RECIFE, BRAZIL - FEBRUARY 01:  João Heitor baby born with microcephaly is held by his mother Gabrielly Santana da Paz  as they wait to see a doctor at Oswaldo Cruz Hospital on February 1, 2016 in Recife, Brazil.  Health officials believe as many as 100,000 people have been exposed to the Zika virus in Recife, although most never develop symptoms. In the last four months, authorities have recorded around 4,000 cases in Brazil in which the mosquito-borne Zika virus may have led to microcephaly in infants. The ailment results in an abnormally small head in newborns and is associated with various disorders including decreased brain development. According to the World Health Organization (WHO), the Zika virus outbreak is likely to spread throughout nearly all the Americas. (Photo by Diego Herculano/Brazil Photo Press/LatinContent/Getty Images)