A log-linear model for predicting risk factors for rabies positivity in raccoons in Virginia, 1984-1987

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dc.contributor.authorTorrence, Mary Elizabethen
dc.contributor.committeechairMoore, Daviden
dc.contributor.committeememberLichtman, Marilyn V.en
dc.contributor.committeememberLee, J.C.en
dc.contributor.committeememberSouthard, Douglas R.en
dc.contributor.committeememberJenkins, Suzanne R.en
dc.contributor.departmentVeterinary Medical Sciencesen
dc.date.accessioned2014-03-14T21:16:51Zen
dc.date.adate2008-07-28en
dc.date.available2014-03-14T21:16:51Zen
dc.date.issued1990en
dc.date.rdate2008-07-28en
dc.date.sdate2008-07-28en
dc.description.abstractIn response to an epidemic of rabies in the mid-Atlantic region, the Virginia Department of Health and the Consolidated Laboratory Services in 1982, redesigned their submission forms for animals being tested for rabies in an effort to elicit detailed information about the epidemiology of rabies in Virginia. The information collected from those submission forms was used in a mathematical model analysis of the epidemiology of raccoon rabies in Virginia for the years 1984 through 1987. Eleven explanatory variables and one response variable (positivity for rabies) were examined. The objective of this study was to develop a model, through logistic regression, that would explain the epidemiology of rabies in raccoons in Virginia, and determine the risk factors for prediction for positivity for rabies in raccoons in Virginia. This information would aid further surveillance efforts, preventive education programs, and in formulating future oral vaccination programs in raccoons. Multiway contingency tables were constructed (involving 2,3,4,5,and 6 way interactions), and log-linear models were fitted using an iterative fitting process to generate maximum likelihood estimates. The goodness of fit of each model was judged using the likelihood-ratio-chi-square p value (0.01). The backward stepwise model selection process was performed on logit models to find the best fitting model (0.01). The final model consisted of a combination of 17 four variable term models. Eight of the eleven explanatory variables remained important risk factors in the prediction of positivity for rabies in raccoons. To validate the model, it was applied to data collected in the years 1988 through July 1989. The model fit at the 0.01 level. Parameter estimates were calculated for each term in the model. All eight variables had main order effects (direct) on the response variable (positivity for rabies). Three second order effects were evident: age and season, behavior and season, and year and season. Future studies will involve applications of this model to other species to further explore the epidemiology of rabies, and to refine the model for practical applications.en
dc.description.degreePh. D.en
dc.format.extentix, 120 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-07282008-135746en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07282008-135746/en
dc.identifier.urihttp://hdl.handle.net/10919/38989en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V856_1990.T677.pdfen
dc.relation.isformatofOCLC# 23174751en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V856 1990.T677en
dc.subject.lcshRabies in animals -- Virginiaen
dc.subject.lcshRabies virus -- Virginiaen
dc.subject.lcshRaccoons as carriers of disease -- Virginiaen
dc.titleA log-linear model for predicting risk factors for rabies positivity in raccoons in Virginia, 1984-1987en
dc.typeDissertationen
dc.type.dcmitypeTexten
thesis.degree.disciplineVeterinary Medical Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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