship between environmental change, biodiversity, disease outbreaks, and pandemics. Training opportunities provided through this project will help foster a network of cross-trained scientists interested in disease dynamics, public health and animal health who will strengthen One Health research into the future.

Viruses have more opportunities to adapt to new hosts at the edge of ecosystem boundaries, which could influence virus host plasticity and increase spillover risk as new ecosystem edges are formed through habitat fragmentation. To test this hypothesis, this research investigates the host range of bat-borne coronaviruses and mosquito-borne arboviruses (flaviviruses, alphaviruses and bunyaviruses) across replicated gradients of landscape change and community composition in the biodiverse tropical forests of Southeast Asia. Theoretical and computational modeling, underpinned by field investigations and in vitro experiments, will evaluate (1) how virus host and vector plasticity changes at the edge of ecosystems, such as at the boundary between forest and urban habitats, 2) how virus host plasticity is related to virus epidemiology across landscapes, and 3) how intra-host genetic diversity of viruses is influenced by host and vector plasticity. Data and model driven insights will inform on the role that mosquito vectors play in constraining or expanding virus host plasticity and genetic diversity. Characterization of bat-borne coronaviruses and host affinities in an ecosystem with SARS-CoV-related viruses will further inform on coronavirus evolution and emergence of zoonotic potential. This study explores an important paradigm of functional relationships between biodiversity and public health to advance a mechanistic understanding of zoonotic virus emergence with potential to be generalized to other 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.