The National Center for Biotechnology Information (NCBI), July 2018
Wilder-Smith A, Chang CR, Leong WY
Travellers contributed substantially to the rapid spread of Zika virus (ZIKV). They act as sentinel and may unmask ongoing ZIKV transmission in countries where outbreaks have not yet been reported. Mobility patterns and travel volumes can help to identify the most likely origin of importation, and also to predict further propagation.