AdvertisementWHO Warns Of Zika Virus's 'Alarming' And 'Explosive' SpreadJanuary 28, 2016Jason BeaubienfacebookEmailDr. Margaret Chan is director-general of the World Health Organization. In her first major address on Zika, delivered Thursday in Geneva, she said: "Questions abound. We need to get some answers quickly." (/epa/Corbis)