These papers are posted in the context of the Public Health Emergency of International Concern declared by the Director-General of the World Health Organization 1 February 2016. The data in these papers are freely available for unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited as indicated by the Creative Commons Attribution 3.0 Intergovernmental Organizations license (CC BY IGO 3.0). go to the website: http://www.who.int/bulletin/online_first/zika_open/en/