title: Use of mapping and statistical modelling for the prediction of bluetongue occurrence in Switzerland based on vector biology.
abstract: Due to the spread of bluetongue (BT) in Europe in the last decade, a sentinel surveillance programme was initiated for Switzerland in 2003, consisting of serological sampling of sentinel cattle tested for BT virus antibodies, as well as entomological trapping of Culicoides midges from June until October. The aim of this study was to create a 'suitability map' of Switzerland, indicating areas of potential disease occurrence based on the biological parameters of Obsoletus Complex habitat. Data on Culicoides catches from insect traps together with various environmental parameters were recorded and analysed. A multiple regression analysis was performed to determine correlation between the environmental conditions and vector abundance. Meteorological data were collected from 50 geo-referenced weather stations across Switzerland and maps of temperature, precipitation and altitude were created. A range of values of temperature, precipitation and altitude influencing vector biology were obtained from the literature. The final combined map highlighted areas in Switzerland which are most suitable for vector presence, hence implying a higher probability of disease occurrence given the presence of susceptible animals. The results confirmed the need for an early warning system for the surveillance of BT disease and its vectors in Switzerland.
authors.affiliation: Federal Veterinary Office, Schwarzenburgstrasse 155, 3003 Bern, Switzerland. vanessa.racloz@bvet.admin.ch
authors.forename: Vanessa
authors.initials: V
authors.lastname: Racloz
authors.forename: Patrick
authors.initials: P
authors.lastname: Presi
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
authors.forename: Heinzpeter
authors.initials: H
authors.lastname: Schwermer
authors.forename: Simona
authors.initials: S
authors.lastname: Casati
authors.forename: Tullio
authors.initials: T
authors.lastname: Vanzetti
authors.forename: Christian
authors.initials: C
authors.lastname: Griot
authors.forename: Katarina D C
authors.initials: KD
authors.lastname: Stärk