Researchers at the USGS are working on developing new quantitative methods to study disease dynamics in wildlife systems as well as systems at the wildlife-domestic-human interface. Much of our work focuses on how host population structure affects disease invasion, persistence and control in wildlife disease systems. We tackle these issues with a combination of simulation and statistical modeling approaches.
Below are publications associated with this project.
Contact and contagion: Probability of transmission given contact varies with demographic state in bighorn sheep
Understanding both contact and probability of transmission given contact are key to managing wildlife disease. However, wildlife disease research tends to focus on contact heterogeneity, in part because the probability of transmission given contact is notoriously difficult to measure. Here, we present a first step towards empirically investigating the probability of transmission given...
Authors
Kezia R. Manlove, E. Frances Cassirer, Raina K. Plowright, Paul C. Cross, Peter J. Hudson
Unraveling the disease consequences and mechanisms of modular structure in animal social networks
Disease risk is a potential cost of group living. Although modular organization is thought to reduce this cost in animal societies, empirical evidence toward this hypothesis has been conflicting. We analyzed empirical social networks from 43 animal species to motivate our study of the epidemiological consequences of modular structure in animal societies. From these empirical studies, we...
Authors
Pratha Sah, Stephan T. Leu, Paul C. Cross, Peter J. Hudson, Shweta Bansal
Inferring infection hazard in wildlife populations by linking data across individual and population scales
Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit...
Authors
Kim M. Pepin, Shannon L. Kay, Ben D. Golas, Susan A. Shriner, Amy T. Gilbert, Ryan S. Miller, Andrea L. Graham, Steven Riley, Paul C. Cross, Michael D. Samuel, Mevin Hooten, Jennifer A. Hoeting, James O. Lloyd-Smith, Colleen T. Webb, Michael G. Buhnerkempe
Disease introduction is associated with a phase transition in bighorn sheep demographics
Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical...
Authors
Kezia Manlove, E. Frances Cassirer, Paul C. Cross, Raina K. Plowright, Peter J. Hudson
When environmentally persistent pathogens transform good habitat into ecological traps
Habitat quality plays an important role in the dynamics and stability of wildlife metapopulations. However, the benefits of high-quality habitat may be modulated by the presence of an environmentally persistent pathogen. In some cases, the presence of environmental pathogen reservoirs on high-quality habitat may lead to the creation of ecological traps, wherein host individuals...
Authors
Clint Leach, Colleen T. Webb, Paul C. Cross
Social living mitigates the costs of a chronic illness in a cooperative carnivore
Infection risk is assumed to increase with social group size, and thus be a cost of group living. We assess infection risk and costs with respect to group size using data from an epidemic of sarcoptic mange (Sarcoptes scabiei) among grey wolves (Canis lupus). We demonstrate that group size does not predict infection risk and that individual costs of infection, in terms of reduced...
Authors
Emily S. Almberg, Paul C. Cross, Andrew P. Dobson, Douglas W. Smith, Matthew C Metz, Daniel R. Stahler, Peter J. Hudson
Assembling evidence for identifying reservoirs of infection
Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in...
Authors
Mafalda Viana, Rebecca Mancy, Roman Biek, Sarah Cleaveland, Paul C. Cross, James O. Lloyd-Smith, Daniel T. Haydon
Utility of R0 as a predictor of disease invasion in structured populations
Early theoretical work on disease invasion typically assumed large and well-mixed host populations. Many human and wildlife systems, however, have small groups with limited movement among groups. In these situations, the basic reproductive number, R0, is likely to be a poor predictor of a disease pandemic because it typically does not account for group structure and movement of...
Authors
Paul C. Cross, Philip L. Johnson, James O. Lloyd-Smith, Wayne M. Getz
Duelling timescales of host mixing and disease spread determine invasion of disease in structured populations
The epidemic potential of a disease is traditionally assessed using the basic reproductive number, R0. However, in populations with social or spatial structure a chronic disease is more likely to invade than an acute disease with the same R0, because it persists longer within each group and allows for more host movement between groups. Acute diseases ‘perceive’ a more structured host...
Authors
P.C. Cross, James O. Lloyd-Smith, P.L.F. Johnson, W.M. Getz
Should we expect population thresholds for wildlife disease?
Host population thresholds for invasion or persistence of infectious disease are core concepts of disease ecology, and underlie on-going and controversial disease control policies based on culling and vaccination. Empirical evidence for these thresholds in wildlife populations has been sparse, however, though recent studies have narrowed this gap. Here we review the theoretical bases for...
Authors
James O. Lloyd-Smith, P.C. Cross, C.J. Briggs, M. Daugherty, W.M. Getz, J. Latto, M. Sanchez, A. Smith, A. Swei
Researchers at the USGS are working on developing new quantitative methods to study disease dynamics in wildlife systems as well as systems at the wildlife-domestic-human interface. Much of our work focuses on how host population structure affects disease invasion, persistence and control in wildlife disease systems. We tackle these issues with a combination of simulation and statistical modeling approaches.
Below are publications associated with this project.
Contact and contagion: Probability of transmission given contact varies with demographic state in bighorn sheep
Understanding both contact and probability of transmission given contact are key to managing wildlife disease. However, wildlife disease research tends to focus on contact heterogeneity, in part because the probability of transmission given contact is notoriously difficult to measure. Here, we present a first step towards empirically investigating the probability of transmission given...
Authors
Kezia R. Manlove, E. Frances Cassirer, Raina K. Plowright, Paul C. Cross, Peter J. Hudson
Unraveling the disease consequences and mechanisms of modular structure in animal social networks
Disease risk is a potential cost of group living. Although modular organization is thought to reduce this cost in animal societies, empirical evidence toward this hypothesis has been conflicting. We analyzed empirical social networks from 43 animal species to motivate our study of the epidemiological consequences of modular structure in animal societies. From these empirical studies, we...
Authors
Pratha Sah, Stephan T. Leu, Paul C. Cross, Peter J. Hudson, Shweta Bansal
Inferring infection hazard in wildlife populations by linking data across individual and population scales
Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit...
Authors
Kim M. Pepin, Shannon L. Kay, Ben D. Golas, Susan A. Shriner, Amy T. Gilbert, Ryan S. Miller, Andrea L. Graham, Steven Riley, Paul C. Cross, Michael D. Samuel, Mevin Hooten, Jennifer A. Hoeting, James O. Lloyd-Smith, Colleen T. Webb, Michael G. Buhnerkempe
Disease introduction is associated with a phase transition in bighorn sheep demographics
Ecological theory suggests that pathogens are capable of regulating or limiting host population dynamics, and this relationship has been empirically established in several settings. However, although studies of childhood diseases were integral to the development of disease ecology, few studies show population limitation by a disease affecting juveniles. Here, we present empirical...
Authors
Kezia Manlove, E. Frances Cassirer, Paul C. Cross, Raina K. Plowright, Peter J. Hudson
When environmentally persistent pathogens transform good habitat into ecological traps
Habitat quality plays an important role in the dynamics and stability of wildlife metapopulations. However, the benefits of high-quality habitat may be modulated by the presence of an environmentally persistent pathogen. In some cases, the presence of environmental pathogen reservoirs on high-quality habitat may lead to the creation of ecological traps, wherein host individuals...
Authors
Clint Leach, Colleen T. Webb, Paul C. Cross
Social living mitigates the costs of a chronic illness in a cooperative carnivore
Infection risk is assumed to increase with social group size, and thus be a cost of group living. We assess infection risk and costs with respect to group size using data from an epidemic of sarcoptic mange (Sarcoptes scabiei) among grey wolves (Canis lupus). We demonstrate that group size does not predict infection risk and that individual costs of infection, in terms of reduced...
Authors
Emily S. Almberg, Paul C. Cross, Andrew P. Dobson, Douglas W. Smith, Matthew C Metz, Daniel R. Stahler, Peter J. Hudson
Assembling evidence for identifying reservoirs of infection
Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in...
Authors
Mafalda Viana, Rebecca Mancy, Roman Biek, Sarah Cleaveland, Paul C. Cross, James O. Lloyd-Smith, Daniel T. Haydon
Utility of R0 as a predictor of disease invasion in structured populations
Early theoretical work on disease invasion typically assumed large and well-mixed host populations. Many human and wildlife systems, however, have small groups with limited movement among groups. In these situations, the basic reproductive number, R0, is likely to be a poor predictor of a disease pandemic because it typically does not account for group structure and movement of...
Authors
Paul C. Cross, Philip L. Johnson, James O. Lloyd-Smith, Wayne M. Getz
Duelling timescales of host mixing and disease spread determine invasion of disease in structured populations
The epidemic potential of a disease is traditionally assessed using the basic reproductive number, R0. However, in populations with social or spatial structure a chronic disease is more likely to invade than an acute disease with the same R0, because it persists longer within each group and allows for more host movement between groups. Acute diseases ‘perceive’ a more structured host...
Authors
P.C. Cross, James O. Lloyd-Smith, P.L.F. Johnson, W.M. Getz
Should we expect population thresholds for wildlife disease?
Host population thresholds for invasion or persistence of infectious disease are core concepts of disease ecology, and underlie on-going and controversial disease control policies based on culling and vaccination. Empirical evidence for these thresholds in wildlife populations has been sparse, however, though recent studies have narrowed this gap. Here we review the theoretical bases for...
Authors
James O. Lloyd-Smith, P.C. Cross, C.J. Briggs, M. Daugherty, W.M. Getz, J. Latto, M. Sanchez, A. Smith, A. Swei