Zika virus country classification scheme
The geographical distribution of Zika virus (ZIKV) has expanded globally, particularly since 2015 in the Americas. Since 2013, 31 countries and territories have reported cases of microcephaly and other central nervous system malformations associated with ZIKV infection, as of 17 February 2017. There are significant knowledge gaps around ZIKV and a lack of historical data on its vectors, transmission dynamics, and geographical distribution. Despite these challenges, there is a need to better describe the epidemiology of ZIKV transmission in a given place, at a given time in order to allow an assessment of the possibility of ZIKV infection for various populations, and to adapt public health recommendations accordingly for residents and travellers.
The proposed definitions in this interim guidance refine and replace those presented in the WHO interim guidance on surveillance for ZIKV infection, microcephaly and Guillain-Barré syndrome (7 April 2016).