title: Identification of Climatic Factors Affecting the Epidemiology of Human West Nile Virus Infections in Northern Greece.
abstract: Climate can affect the geographic and seasonal patterns of vector-borne disease incidence such as West Nile Virus (WNV) infections. We explore the association between climatic factors and the occurrence of West Nile fever (WNF) or West Nile neuro-invasive disease (WNND) in humans in Northern Greece over the years 2010-2014. Time series over a period of 30 years (1979-2008) of climatic data of air temperature, relative humidity, soil temperature, volumetric soil water content, wind speed, and precipitation representing average climate were obtained utilising the ECMWF's (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA-Interim) system allowing for a homogeneous set of data in time and space. We analysed data of reported human cases of WNF/WNND and Culex mosquitoes in Northern Greece. Quantitative assessment resulted in identifying associations between the above climatic variables and reported human cases of WNF/WNND. A substantial fraction of the cases was linked to the upper percentiles of the distribution of air and soil temperature for the period 1979-2008 and the lower percentiles of relative humidity and soil water content. A statistically relevant relationship between the mean weekly value climatic anomalies of wind speed (negative association), relative humidity (negative association) and air temperature (positive association) over 30 years, and reported human cases of WNF/WNND during the period 2010-2014 could be shown. A negative association between the presence of WNV infected Culex mosquitoes and wind speed could be identified. The statistically significant associations could also be confirmed for the week the WNF/WNND human cases appear and when a time lag of up to three weeks was considered. Similar statistically significant associations were identified with the weekly anomalies of the maximum and minimum values of the above climatic factors. Utilising the ERA-Interim re-analysis methodology it could be shown that besides air temperature, climatic factors such as soil temperature, relative humidity, soil water content and wind speed may affect the epidemiology of WNV.
authors.affiliation: Joint Research Centre, European Commission, Ispra (VA), Italy.|Department of Biometry and Epidemiology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Nikolaos I
authors.initials: NI
authors.lastname: Stilianakis
authors.affiliation: Joint Research Centre, European Commission, Ispra (VA), Italy.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Syrris
authors.affiliation: Joint Research Centre, European Commission, Ispra (VA), Italy.
authors.forename: Thomas
authors.initials: T
authors.lastname: Petroliagkis
authors.affiliation: Joint Research Centre, European Commission, Ispra (VA), Italy.
authors.forename: Peeter
authors.initials: P
authors.lastname: Pärt
authors.affiliation: EcoDevelopment SA, Thessaloniki, Greece.
authors.forename: Sandra
authors.initials: S
authors.lastname: Gewehr
authors.affiliation: EcoDevelopment SA, Thessaloniki, Greece.
authors.forename: Stella
authors.initials: S
authors.lastname: Kalaitzopoulou
authors.affiliation: EcoDevelopment SA, Thessaloniki, Greece.
authors.forename: Spiros
authors.initials: S
authors.lastname: Mourelatos
authors.affiliation: Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens, Greece.
authors.forename: Agoritsa
authors.initials: A
authors.lastname: Baka
authors.affiliation: Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens, Greece.
authors.forename: Danai
authors.initials: D
authors.lastname: Pervanidou
authors.affiliation: Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.
authors.forename: John
authors.initials: J
authors.lastname: Vontas
authors.affiliation: Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Hadjichristodoulou
mesh_terms: D002980:Climate; D005843:Geography; D006115:Greece / Q000453:epidemiology; D006801:Humans; D006813:Humidity; D000072138:Mosquito Vectors; D013696:Temperature; D014901:West Nile Fever / Q000453:epidemiology* / Q000635:transmission