CDC ships Zika virus test for pregnant women

WASHINGTON — The government is shipping Zika virus tests for pregnant women to health departments around the country, but warning there could be temporary shortages, as travelers try to tell if they returned with an infection that could put a developing baby at risk.

Health officials don’t expect widespread transmission of the mosquito-borne virus in the continental United States, but said Thursday that Puerto Rico is especially vulnerable. They asked for emergency funding from Congress to battle an outbreak that is quickly spreading through Latin America.

“We may see rapid spread through the island and we need to respond urgently,” Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, told a Senate appropriations subcommittee.

The Zika virus is suspected of causing a rare but potentially devastating birth defect, an abnormally small head, which can indicate underlying brain damage. Brazil has reported an apparent increase in cases of that defect, called microcephaly, as Zika exploded in that country, although scientists haven’t definitively proven the link.

“With each passing day the evidence that Zika is causally related gets stronger,” Frieden said. “Even in this week, the data that’s come out makes it look very much like this is a virus that’s what we call neurotropic — it targets the nerve cells.”

His agency last month found the Zika virus in the brain tissue of two dead newborns from Brazil and in placentas from two miscarriages. On Wednesday, European researchers caring for a woman who returned there from Brazil reported a post- abortion autopsy that found the virus in her fetus’ severely damaged brain — one a fraction of the proper size and lacking the usual crinkly folds.

If someone is actively infected, the CDC has a test that diagnoses Zika fairly well. But most people experience no symptoms or a very mild one, and the antibody test used to tell afterward if they were infected isn’t very accurate.