Host Specificity 

Host specificity, the degree to which a parasite exploits different host species, is one aspect of the host-parasite interface that has been implicated as a factor in shaping parasite population structure and genetic diversity at both fine and regional scales.  I use co-structure analysis to examine the effects of host specificity on the generalist parasite Renifer aniarum and R. ancistrodontis watersnakes (Nerodia spp.) and Cottonmouths (Agkistrodon piscivorous).

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Habitats, Hosts and Parasite Transmission

River networks are habitats characterized by repeated, arborescent bifurcations that form landscape pathways of branches and nodes.  The spatial hierarchy of  headwaters, tributaries, reaches and drainage basins combined with additional physical barriers and unidirectional stream flow can be major determinants of population connectivity and community structure for hosts.  However, little is known about how these features combined with host dispersal can influence parasite transmission and mating system dynamics within river networks.  I examined the effects of network structure in R. aniarum population connectivity in the Colorado River.  Future work will focus on fine-scale transmission and mating system dynamics of the Monogenean parasite Gyrodactylus turnbulli in Trinidandian rivers.  

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Host Heterogeneity and Shoaling Behavior 

Variation in within host processes such as shoaling behavior and individual immune response to parasite infection have the potential to alter both parasite infrapopulation composition (all the parasites in the same species that inhabit a given host individual) and transmission dynamics between hosts.  For Gyrodactylid parasites, which can complete their life cycle on a single host and exhibit continuous transmission among developmental stages, host heterogeneity is likely to have a significant impact on fine-scale patterns of parasite transmission within host shoals and potentially shape parasite mating system dynamics within a host.  More to come- this project is still in development!

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Endemic to Epidemic Parasite Transmission 

The transition from an endemic parasitic infection to an epidemic infection is not well understood.  Sarcoptic mange is caused by a parasitic mite endemic to many wildlife populations.  Recently however, infections of mange in Pennsylvania bears has reached epidemic proportions, resulting in a significant increase in mange-related bear mortality.   In collaboration with the Pennsylvania Game Commission, local Pennsylvania hunters and Jan Janecka at Duquesne University, I am collecting bear and mange samples from southeastern Pennsylvania.  The goal of this project will be to apply molecular epidemiology, landscape resistance genetic simulation modeling and bear population connectivity information in order to better understand the the factors that shift endemic infections to epidemics. 

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Applied Conservation Genetics

Combined with traditional monitoring tools and habitat assessments, population genetic monitoring of endangered and threatened species is an important resource for tracking changes in population connectivity and genetic diversity.  I developed and lead the post-delisting monitoring of the Concho watersnake (Nerodia harteri paucimaculata) using a three prong approach that included genetic, demographic and hydrological data to help preserve this unique Texas endemic.  Past conservation projects focused on the dune sagebrush lizard, black-footed ferret, snow leopard, and Cerulean warbler.  

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