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Forest disturbance, mosquito vector ecology and La Crosse virus dynamics in southwestern Virginia

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dc.contributor.authorHarris, Maria-Richetta Camilleen
dc.contributor.committeechairHawley, Dana M.en
dc.contributor.committeememberPaulson, Sally L.en
dc.contributor.committeememberJones, Robert H.en
dc.contributor.committeememberElvinger, Francois C.en
dc.contributor.committeememberMeng, Xiang-Jinen
dc.contributor.departmentBiological Sciencesen
dc.date.accessioned2016-03-16T06:00:31Zen
dc.date.available2016-03-16T06:00:31Zen
dc.date.issued2014-09-22en
dc.description.abstractThe influence of forest canopy disturbance (FCD) on La Crosse virus (LACV), leading cause of US pediatric arboviral encephalitis, is critical to understand in landscapes where forests are periodically harvested. Southwestern Virginia is part of an emerging focus of this interior forest bunyavirus. I investigated how the temperate forest mosquito community, LACV vectors, and the LACV amplifying vertebrate host (chipmunks) were impacted by logging. This research was conducted across an experimental FCD gradient (from least to most disturbed: contiguous control, fragmented control, clearcut, and high-leave shelterwood (SW)). Using gravid traps, I found that the mosquito community was resilient to logging with no significant difference in diversity or community composition across treatments. Mean number of female mosquitoes caught per trap-night declined with disturbance. FCD significantly affected the abundance of vector species in different ways. The primary LACV vector, Aedes triseriatus, and the recent invasive Ae. japonicus declined with logging. Other vectors (Ae. albopictus, Ae. canadensis, and Ae. vexans) thrived with logging. Culex pipiens/restuans was affected by disturbance but had no treatment preference. A mark-recapture study revealed that chipmunk abundance and LACV seroprevalence were greatest on the SW. In sync with Ae. triseriatus abundance but in contrast to the chipmunk results, mosquito LACV detection was significantly greater on unlogged sites. Surprisingly, LACV was detected in Ae. japonicus and Cx. pipiens/restuans. In a follow-up study, I isolated LACV from field-collected Ae. japonicus. Although LACV was previously isolated from Cx. pipiens, the vector competence was unknown. Therefore, I examined the vector competence of Cx. pipiens and Cx. restuans. Although poor vectors, I did detect LACV in the saliva of both species. An additional experiment found that nutritionally-stressed Cx. restuans were better vectors than those in the control group, indicating that environmental stressors (e.g., FCD) may alter the ability of accessory vectors to spread LACV. The influence of FCD on LACV is complex. Because logging decreases Ae. triseriatus abundance, human LACV risk is likely lowered by decreased transovarial vertical transmission. However, high chipmunk seroprevalence on disturbed sites suggest horizontal transmission with accessory vectors plays a larger role in LACV risk on recently logged sites.en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:3386en
dc.identifier.urihttp://hdl.handle.net/10919/64932en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectforest disturbanceen
dc.subjectmosquito communityen
dc.subjectarbovirus vectorsen
dc.subjectchipmunksen
dc.subjectAedes japonicusen
dc.subjectCulexen
dc.subjectAedes triseriatusen
dc.subjectLa Crosse encephalitis virusen
dc.subjectTamias striatusen
dc.titleForest disturbance, mosquito vector ecology and La Crosse virus dynamics in southwestern Virginiaen
dc.typeDissertationen
thesis.degree.disciplineBiological Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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