Evolutionary theory predicts that parasites will plastically change their life history traits in the face of a changing environment, yet the extent to which parasites do so is just beginning to be understood. My research integrates parasite ecology and population genetics to deduce factors influencing the evolution of parasite infection dynamics and subsequent transmission potential. For the past eight years, I have studied how within-host diversity of malaria parasites (also termed multi-clonal infections) can alter the parasite’s growth inside the vertebrate host, its virulence and transmission efficiency.
My current research interests lie in elucidating the transmission cycle of the lizard malaria parasite, Plasmodium mexicanum. Stemming from my dissertation research with Dr. Joseph Schall at the University of Vermont, I will address questions relating to parasite infection dynamics over multiple seasons, transmission intensity throughout the summer and the population genetics of the vectors. These foundational studies will shed light upon the patchy infection patterns we see at our field site.
My postdoctoral research focused on the effects of vector control programs and drug choice on the infection and transmission dynamics of Plasmodium falciparumin the west Kenyan Highlands. Although vector control measures, and more recently a new drug policy focusing on Artemisinin combination therapies, have successfully reduced transmission of the parasite in these areas, studies examining the parasite’s response to such reductions in transmission are scarce and necessary. I utilized cohort based studies to examine how fewer transmission opportunities affect parasite density, prevalence, and gametocyte carriage. I also examined how quickly the selection pressure for “outdated” drugs would be lifted once a new drug regimen is prescribed.
My doctoral research focused on the lizard malaria parasite, Plasmodium mexicanum, and its hosts the lizard, Sceloporus occidentalis, and sandfly vectors, Lutzomyia vexator and L. stewarti. I used recently characterized microsatellite markers to elucidate what effects multiple infections have on the parasite’s growth, transmission and virulence. I found that multiclonal infections do alter the infection dynamics and virulence of P. mexicanuminfections, but does not appear to affect transmission success. Additionally, I found that the majority of clones within an infection successfully transmitted to the vector and produced oocysts. This suggests that a major transmission bottleneck does not occur during the transmission from the lizard to the vector-the majority of parasite clones successfully make it into the vector, reproduce and form oocysts. The transmission from vector back to lizard however, has not yet been examined. This work has laid the foundation for the studies I propose to conduct as a faculty member at Penn State York.
Master’s Degree Research:
I obtained my Master’s Degree in Marine Biology from the University of Massachusetts, Dartmouth, under the supervision of Dr. Ronald A. Campbell. My research examined the tapeworm assemblages found in sharks, skates and rays (elasmobranchs) from the Eastern Atlantic. With a primary focus on the tapeworm genus Acanthobothrium, we discovered 5 news species from 5 different hosts- 2 of which are new hosts for tapeworms belonging to this genus. The Genus Acanthobothrium may be one of the more diverse genera of tapeworms, with over 200 species and counting.