Fig. 4
From: Mapping the cryptic spread of the 2015–2016 global Zika virus epidemic
Susceptible spatial units with a high chance of cryptic ZIKV spread during 2015–2016 (shown in red). If evidence of historical ZIKV circulation prior to 2015 was found in any of these locations, the corresponding polygon is striped. Susceptible spatial units coloured in dark red refer to those that continue to have high potential for cryptic ZIKV spread during 2015–2016 under the highly conservative scenario (i.e. thermal restriction for ZIKV transmission being 26–29 °C)