Luana Vieira, 4 months old, and born with microcephaly, sleeps in a beach chair as her mother Rosana...
Luana Vieira, 4 months old, and born with microcephaly, sleeps in a beach chair as her mother Rosana Viera Alves (R rear) stands in the sea with her other daughter Laiane Sophia in Olinda, Brazil, February 4, 2016. The suspected link between the Zika virus and a birth defect known as microcephaly appears "stronger and stronger" as researchers study whether there is a causal connection, the head of the U.S. Centers for Disease Control and Prevention said on Friday. Picture taken February 4, 2016. REUTERS/Ueslei Marcelino