My research focuses jointly on the life history traits and life cycle of the apicomplexan parasite, Monocystis sp., and the population genetics of its host, the invasive “crazy snake worm” (Amynthas agrestis).
Monocystis sp. is a gregarine parasite that infects seemingly all earthworm species and can reach prevalence of up to 100%. The putative mode of transmission of Monocystis is horizontal, with new infections established after infectious sporocysts are consumed by a new earthworm host. Transmission theory tells us that in order to reach 100% prevalence, both horizontal and vertical transmission transmission are required to infect all susceptible individuals even as prevalence increases. But how can a horizontally transmitted parasite that produces relatively few infectious cells infect entire populations?
My current study aims to identify the mode(s) of transmission in different populations that exhibit variable life history traits and determine whether this disease system is concordant with transmission theory. I am using a combination of classical microscopy, real-time PCR, and sequencing to determine the prevalence and rate of vertical and horizontal transmission of this ubiquitous but elusive parasite.
It is important to understand the dynamics of the host population when studying the parasite; therefore, I also work with microsatellites to determine the population genetic structure of populations of the”crazy snake worm”. Are populations of these invasive earthworms from a single inoculum or multiple? Are they spreading due to their own dispersal ability or through the anthropogenic movement of soils? Studies of the population genetics of Amynthas agrestis may shed light on their dispersal, origins, and mating system.