Population dynamics of flaviviruses in the United States

The genus Flavivirus comprises viral species with positive sense, single stranded RNA genomes, most of which are transmitted by mosquitoes and ticks. During replication, RNA viruses have higher mutation rates than DNA viruses, because their virally encoded RNA dependent RNA polymerase has no proofreading activity. These viruses have been shown to exist within and between hosts as swarms of closely related mutant genomes that can be examined through sequence analysis. In the work presented here we focus on the population dynamics of two zoonotic flaviviruses that cause human morbidity and mortality in the United States: tick-borne Powassan virus (POW) and mosquito-borne West Nile virus (WNV). We examine the molecular epidemiology of POW, which has increased in incidence over the past ten years, and exists as two distinct lineages in the United States. We examine the sequence variants in WNV populations in different mosquito tissues to determine the influence of potential bottlenecks within mosquitoes on viral genetic variability. We also test influence of internally deleted WNV genomes isolated from naturally infected birds in NM on virus growth and pathogenesis, both in vitro and in vivo. The primary goal of this work is to develop a better understanding of the underlying evolutionary pressures that influence arbovirus populations and lead to disease emergence.Biomedical SciencesDoctoralUniversity of New Mexico. Biomedical Sciences Graduate ProgramEbel, GregoryHjelle, BrianHanley, KathrynChackerian, BrycePanganiban, Antonit