Exploring the diversity of infectious diseases
We are interested in variation in pathogens and the disease they cause.
How and why did this variation this arise? What are the consequences on this variation for host and ecosystem health?
Read on to understand more about current research themes, study systems and approaches.
Pathogen
life history
traits
Infection
dynamics
(or the course of an infection)
Host immune response regulation & organization
Pathogens exhibit an array of "lifestyles" and induce a variety of effects on their hosts, from the sniffles to castration to hemorrhagic fever. What underlies this variation? When and why should pathogens use one strategy vs. another?
By studying natural variation among pathogens, and the ecological conditions under which different phenotypes arise, we seek to explain some of this astonishing variation. We are particularly interested in variation in host resource acquisition traits and their relationship with virulence (the harm pathogens do to their hosts), as well as drug resistance.
Understanding how variation in pathogen traits arises could help us to predict or even alter pathogen evolution for the good of human and animal health. Furthermore, by understanding pathogen resource use we can shed light on how infectious diseases impact the functioning of ecosystems.
Most of us know from personal experience that the course of an infection can vary greatly among individuals, even when those individuals are infected with the same pathogen (consider your family & friends' different experiences of COVID-19).
By quantifying the factors that control pathogen growth and symptoms (e.g., the availability of host resources that pathogens need to grow, pathogen-killing immune activity), through time we seek to explain variation in infection dynamics. We achieve this through a combination of high-resolution time-series data and mathematical models.
Understanding the determinants of an infection's course could help us to explain why some hosts get sick and others don't, and even predict the course of an individual's infection. The latter marks an essential step in the development of personalized medicine.
The immune response is an intricate defense system comprised of myriad cell types, proteins and signaling molecules. How, as a whole system, is it organized and what is the logic that underlies its deployment?E.g., does pathogen-killing activity grow in response to pathogen number, growth rate or the amount of disease the host is experiencing? Does the host treat infection as a unique perturbation or simply a large change in homeostasis?
By combining experimental perturbations of both pathogen population growth and host homeostasis with mathematical models, we aim to test hypotheses about the organizing principles of the immune system.
Understanding how the immune response is structured and deployed could help us to design new immunotherapies, as well as understand the evolution of `pathogen counter-defenses.
Daphnia are small, globally-distributed invertebrates that are essential to the cycling of resources in aquatic ecosystems and are a longstanding model organism in evolutionary biology, toxicology and, increasingly, biomedicine. They are subject to infection by a variety of pathogens, which occur in MSU's local area.
For these reasons, Daphnia and their parasites are a highly tractable system with which to study evolutionary dynamics and host-parasite-resource interactions. In particular, because it is easy to see offspring and pathogens developing inside the transparent Daphnia, and their pathogens readily transmit in the laboratory, this system is ideal for studying host/pathogen fitness (and hence evolution).
We are developing methods to a) study within-host dynamics using this system and b) perform experiments at high throughput, so that it can be used to explore how interactions between a single host and pathogen scale to epidemic and ecosystem dynamics.
Bacterial pathogens of zooplankton
Malaria parasites are a hugely diverse group of protozoan parasites, the human species of which infect millions of people a year and kill hundreds of thousands. As a result, much is known about i) their ecology & evolution, and ii) their biochemistry, immunology and treatment. On the other hand, the physiology and immunity of mice is incredibly well understood.
For these reasons, the mouse model of malaria represents a highly tractable system with which to investigate the impact of parasite trait variation on within-host dynamics, as well as the regulation of the vertebrate immune system. In particular, this system gives us the ability to precisely manipulate parasite and host traits and cellular population dynamics.
We are further integrating molecular approaches used in biomedical studies of human malaria, with the organismal perspective of eco-evolutionary biology, to use this system to better variation in individual host health and pathogen traits.
Malaria parasites of
rodents
Study systems
