Doctors should ask all pregnant women in the United States whether they may have been exposed to the Zika virus—the mosquito-borne illness that’s been linked to birth defects in recent months—according to new CDC guidelines announced this week. Moms-to-be should also be offered a blood test if they think they may have been infected, whether they’ve experienced symptoms or not.
Under the new recommendations, women can opt for a Zika-specific blood test for up to 14 days after potential exposure. This test was previously only recommended for a seven-day window, but scientists have since found evidence that the virus can stay in a pregnant woman’s blood for longer than originally thought.
If it’s been more than two weeks since a woman may have been infected, the guidelines state, she should be offered a non-specific blood test that can suggest (but not prove) that she’s had a virus like Zika. Women who test positive can then be given the Zika-specific test, which may (or may not) be able to provide conclusive results.
“Not everyone will see a health care provider while they are sick with Zika and many will not have symptoms,” stated a CDC press release about the new guidelines. Expanding the use of blood testing could help more women get definitive diagnoses, it says, “and help direct medical evaluation and care.”
The CDC also updated its definition of “sexual exposure” to the Zika virus—in light of the first reports of a female-to-male transmission—to include sex with any person, man or woman, who has traveled to or lives in an area with Zika.
Researchers still believe that it’s uncommon to get Zika from sex with an infected women, and that men who have sex with women aren’t at risk for serious side effects anyway. But pregnant women who have female sex partners should be aware, they say, that transmission is possible. (Sex, by the way, includes all kinds, like oral, and maybe even the sharing of sex toys.)
There have still been no confirmed Zika infections from mosquito bites acquired in the United States, although health officials are investigating two possible cases in Florida. Several women have become infected, however, after having sex with male partners who have spent time in countries where the virus is prevalent.
The CDC continues to recommend that women who are pregnant or are trying to get pregnant avoid traveling to these countries, and abstain from sex—or use protection—with anyone who has. They should also take steps to prevent mosquito bites, like wearing EPA-registered insect repellants when spending time outdoors, no matter where they are.