US-Brazil teams probe link between Zika and microcephaly

Joint teams of U.S. and Brazilian health workers will fan out across one of Brazil's poorest states Feb. 23 in search of mothers and infants for a study aimed at determining whether the Zika virus is causing babies to be born with unusually small heads.

Brazil's health minister, Marcelo Castro, says he is "absolutely sure" mosquito-borne Zika is responsible for a spike in cases of the rare birth defect microcephaly, which sees babies born with small heads and brains and can cause severe developmental problems. But with scant scientific literature published on the matter, some doctors in Brazil and elsewhere say there is not yet enough scientific data to prove the connection.

Jointly run by the Brazil's Health Ministry and the U.S. Centers for Disease Control and Prevention, the study is intended to fill that vacuum by comparing babies with microcephaly and their mothers to babies without the condition.

The popular "understanding is that Zika virus [behind the microcephaly spike]. How much of that is Zika virus is really one of the important goals of this study," said Erin Staples, a Colorado-based epidemiologist who heads the CDC contingent in Paraiba state. "I do believe there is something occurring that is unique and knowable, but we really need to understand better, mostly so we can prevent this from happening to other generations."

Eight teams made up of one CDC staffer and three Brazilian health workers will knock on the doors of several hundred randomly selected families with infants throughout Paraiba, a northeastern coastal state that is one of Brazil's least developed. The teams hope to recruit at least 130 babies with microcephaly and their mothers and two to three times that number of mothers and babies without the...