The epidemic West Nile virus strain in Greece was a recent introduction

Abstract

To estimate the prevalence of West Nile virus (WNV) immunoglobulin G (IgG) antibodies in residents of northern Greece before the large outbreak of 2010, stored serum samples collected during 2003-2004 from 626 apparently healthy residents of northern Greece were tested. A seroprevalence of 0.62% was detected, with no statistically significant differences among the various prefectures, gender, and age groups, suggesting that the lineage 2 WNV strain that caused the outbreaks for 3 consecutive years was introduced recently. Data from the present study can be used as a threshold in future comparisons with respective data after the outbreaks to estimate and assess the public health impact, as well as for WNV evolutionary studies.