The World Health Organization said Tuesday that it expects Brazil will have more than 2,500 babies born with a severe birth defect known as microcephaly if current trends continue in the Zika virus outbreak.
Data from Brazil, the epicenter of an epidemic that has hit more than three dozen countries and territories in the Americas, show that about 39 percent of 2,212 investigated cases of microcephaly are already confirmed for the rare congenital condition. To date, that's 863 babies born with the characteristic abnormally small heads and underdeveloped brains, WHO detailed at a news conference in Geneva.
"If that rate continues, we expect more than 2,500 cases will emerge of babies with brain damange and clinical signs of microcephaly," said Anthony Costello, who heads WHO's department of maternal, newborn, child and adolescent health.
WHO Director-General Margaret Chan said new evidence is becoming clear daily about the mosquito-borne virus. But a pattern seems to be emerging: Initial detection of Zika is followed within about three weeks by an unusual increase of Guillain-Barre syndrome, a rare condition that can cause paralysis and sometimes death. Detection of microcephaly and other fetal abnormalities come later as pregnancies of infected women come to term, she said.
Brazil and Panama are now reporting cases of microcephaly -- including 6,480 suspected cases in Brazil. Columbia is investigating many cases for a possible link. A WHO team is currently in Cape Verde to investigate that country's first reported case of microcephaly, Chan said.
A total of 12 countries and territories have now seen an increase in the incidence of Guillain-Barre or actual lab confirmation of Zika among cases with the syndrome, she said.
Although Zika has hit countries in Latin America and the Caribbean the hardest, Chan warned that no one can predict if it will spread to other parts of the world and trigger the same pattern of health complications.
"If this pattern is confirmed beyond Latin America and the Caribbean, the world will face a severe public health crisis," she said.
The Cape Verde archipelago off West Africa has more than than 7,000 Zika infections, including its first case last week of a newborn with microcephaly. The baby was born at 30 weeks gestation and died shortly after birth, Chan said.