title: A novel epidemiological model to better understand and predict the observed seasonal spread of Pestivirus in Pyrenean chamois populations.
abstract: Seasonal variations in individual contacts give rise to a complex interplay between host demography and pathogen transmission. This is particularly true for wild populations, which highly depend on their natural habitat. These seasonal cycles induce variations in pathogen transmission. The seasonality of these biological processes should therefore be considered to better represent and predict pathogen spread. In this study, we sought to better understand how the seasonality of both the demography and social contacts of a mountain ungulate population impacts the spread of a pestivirus within, and the dynamics of, this population. We propose a mathematical model to represent this complex biological system. The pestivirus can be transmitted both horizontally through direct contact and vertically in utero. Vertical transmission leads to abortion or to the birth of persistently infected animals with a short life expectancy. Horizontal transmission involves a complex dynamics because of seasonal variations in contact among sexes and age classes. We performed a sensitivity analysis that identified transmission rates and disease-related mortality as key parameters. We then used data from a long-term demographic and epidemiological survey of the studied population to estimate these mostly unknown epidemiological parameters. Our model adequately represents the system dynamics, observations and model predictions showing similar seasonal patterns. We show that the virus has a significant impact on population dynamics, and that persistently infected animals play a major role in the epidemic dynamics. Modeling the seasonal dynamics allowed us to obtain realistic prediction and to identify key parameters of transmission.
authors.affiliation: INRA, Oniris, LUNAM Université, UMR1300 BioEpAR, CS40706, F-44307 Nantes, France. gael.beaunee@gmail.com.
authors.forename: Gaël
authors.initials: G
authors.lastname: Beaunée
authors.affiliation: Université de Lyon, VetAgro Sup-Campus Vétérinaire de Lyon, Marcy l'Etoile, France. emmanuelle.gilotfromont@vetagro-sup.fr.|Université de Lyon, Université Lyon 1, UMR CNRS 5558 Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France. emmanuelle.gilotfromont@vetagro-sup.fr.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Gilot-Fromont
authors.affiliation: Office National de la Chasse et de la Faune Sauvage, Centre National d'Études et de Recherche Appliquée Faune de Montagne, Gières, France. mathieu.garel@oncfs.gouv.fr.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Garel
authors.affiliation: INRA, Oniris, LUNAM Université, UMR1300 BioEpAR, CS40706, F-44307 Nantes, France. pauline.ezanno@oniris-nantes.fr.
authors.forename: Pauline
authors.initials: P
authors.lastname: Ezanno
mesh_terms: D000818:Animals; D001882:Border Disease / Q000453:epidemiology / Q000635:transmission*; D018083:Border disease virus / Q000502:physiology*; D003710:Demography; D005260:Female; D005602:France / Q000453:epidemiology; D008297:Male; D008954:Models, Biological; D011157:Population Dynamics; D015995:Prevalence; D048608:Rupicapra / Q000502:physiology; D016036:Seroepidemiologic Studies; D012919:Social Behavior