Key Areas of Research
The Plowright Lab works collaboratively to tackle the complex challenges of zoonotic disease emergence.
We integrate knowledge and expertise across many disciplines and work at scales spanning molecules to landscapes. We collaborate with teams around the world to conduct long-term field studies, laboratory analyses, and modeling. This deep integration across different disciplines and knowledge frameworks allows us to pursue vexing problems such as how planetary scale environmental change drives local processes, including zoonotic spillover.
Projects undertaken by the lab are shaped by the following questions:
How do pathogens cross species barriers to cause a spillover event?
How do environmental stressors, including land-use change and climate change, drive the dynamics of pathogens within reservoir host populations and risk of spillover to other species?
How can we prevent pandemics by preventing spillover?
What is the best way to implement our science for protection of ecosystem, wildlife, and human health?
Q1: How do pathogens cross species barriers to cause a spillover event?
Spillover is achieved when a pathogen is able to breach a series of barriers to pass from one host species to another (from Plowright et al. 2017).
Recent pandemics, including COVID-19, are a consequence of viral spillover. We developed a conceptual model of the spillover process that demonstrates how pathogens percolate from reservoir hosts to humans through a series of barriers that can be breached through circumstance. The probability of spillover is determined by a sequential and non-linear interaction among processes that span viral protein structure at 10-9 m to reservoir host ecology at 105 m. We are working on henipaviruses and coronaviruses in Australia and Bangladesh to understand the conditions that allow viruses to spillover from bats to humans or human-associated species.
Q2: How do environmental stressors, including land-use change and climate change, influence pathogens within reservoir host populations and risk of spillover to other species?
Land use-induced spillover
Land use-induced spillover process (from Plowright et al. 2021)
Conceptually, ecological disruption is recognized as the primary driver of zoonotic pathogen spillover from wildlife to human populations. However, the mechanisms by which ecological disruption triggers the cascade of events leading to spillover are little studied, and rarely with transdisciplinary research. Ecological disruption operates at many scales, from molecular interactions that determine host immune responses to landscape-level interactions that determine food availability. We are collecting the empirical data necessary to move understanding from pattern to process and mechanism.
For example, we recently published work detailing 25 years of data derived from studying the large, nectar-feeding bats that host Hendra virus – a virus found in Australia that spills over from bats to horses, then from horses to humans. We showed that habitat loss, interacting with climate variation, drives clusters of spillover events that can be predicted and prevented. Spillover events could be stopped by replanting the forests that feed bats nectar in winter. (See associated media, below).
Based on these studies, and others, we are trying to delineate generalizable theories of how changes in land use influence spillover risks. We recently developed the hypothesis of land use-induced spillover to explain how pathogen shedding and wildlife-human contact drive emergence of zoonotic disease in the context of ecological disruption. We are investigating the ecological decision points that would suggest that ecological restoration and protection can protect human health.
Pathogen dynamics in reservoir host populations
The risk of zoonotic spillover from animals to people is a function of the spatial and temporal distribution of infection in reservoir host populations. Therefore, understanding the drivers of these distributions is critical to predicting spillover risk. We have a major transdisciplinary effort underway with physiologists, immunologists, ecologists, behavior experts, virologists, veterinarians, social scientists, epidemiologists, mathematical modelers, machine learning experts, and environmental scientists to understand the drivers of viral excretion (and spillover) from bat populations. Our team has ongoing projects sampling bat populations over time and space in Australia, Bangladesh, and Ghana. We are collecting extensive metadata on bat health and environmental conditions.
Our work has demonstrated that bat populations excrete viruses in brief, spatially and temporally discrete pulses that coincide with periods of environmental stress, and multiple viruses are shed synchronously during these events. We have manuscripts in preparation describing the dynamics of henipaviruses and coronaviruses.
Select media coverage of Eby et al. 2023:
Deforestation Brings Bat-Borne Virus Home to Roost.
By Emily Anthes, November 16, 2022.
Habitat loss and climate change increase the risk of new diseases.
Graphic detail section. January 31, 2023.
9 diseases that keep epidemiologists up at night.
By Sheila Mulrooney Eldred, January 29, 2023.
Le renard volant éclaire l’émergence des pandémies.
By Nathaniel Herzberg, January 5, 2023.
Hendra virus rarely spills from animals to us. Climate change makes it a bigger threat.
By Ari Daniel, November 16, 2022.
Giving a bat flowers might preempt a pandemic.
By Justine Calma, November 16, 2022.
Q3: How can we prevent pandemics by preventing spillover?
The transdisciplinary approach to studying pathogen spillover. (Left) We simultaneously collect information on ecology, physiology, behavior, and host–viral dynamics. Data are integrated within models to make predictions and develop interventions to prevent spillover. (Right) Proactive assessment of the pandemic potential of viruses by examining viral fitness in silico, in vitro, and in vivo. From Plowright & Hudson 2021.
Pandemics occur at the nexus of three planetary crises: zoonotic spillover, climate change, and loss of biodiversity. We are developing ecological solutions that address these existential crises while also protecting public health.
Primary pandemic prevention is aimed at stopping the spillover event that triggers the pandemic cascade. Our work has shown that if you understand mechanisms of disease emergence, the solutions to stop spillover become readily apparent.
We recently led a series of international workshops to develop specific strategies to stop spillovers through nature-based approaches (work is in review, watch this space). Some of our results were presented in a June 26th, 2023 webinar, “Reducing the risk of future pandemics requires investment in prevention, preparedness, and response”.
In addition to these lab efforts, Dr. Plowright is co-chair of The Lancet Commission on Prevention of Viral Spillover, to be announced in the Lancet in fall 2023.
Moreover, the BatOneHealth team works to develop the transdisciplinary approach to prevent pandemics. The team combines field, lab, and modeling studies to better understand spillover (see figure below on the Bat One Health approach). Our team has published over 80 collaborative papers to date.
Q4: What is the best way to implement our science for protection of ecosystem, wildlife, and human health?
The epidemiology of bighorn sheep pneumonia caused by Mycoplasma ovipneumoniae (from Plowright et al. 2017)
As part of our National Science Foundation (NSF) Coupled Human-Natural Systems grant, our group worked with grassroots organizations, such as Landcare, and conservation efforts, such as The Great Eastern Ranges, to develop reforestation strategies to stop spillover. An online, open-access archive of habitat restoration now shows the extent of replanting of bat habitat to encourage bats’ return to nomadism (Habitat Restoration HUB). Our Australian co-PIs successfully lobbied for incorporation of bat habitat into Australian bushfire regeneration and climate resilience programs.
Our NSF Rules of Life grant includes research with social scientists to test the effectiveness of the One Health paradigm as a motivator for nature conservation. Moreover, we are testing various narratives with empirical methods to suggest how we can move humanity towards more proactive responses to pandemics (e.g., stopping the land-use change that drives spillover).
Humans are not the only species affected by spillover. Many of our wildlife species have been devastated by pathogens introduced from elsewhere. Our lab has contributed to the conservation of bats with white-nose syndrome, and the conservation of bighorn sheep with pneumonia. Of note, our work delineated how the decline of western North American bighorn sheep populations has been driven by pneumonia. Our field studies helped identify older ewes as long-term carriers of the causative pathogen, as well as how pneumonia is maintained in populations. This work led to fundamental changes in the way bighorn sheep are managed, and to guidance that has helped eradicate pneumonia from many wild populations..