El Salvador’s health ministry has advised couples to avoid conceiving children over the next two years. This remarkable cautionary advice, on 21 January, followed similar recommendations, albeit for shorter timespans, by the health ministries in Colombia and Ecuador. The reason is the rapid spread through Latin America of the Zika virus and its suspected link to congenital microcephaly in which the foetal brain fails to develop normally. The Pan American Health Organization (PAHO), the regional office of the World Health Organization (WHO), issued a warning this week that Zika would “likely reach all countries and territories of the region where Aedes [Aegypti] mosquitoes are found”. With the mosquito- borne virus Chikungunya emerging in 2014 to join dengue in the region the public will be asking “what next?”