The spread of Zika is the price being paid for a massive policy failure on mosquito control, says World Health Organization leader Margaret Chan. Speaking at the agency's annual World Health Assembly, Dr Chan said experts had "dropped the ball" in the 1970s with regards to getting a handle on disease-carrying insects. More than 60 countries and territories now have continuing Zika transmission. Most recently, the infection, spread by mosquito bites, reached Africa. ... Eradication campaigns were successful in the Americas with 18 countries getting rid of the insect by 1962. But insecticide resistance plus a lack of political will...