RECIFE, BRAZIL - FEBRUARY 01: David Henrique Ferreira, 5 months, who was born with microcephaly, is held by his mother Mylene Helena Ferreira as they wait to see a doctor on February 1, 2016 in Recife, Pernambuco state, Brazil. Ferreira says she spends up to eight hours per day in transit on buses, three days per week, to visit a litany of doctors with David. In the last four months, authorities have recorded thousands of 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. The World Health Organization (WHO) declared the Zika virus a "public health emergency of international concern" today. (Photo by Mario Tama/Getty Images)
