Influenza is known to be a quite frequent infection among travellers to tropical and subtropical destinations compared to other infections, e.g. vector-borne ones. About one of hundred travellers abroad gets infected [7] . The risk of infection depends on the travel destination and the season. Travellers crossing hemispheres may be confronted with different antigenic variants of the influenza virus. By returning home, the new variant may be transmitted to contact persons [11] . The first pandemic of the 21st century has highlighted the need for international influenza prevention strategies [12] .