Last November, a couple from Washington, D.C., took a weeklong vacation. They visited Mexico, Guatemala and Belize. And got bitten by plenty of mosquitoes.
Two days after they returned home, the woman — who was pregnant — fell ill. She had muscle pain, a fever and a rash.
"At first she didn't think much about it," says OB-GYN Rita Driggers, who saw the woman at Johns Hopkins University School of Medicine. "But then all the news started coming out about Zika, so the woman went and got tested."
The test came back positive. And then the big question became: Was her baby going to be OK?
At first, everything looked good on a standard ultrasound, Driggers says. Even during the 20th week of the pregnancy, the fetus didn't have microcephaly or calcifications in the brain — two telltale signs of a Zika infection.
But when doctors looked more closely at the ultrasound and ran MRI on the fetus, the good news quickly faded.
"There were severe abnormalities within the brain," Driggers says. "The width of the brain was very, very thin. ... Some structures were completely missing."
The woman decided to terminate the pregnancy. And she allowed Driggers and her colleagues to study the baby. The case — published Wednesday in The New England Journal of Medicine — offers insights into how Zika infects a fetus and suggests ways women may be able to find out earlier whether babies will have birth defects.
First, the virus lingered in the patient's blood for months after she got sick. Usually a person's immune system clears out Zika in a week or so. But in this case, Driggers thinks the virus was hiding out inside the fetus — and repeatedly infecting the mother.
"So if you're seeing the virus in the mom's blood more than a week after symptoms," Driggers says, "then perhaps what's going on is that the baby is infected with Zika."
Second, looking only for microcephaly isn't enough. Right now the Centers for Disease Control and Prevention recommends doctors measure the size of the fetus's head with an ultrasound near the 20th week of the pregnancy to check for Zika-related problems.
But with this new case, doctors could see brain abnormalities by ultrasound and MRI before there were signs of microcephaly.
"This is very alarming," says Dr. Carla Janzen, a maternal-fetal medicine specialist at UCLA, who wasn't involved in the study. "If we see more cases like this, the [CDC's] guidelines will probably have to change."
STEVE INSKEEP, HOST:
Some other news now - scientists are reporting a new way to detect brain damage in fetuses infected with the Zika virus. Women often have to wait months and months to find out if their babies will have birth defects. As NPR's Michaeleen Doucleff reports, a new study shows how some women may be able to find out sooner.
MICHAELEEN DOUCLEFF, BYLINE: The case involves a 33-year-old pregnant woman. She was on vacation in Guatemala, and when she returned home to Washington, D.C., she got sick. Doctors confirmed it was Zika and sent her for an ultrasound. That's the standard test doctors use to diagnose microcephaly, a condition where babies are born with extremely small heads. It's been associated with Zika. The fetus looked normal, but her doctors decided to send her for a whole battery of tests including an MRI of the fetus's brain. The good news quickly vanished.
RITA DRIGGERS: There were severe anomalies within the head that the brain was much smaller than it should have been. And there were system structures that appeared to be absent within the brain as well.
DOUCLEFF: That's Dr. Rita Driggers at Johns Hopkins University. She says extra testing like MRIs give a more complete picture of the fetus's brain. It may help doctors diagnose problems earlier in a pregnancy. The thing is, though, this won't help women in parts of Latin America where advanced tests aren't available. But Driggers and her team found something else that might. The virus lingered in the patient's blood for months after she got sick. In most people, it disappears in a week.
DRIGGERS: So what our case is suggesting is that if you're seeing the virus in the mom's blood for a longer period than the first week after symptoms, that perhaps what's going on is that the baby is actually infected.
DOUCLEFF: It could be more likely to develop brain damage. Driggers and her team published the study in the New England Journal of Medicine. Dr. Carla Janzen studies fetal maternal medicine at UCLA. She says the findings could lead to changes in the official guidelines for testing pregnant women for Zika if they're confirmed in more cases.
CARLA JANZEN: Guidelines should never be based on one case, but this is a completely new finding that would maybe shatter what we know so far.
DOUCLEFF: And with the Zika virus, we know so little right now, Janzen says, every bit of new information is precious. Michaeleen Doucleff, NPR News. Transcript provided by NPR, Copyright NPR.