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dc.contributor.authorHahn, Ninaen_US
dc.date.accessioned2014-03-14T21:19:03Z
dc.date.available2014-03-14T21:19:03Z
dc.date.issued1990-05-05en_US
dc.identifier.otheretd-09202005-090950en_US
dc.identifier.urihttp://hdl.handle.net/10919/39407
dc.description.abstractThree studies relating to the vector competency of several species of ticks and Simulium spp. (blackflies) for Ehrlichia risticii, causative agent of Potomac horse fever (PHF) and Amblyomma variegatum for Cowdria ruminantium, causative agent of heartwater, are described. Dermacentor variabilis, Rhipicephalus sanguineus, Amblyomma americanum and Ixodes scapularis ticks were investigated for their ability to acquire and transmit PHF. Larval and nymphal ticks were exposed to E. risticii by feeding on mice inoculated with the organism. Molted exposed ticks were then allowed to feed on susceptible ponies or mice and were examined by light and electron microscopy. No evidence of transmission, either clinically or by seroconversion in mice or ponies was observed. Blackflies (Simulium spp.) were trapped in an area endemic for PHF and inoculated into mice in an attempt to demonstrate I. risticii. No evidence of seroconversion by mice to E. risticii was observed. Two laboratory colonies of Amblyomma variegatum ticks were investigated for their ability to acquire and transmit C. ruminantium and was febrile. Nymphs from both laboratory groups were simultaneously fed on a goat that had been infected with C. ruminantium and was febrile. Engorged nymphs from both groups were replete from feeding on three consecutive days. Nymphs from both groups were then incubated under identical conditions until molting.en_US
dc.format.mediumBTDen_US
dc.publisherVirginia Techen_US
dc.relation.haspartLD5655.V856_1990.H335.pdfen_US
dc.subjectTick-borne diseasesen_US
dc.subjectVector-pathogen relationshipsen_US
dc.subject.lccLD5655.V856 1990.H335en_US
dc.titleInvestigations into the vector competency of arthropods for two Ehrlichias: Ehrlichia risticii and Cowdria rumantiumen_US
dc.typeDissertationen_US
dc.contributor.departmentVeterinary Medical Sciencesen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineVeterinary Medical Sciencesen_US
dc.contributor.committeechairZajac, Anne M.en_US
dc.contributor.committeememberSchurig, Gerhardt G.en_US
dc.contributor.committeememberPerry, Brian D.en_US
dc.contributor.committeememberSonenshine, Danielen_US
dc.contributor.committeememberKocan, Katherine M.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-09202005-090950/en_US
dc.date.sdate2005-09-20en_US
dc.date.rdate2005-09-20
dc.date.adate2005-09-20en_US


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