Lori Stevens

318 Marsh Life Science Building
University of Vermont
Burlington, VT 05405
802-656-0445
lori.stevens@uvm.edu

Professor




Office Hours: Tues and Fri, 11:00 - 12:00

For information on courses go to: Course Information

Research Interests

My research interests: Evolution and ecology of host-pathogen interactions, especially population genetics of hosts of Chagas' disease and whirling disease, computational biology including spatial models of evolution, mathematical biology.

I also direct two undergraduate research mentoring programs: one for Interdisciplinary Training: Math & Biology and one for diversity and inclusion Env-Bio Undergraduate Mentoring Program.

My current research focus is the ecology and evolution of host-pathogen interactions.

Overall Research Objective: Understand the spatial pattern of variation in prevalence of infection by examining the ecological and evolutionary factors that govern the distribution and abundance of pathogens and their hosts.

Organisms are constantly and continuously exposed to harmful pathogens and evolution through natural selection has responded with a myriad of host-parasite interactions. When organisms are exposed to pathogens they might or might not become infected depending on these interactions. The study of infectious pathogens has a rich history, including host-pathogen population dynamics, host specificity, the evolution of virulence, and the costs of resistance and defense.

I investigate the dynamics of host-pathogen interactions using molecular ecology, population genetics complex systems modeling

Chagas disease: Chagas disease, caused by Trypanosoma cruzi, afflicts up to 11 million people in Latin America and causes potentially life-threatening disease in up to one third of those infected. Reducing new infections of Chagas disease ultimately depends on vector control. Knowledge of vector population structure and sources of infesting insects are vital to the success of vector control strategies; however, the extent of population structure, migration between populations, and the source(s) of re-infestation following insecticide application are virtually unknown. We are working to develop a basic understanding of the molecular population genetics of the insect vectors in endemic areas in Bolivia and Guatemala. Our population genetic studied are helpful because vector control efforts require an understanding of migration. Understanding the dynamics of vector population structure will ultimately lead to more effective control of T. cruzi transmission.

The work is done in collaboration with Juan Carlos Pizarro, Universidad de San Francisco Xavier, Sucre, Bolivia, *Patricia Dorn, Loyola University, ND.

Whirling disease: In collaboration with Billie L. Kerans (Montana State University), I am helping to characterize Oligocheate communities to monitor Myxobolus cerebralis infection on the Madison River, MT.

In the 1950's, the fish parasite, Myxobolus cerebralis invaded the US from Europe. The parasite invades cartilagenous skeletal tissue surrounding the brain causing fish to swim in circles, hence the name. Whirling disease has devastated populations of wild rainbow trout (Oncorhynchus mykiss) and is contributing to the decline of Yellowstone cutthroat trout (O. clarki bouvieri). Although M. cerebralis has been detected in watersheds throughout much of the US, the distribution and severity of whirling disease is both regionally and locally variable.

Myxobolus cerebralis has a two-host life cycle alternating between salmonid fish and the oligochaete worm, Tubifex tubifex. We are examining how the introduced parasite affects genetic variation in the invertebrate host, disease incidence in the vertebrate host and ultimately community dynamics.

Complex systems modeling: I work on two types of computational models geneticalgorithms and artificial neural networks. My lab is developing evolutionary algorithms for the evolution of defenses. The work is done in collaboration with Dr. Donna Rizzo (College of Engineering and Mathematical Sciences, UVM). The project examines multi-objective optimization models for the evolution of costly vs cost-free defenses in the context of spatial and temporal variation in pathogen prevalence. The work is applicable to both plant and animal systems.

Information for Prospective Graduate Students:If you are interested in the evolution and ecology of host-parasite interactions from a population genetics perspective and want to do collaborative empirical or theoretical work with insects to rigorously test hypotheses, please contact me via e-mail.

Selected Publications