In late 2015, Brazil reported a 20-fold increase in babies born with microcephaly, an abnormal smallness of the head, usually accompanied by an underdeveloped brain, which was thought to be linked to an epidemic of the Zika virus.
With the approach of the Olympic and Paralympic Games in Rio de Janeiro, the news was reported around the globe and the World Health Organization announced a ‘public health emergency of international concern’ in February 2016. A race to fast-track research and share data ensued; 62 countries have now reported Zika cases.
Zika was first identified in 1947, in the Zika forest of Uganda, before spreading eastward to South East Asia and the Pacific, and from there on to Brazil. Studies have provided evidence for a causal link between Zika infection in the first trimester of pregnancy and congenital defects, including microcephaly.