Zika virus is a fl avivirus that was fi rst isolated in 1947 from a sentinal rhesus monkey in a Ugandan forest, with the fi rst human cases identifi ed 5 years later in Nigeria. Humans become infected with Zika virus mainly through the bites of several species of aedes mosquitoes, including Aedes aegypti and presumably Aedes albopictus.3 Eradication of Zika virus poses substantial challenges because of its sylvatic transmission cycle between aedes mosquitoes and non-human
primates. Although Zika virus is known to have circulated in parts of Africa and the Asia-Pacifi c region, a series of epidemics during the past decade have transported this virus eastward across islands in the Pacifi c Ocean. On May 15, 2015, the Program for Monitoring Emerging Diseases (ProMED-mail) published a report confi rming locally acquired cases of Zika virus in several northeastern Brazilian states, marking the fi rst time that the virus is known to have spread within the Americas.On Feb 1, 2016, WHO declared this epidemic to be a global Public Health Emergency of International Concern, mainly because of its rapid spread between countries and its vertical transmission of human infection resulting in birth defects, including but not limited to microcephaly and an association with Guillain-Barré syndrome. As of June 27, 2016, autochthonous transmission of Zika virus has been confi rmed in 40 countries and territories within the Americas. As the epidemic expands its range, increasing numbers of travellers are transporting Zika virus to distant regionsacross the world. If competent mosquito vectors become infected from these travellers in areas where environmental conditions are conducive to the virus’s spread, new epidemics could occur, subject to the presence of an immunologically susceptible human population. During warmer months across the northern hemisphere when mosquito vectors are most abundant, active, and capable of transmitting arboviruses to humans, the risk of new epidemics appearing outside of the Americas is expected to peak. To support public health readiness, we aim to identify regions and times where the potential