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oai:mountainscholar.org:10217/2385132025-12-30T03:10:27Zcom_10217_100532com_10217_100000com_10217_100473com_10217_100303col_10217_182111col_10217_100474

Fitzmeyer, Emily Anne, author Ebel, Gregory D., advisor Stenglein, Mark, committee member Kading, Rebekah, committee member Anderson, Brooke, committee member 2024-05-27T10:32:54Z 2025-05-20 2024 Fitzmeyer_colostate_0053A_18314.pdf https://hdl.handle.net/10217/238513 https://doi.org/10.25675/3.02289 Vector competence (VC) refers to the efficiency of pathogen transmission by vectors. Each step in infection of a mosquito vector constitutes a barrier to transmission that may impose bottlenecks on virus populations. West Nile virus (WNV) is maintained by multiple mosquito species with varying VC. However, the extent that bottlenecks and VC are linked is poorly understood. Similarly, quantitative analyses of mosquito-imposed bottlenecks on virus populations are limited. We used molecularly barcoded WNV to quantify tissue-associated population bottlenecks in three variably competent WNV vectors. Our results confirm strong population bottlenecks during mosquito infection that are capable of dramatically reshaping virus population structure in a nonselective manner. In addition, we found that mosquitoes with differing VC uniquely shape WNV population structure: highly competent vectors are more likely to contribute to the maintenance of rare viral genotypes. These findings have important implications for arbovirus emergence and evolution. The mosquito midgut functions as a key interface between virus and vector. However, studies of midgut physiology and associated virus infection dynamics are scarce, and in Culex tarsalis - the primary vector of West Nile virus (WNV) in the contiguous United States - nonexistent. We performed single-cell RNA sequencing on dissociated, WNV-infected Cx. tarsalis midguts. We identified populations of distinct midgut cell-types consistent with existing descriptions of insect midgut physiology and found that all midgut cell populations were permissive to WNV infection. However, we observed high levels of viral RNA suggesting enhanced replication in enteroendocrine cells and cells enriched for mitochondrial genes. In addition, we found no significant upregulation of mosquito immune genes associated with WNV infection at the whole-midgut level, rather, a significant positive correlation between immune gene expression and WNV viral RNA load at the individual cell level. These findings illuminate the midgut infection dynamics of WNV, providing insight into cell-type specific enhancement of, and immune response to, WNV infection in a primary vector. born digital doctoral dissertations English eng Colorado State University. Libraries 2020- Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. vector biology infectious disease virus evolution Linking mosquito midgut and virus population biology at the molecular and cellular level Text 2025-05-20 2025-05-20 This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). Doctor of Philosophy (Ph.D.) Doctoral Microbiology, Immunology, and Pathology Colorado State University open.access