We’re fascinated by how parasites interact with their hosts and the environment, and based in the Odum School of Ecology at the University of Georgia, we study host-parasite interactions within hosts, in populations and communities, and comparatively at the macroecology scale.
We focus on ecological, evolutionary, and mathematical modeling techniques to explore
Epidemiology and Modeling of Infectious Diseases
• Anticipating Epidemics: Research explores general methods for anticipating tipping points in complex systems, estimating the distance to an epidemic threshold, and utilizing early warning signals for both emergence and elimination. This includes studying the statistics of epidemic transitions.
• Disease Emergence and Spread: Studies analyze the waiting time to infectious disease emergence, and how factors like trip duration can modify the spatial spread of diseases.
• Ebola Virus: Several publications are dedicated to the Ebola epidemic, addressing case dynamics and health system demand in Liberia, the spatial spread of the West Africa epidemic, the potential for sexual transmission to compromise control measures, and the spatiotemporal fluctuations and triggers of spillover events. Research also involved fitting multi-type branching process models to Ebola data.
• Influenza Dynamics: The sources cover the dynamic patterns of avian and human influenza in East and Southeast Asia, the evolutionary emergence of pandemic influenza, and quantifying the impact of immune escape on transmission dynamics. Recent work also examines evidence of influenza A (H5N1) spillover infections in horses in Mongolia.
• Control Strategies: Modeling is used to assess when quarantine is a useful control strategy for emerging infectious diseases, and to explore how post-pandemic changes in population immunity might reduce the likelihood of emergence of zoonotic coronaviruses.
Equine Influenza and Vaccination
• Vaccine Efficacy and Optimization: Research focuses on optimizing vaccination strategies in EI and maximizing the benefits of vaccination.
• Strain Variation: Studies investigated the effects of strain heterology (differences between circulating strains and vaccine strains) on EI epidemiology in vaccinated populations. This work also supported the inclusion of strains from both co-circulating lineages of H3N8 equine influenza virus in vaccines.
• Modeling EI: The broader modeling work covers epidemiology, vaccination, spatial spread, and strain variation in equine influenza.
Parasite Ecology, Host Range, and Evolution
• Host Range and Specificity: Research characterizes the phylogenetic specialism-generalism spectrum of mammal parasites, determines what food web structure selects for parasite host range, and explores methods for estimating and predicting parasite host range.
• Costs of Generalism: Studies explore the costs of parasite generalism revealed by abundance patterns across mammalian hosts.
• Impacts of Extinction and Invasion: The concept of the “ghost of hosts past” is explored, examining how host extinction impacts parasite specificity. Relatedly, studies look at patterns of host-parasite coinvasion which can promote enemy release and specialist parasite spillover. Evidence is also found for the Vacated Niche Hypothesis in parasites of invasive mammals.
• Evolutionary Dynamics: Work investigates the interactions between parasites and deleterious mutations, influencing the evolutionary maintenance of sex. Studies also explore how unpredictable environments (environmental stochasticity) help restore competitive balance between sexually and asexually reproducing populations.
• Refugia and Resistance: A critical area is understanding drug resistance, particularly the role of refugia (areas where parasites are not exposed to drugs) in the evolutionary epidemiology of drug resistance.
Vector-Borne and Zoonotic Diseases
• Vector Communities and Prevalence: Research demonstrates that vector species richness can increase hemorrhagic disease prevalence, particularly by functional diversity modulating the duration of seasonal transmission.
• Hemorrhagic Disease (HD) and Climate: Studies analyze wetland cover dynamics as a driver of hemorrhagic disease patterns in white-tailed deer and note the apparent increase of reported HD in the Midwestern and Northeastern USA.
• Environmental Transmission: The importance of environmental transmission in infectious disease dynamics, particularly in animal metapopulations, is highlighted. Recent work shows that abiotic and biotic factors jointly influence the contact and environmental transmission of a generalist pathogen.
• Zoonotic Potential: Research suggests that phylogenetic aggregation increases the zoonotic potential of mammalian viruses.