title: Early detection of West Nile virus in France: quantitative assessment of syndromic surveillance system using nervous signs in horses.
abstract: West Nile virus (WNV) is a growing public health concern in Europe and there is a need to develop more efficient early detection systems. Nervous signs in horses are considered to be an early indicator of WNV and, using them in a syndromic surveillance system, might be relevant. In our study, we assessed whether or not data collected by the passive French surveillance system for the surveillance of equine diseases can be used routinely for the detection of WNV. We tested several pre-processing methods and detection algorithms based on regression. We evaluated system performances using simulated and authentic data and compared them to those of the surveillance system currently in place. Our results show that the current detection algorithm provided similar performances to those tested using simulated and real data. However, regression models can be easily and better adapted to surveillance objectives. The detection performances obtained were compatible with the early detection of WNV outbreaks in France (i.e. sensitivity 98%, specificity >94%, timeliness 2·5 weeks and around four false alarms per year) but further work is needed to determine the most suitable alarm threshold for WNV surveillance in France using cost-efficiency analysis.
authors.affiliation: INRA UR0346 Animal Epidemiology,VetagroSup, Marcy l'Etoile,France.
authors.forename: C
authors.initials: C
authors.lastname: Faverjon
authors.affiliation: Epi-Connect, Djupdalsvägen Skogås,Sweden.
authors.forename: F
authors.identifier: 0000-0003-3603-4694
authors.initials: F
authors.lastname: Vial
authors.affiliation: Department of Chemistry,Environment and Feed Hygiene. The National Veterinary Institute,Uppsala,Sweden.
authors.forename: M G
authors.initials: MG
authors.lastname: Andersson
authors.affiliation: UPE, ANSES,Animal Health Laboratory,UMR1161 Virologie, INRA, ANSES, ENVA,Maisons-Alfort,France.
authors.forename: S
authors.initials: S
authors.lastname: Lecollinet
authors.affiliation: Réseau d'EpidémioSurveillance en Pathologie Equine (RESPE),Caen,France.
authors.forename: A
authors.initials: A
authors.lastname: Leblond
mesh_terms: D000818:Animals; D005602:France / Q000453:epidemiology; D006734:Horse Diseases / Q000209:etiology* / Q000473:pathology*; D006736:Horses; D009422:Nervous System Diseases / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D012680:Sensitivity and Specificity; D018571:Sentinel Surveillance; D014901:West Nile Fever / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D014902:West Nile virus / Q000302:isolation & purification*
keywords: Early detection; West Nile virus; horses; nervous signs; syndromic surveillance