Mother Nature Network: Zika virus was an obscure illness until recently, especially in the Americas. But now it's "spreading explosively" through the New World, the World Health Organization (WHO) warned this week at an emergency meeting about the outbreak.
Zika could infect up to 4 million people before the end of 2016, according to WHO director-general Margaret Chan, who says the virus has gone "from a mild threat to one of alarming proportions." Although Zika has been known to science for seven decades, it's only...