Ongoing outbreak of West Nile virus infection in humans, Greece, July to August 2011

Between 16 July and 21 August 2011, 31 cases of West Nile neuroinvasive disease were reported from four regions in Greece. Of these, 17 occurred in districts that had not been affected in 2010. The reoccurrence of human cases in two consecutive years (following the large 2010 outbreak) and the spread of the virus in new areas suggest that West Nile virus is established in Greece, and its transmission may continue to occur in the future.