A Stillborn Baby Has Tested Positive for Zika, Raising New Concerns

A stillborn baby born in Brazil with almost no brain tissue has tested positive for Zika virus, stoking new concerns over the potential health risks of the virus.

Zika is already suspected of being linked to microcephaly, a condition where babies are born with abnormally small heads and often have underdeveloped brains. But this new case, detailed in a paper published Thursday in PLOS Neglected Tropical Diseases, shows the virus may also be related to even more severe brain damage.

In January, a 20-year-old pregnant woman in Brazil went in for a routine ultrasound that revealed some troubling news: though she had had a normal, healthy pregnancy until that point, her fetus was now significantly underweight, according to the published report. The woman was referred to a hospital, where a team of doctors began to monitor her. Given the current outbreak, the doctors asked the woman if she had had any symptoms of Zika during her pregnancy (like fever or rash), but she said she hadn't. As her pregnancy progressed, the outlook became more grim: the fetus showed signs of microcephaly as well as hydranencephaly—a near-complete loss of brain tissue—and hydrops fetalis, which is an abnormal accumulation of fluid. At 32 weeks, an ultrasound revealed the fetus was stillborn, and the doctors induced labor.

After the fetus was delivered, the Zika virus was detected throughout its brain and in its spinal and amniotic fluid.

"These findings raise concerns that the virus may cause severe damage to fetuses leading to stillbirths and may be associated with effects other than those seen in the central nervous system," Dr. Albert Ko, chair of the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health and co-author of the study, said in a press release. "Additional work is needed to understand if this is an isolated finding and to confirm whether Zika virus can actually cause hydrops fetalis."

Ko and his colleagues explain in the paper that even though this is only one case, it's alarming in its severity. Microcephaly is a troubling diagnosis, but it's not always a death sentence, and some microcephalic children grow up with full cognitive and physical abilities. But conditions like hydrops fetalis and hydranencephaly are even more severe and deadly.

In the paper, the researchers point out that this patient didn't even know she had Zika—only about one in four people infected are symptomatic—so it could be that this association has already emerged, but we've missed it because we didn't know what to look for. The researchers recommend reviewing cases of stillbirths in Brazil from the last few months to see if this is an isolated incident or a red flag.

Right now, scientists still aren't able to confirm for sure what the link is between Zika and microcephaly, so we're a long way from finding out if the virus can cause stillbirths, and if so, just how high the risk may be. But the case underscores the need to improve vector control—working to eliminate the mosquito that spreads the virus—to stop the spread of the virus as we hurry to understand the dangers it may pose.