International Journal of Infectious Diseases 32 (2015) 170–178 http://dx.doi.org/10.1016/j.ijid.2014.11.023 1201-9712/ß 2014 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).