In this Dec. 23, 2015, file photo, 10-year-old Elison nurses his 2-month-old brother Jose Wesley, who was born with microcephaly, at their house in Poco Fundo, Pernambuco state, Brazil. The U.S. Centers for Disease Control and Prevention said Wednesday, Jan. 13, 2016, that it has found the strongest evidence so far of a possible link between a mosquito-borne virus and a surge of birth defects in Brazil.