Date of Award
Summer 8-2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
Program/Concentration
Ecological Sciences
Committee Director
Holly D. Gaff
Committee Member
David T. Gauthier
Committee Member
Wayne L. Hynes
Committee Member
Robert K. Rose
Committee Member
Bryan E. Porter
Committee Member
Jean I. Tsao
Abstract
The Gulf Coast tick, Amblyomma maculatum, is a vector of Rickettsia parkeri, the causative agent of Rickettsia parkeri rickettsiosis. In the United States, A. maculatum has expanded northward from its historic range, with populations establishing in Virginia in 2010. Newly established populations of A. maculatum, including those in Virginia, have a higher prevalence of R. parkeri than populations in the historic range. The persistence of A. maculatum populations with high rates of R. parkeri infection poses a risk to public health. Tick-borne disease dynamics are influenced by interactions between ticks, pathogens, hosts, and the environment. The specific suite of ecological factors that facilitate A. maculatum persistence and contribute to the higher prevalence of R. parkeri in the region are poorly understood. The purpose of this dissertation was to further the understanding of the natural history of A. maculatum and to determine what role the hosts of the immature ticks may play in the higher prevalence of R. parkeri in southeastern Virginia. Long-term surveillance documented the establishment, persistence, and decline of A. maculatum populations and provided the first description of the phenology of all life stages in the region. Many A. maculatum populations were transient, suggesting that long-term persistence may depend upon specific habitat and host requirements. Small mammals were sampled to identify hosts of immature A. maculatum and to evaluate their potential role in the maintenance of R. parkeri, resulting in the largest collection of immature A. maculatum from small mammals reported in the Mid-Atlantic region.
Hispid cotton rats and marsh rice rats were identified as the predominant hosts of the immature life stages. Evidence supporting any rodent species acting as a reservoir host of R. parkeri was limited. Finally, genetic analyses of the white-footed mouse, Peromyscus leucopus, from a local field site were conducted to evaluate whether field observations suggesting morphological similarity to historical descriptions of the Pungo mouse, P. l. easti, correseponded to underlying genetic variation. Analyses of three mitochondrial loci provided no evidence supporting subspecies differentiation. Overall, this work contributes to the understanding of A. maculatum, but more research is needed to fully understand this complex system.
Rights
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DOI
10.25777/m421-3580
Recommended Citation
Espada, Christina D..
"A One Health Approach to Understanding the Natural History of Amblyomma maculatum in Southeastern Virginia"
(2026). Doctor of Philosophy (PhD), Dissertation, Biological Sciences, Old Dominion University, DOI: 10.25777/m421-3580
https://digitalcommons.odu.edu/biology_etds/411