My research focuses on characterizing the diversity of tick borne pathogens (arboviral, rickettsial, bacterial, and protozoal) and how such diversity (global, national, and at the population level) influences their perpetuation. My expertise is in molecular epidemiology, which integrates field studies with molecular diagnostics and phylogenic analysis. Such skills lend themselves on an active interest in pathogen discovery, clinical diagnosis, and quantitative measurement of pathogen doses and burdens.
My doctoral thesis research focused on the phylogeography of Babesia microti. I demonstrated that there are multiple subspecies of B. microti, most of which do not appear to be pathogenic to humans; their existence has brought into question much of our understanding of the basic ecology of B. microti, as most studies do not differentiate between the diverse parasites. I also analyzed the population structure of Francisella tularensis on Martha's Vineyard. This work showed that the outbreak of tularemia that started in 2000 on the island was not due to a new introduction but from organisms that had been present, undetected, for many years. It also demonstrated that F. tularensis is being perpetuated on the island in small silent foci, a theoretical concept in disease ecology that is often assumed but rarely proven. I recently revisited the phylogeography of B. microti, because its incidence has dramatically increased across southern New England in the last decade. To analyze the cause of this epidemic, I created new tools to examine the population movement of B. microti in fine detail. My data show that a single genotype has expanded its range across the northeastern United States, replacing the endemic populations and may be responsible for the unexpected rise in human cases. My latest work focuses on determining which hosts are most important to the perpetuation of Lyme disease. To this end I am developing new ultra-sensitive molecular methods to identify the source of the host bloodmeal remnants from questing ticks, thereby enabling me to incriminate the host from which the infection was acquired. This work will enable scientists to develop effective targeted ecological interventions and is broadly applicable to other agents, thereby having the potential to change our understanding of the ecology of every tick-borne pathogen.
Master of Science, Harvard School of Pub Health, USA, 1999