Since I wrote about Zika in February, genome sequencing has shown that the virus has three lineages: West African, East African and Asian. Analysis of a 1966 Malaysian strain and a 1968 Nigerian one point to an Asian origin for the Brazilian viruses; it is likely that Zika has been circulating in Brazil since 2013. The virus has been evolving in expected ways (its RNA genome has a high mutation rate); no change that could account for an enhanced ability to damage the brain has yet been found. None of these findings has hit the headlines.