AUDIE CORNISH, HOST:
Medical detectives from the Centers for Disease Control and Prevention are now in Brazil. They're trying to determine whether the Zika virus is the cause of the startling increase in the number of babies born with deformed heads. NPR health correspondent Rob Stein is with the team. He joins us now from the Northeast of Brazil about 1,500 miles north of Rio de Janeiro. And Rob, the CDC is going to an area where Brazilian experts have been studying this for months. What do they think that they can achieve that we don't know from other investigations?
ROB STEIN, BYLINE: So experts think that the Zika virus is causing this condition microcephaly. You know, it's when babies are born with these abnormally small heads and really badly damaged brains. But the truth is we really still don't know for sure that Zika is the culprit. The evidence is pretty circumstantial so far, and it could turn out that it's something else. So the hope is that this study will try to get some clarity about what's really going on.
CORNISH: How will they try to figure that out?
STEIN: They're launching what's called a case control study. And basically what that means is they're going to try to find more than 100 women who had babies that look like they got microcephaly because of Zika infection when the moms were pregnant and then find a few hundred other moms who are very similar but had healthy babies about the same time. And then they're going to compare them in every possible way they can think of to see if it's really Zika that's to blame or whether it is something else.
CORNISH: All right. And we mentioned you're with that team. What's the day been like so far?
STEIN: So it's been a pretty intense day. Today was the first day of really hard-core training when the Americans got together with their Brazilian counterparts and walked through what they're going to be doing on this study and how they're going to be forming these eight teams to go out and look for these moms who had babies with microcephaly. And they're really getting a crash course on both Zika and on microcephaly. Here's the CDC's Cynthia Moore talking to the group.
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CYNTHIA MOORE: This is a serious health problem, and I think we're all here for the babies and the families and hoping we can find some answers.
STEIN: Now, remember; before all this started, hardly anyone knew anything about Zika, the Zika virus, and microcephaly is such a rare condition that a lot of people didn't really know much about that either. And so today, they're running through all the details about what the Zika virus is, what microcephaly is, how you define it, and they're also going to be running through a very detailed script about what to say to the women that they're interviewing and what questions to ask them, you know - somewhat very personal questions that are very sensitive.
And then tomorrow, these teams are going to fan out in the region, and they're going to start trying to track down these moms with the deformed babies and the moms with the healthy babies. They're going to examine the mothers. They're going to examine the babies. They're going to take blood samples and do blood tests and ask tons and tons of questions to try to figure out if it's really Zika or something else that's really causing microcephaly.
CORNISH: Is there any way to know how soon we'll actually have any answers, Rob, or whether this will actually settle the question of any potential connection?
STEIN: So the CDC thinks and it hopes that it'll take several weeks maybe a month to collect all the data they need to track down all these women and then maybe another month to analyze the data. So they're hoping they'll get some answers by the spring. And now, this isn't the gold standard for scientific evidence that they're going to be getting, but they hope it will be at least the best evidence that we've gotten so far to tell the world really how much of a threat Zika is.
CORNISH: That's NPR's Rob Stein reporting from the Northeast of Brazil. Rob, thank you.
STEIN: Oh, sure. Thank you. Transcript provided by NPR, Copyright NPR.