J. infect. dis. J. infect. dis. Participatory syndromic surveillance of influenza in Europe Guerrisi Caroline Turbelin Clément Blanchon Thierry Hanslik Thomas Bonmarin Isabelle Levy-Bruhl Daniel Perrotta Daniela Paolotti Daniela Smallenburg Ronald Koppeschaar Carl Franco Ana O. Mexia Ricardo Edmunds W. John Sile Bersabeh Pebody Richard van Straten Edward Meloni Sandro Moreno Yamir Universidad de Zaragoza Duggan Jim Kjelsø Charlotte Colizza Vittoria 2016 research-article