E&E Fall 2021 Seminar Series:
Dr. Rachael Kramp
University of Pittsburgh - Stephenson Lab
"Unraveling the role of the microbiome in host-ectoparasite infectious disease dynamics"
Once birthed—and possibly before—animals are rapidly colonized by a diverse community of archaea, bacteria, fungi, viruses, and microeukaryotes: the host-associated microbiome (HAM). HAM has a substantial role in systemic host health and has been implicated in several vital host functions, including but not limited to: autoimmune disease; development; immune education; and vitamin synthesis. Host-microbiome interactions, therefore, have fundamental implications for the ecological and evolution of the host organism.
Traditionally, infectious disease research has focused on non-indigenous organisms, 'pathogens' and 'parasites,' as central to the cause of infectious disease. Postulated initially by Koch, infection occurs in a simple progression: a non-indigenous organism colonizes the host, which causes disease. However, recent global increases in infectious disease prevalence and trans-continental transmission underscore the urgency of developing a more inclusive representation of the factors involved in disease dynamics. My thesis work will expand our understanding of the host-parasite dynamic and test how the indigenous HAM plays a critical role in determining susceptibility to and outcomes of infectious diseases. I will investigate four key factors of the host-HAM-disease interface: host heterogeneity, transmission, parasite fitness, and host behavior. Host heterogeneity—the differences between individual hosts in, for example, defense against parasites—is a vital factor in host-parasite interaction outcomes at the individual and the population level. Genetic factors and the HAM can influence defense and may interact; for example, the host immune response, which is also involved in genetic defense against parasites, may shape the HAM. In an artificial selection experiment using guppies, Poecilia reticulata, we found heritable resistance to Gyrodactylus parasites, as well as that the host skin HAM community before infection was also, independently, correlated with infection severity.
In my current work, I am experimentally manipulating the microbial communities within the rearing water to test the HAM's role in transmission, parasite fitness, and host behavior. Fish are reared in one of three treatment groups consisting of conventional, probiotic and, sterilized water. The conventional treatment is wastewater from adult fish from the same lineage; probiotic is the same wastewater but inoculated with Lactobacillus acidophilus after water changes; and microbial deplete is sterilized water through the autoclave. My preliminary results show reduced body size under microbial deplete conditions.
Wednesday, October 13th, 2021
A219B Langley Hall
12:00 PM