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Joana Dark, eight months pregnant, sits with her husband in their community in Recife, Pernambuco state, Brazil. Residents said several members of the community were currently sick with mosquito-borne illnesses including the Zika virus. Photograph by Mario Tama, Getty

To Prevent Zika Birth Defects, CDC Suggests Abstinence

The U.S. Centers for Disease Control and Prevention has responded to the discovery that Zika virus can be transmitted sexually, recommending that if pregnant women’s partners have traveled to areas where the virus is circulating, they either rigorously use condoms, or abstain from sex til the pregnancy has ended.

It is one of several pieces of news that are complicating the debate over how best to protect against Zika infection, which is exploding in South and Central America and is linked to an apparent epidemic of birth defects in Brazil. On Wednesday, the European Centre for Disease Prevention and Control said it had been notified of Zika being passed via blood transfusion. Also on Friday, the United Nations chief of human rights, and subsequently the secretary general, said that countries which restrict access to birth control and abortion—which includes many of the 31 countries where the disease is burgeoning—must repeal those laws in response to Zika. And Brazilian health authorities said they have detected virus in the saliva and urine of infected people, though they could not draw conclusions about whether it is transmitted by those body fluids.

The CDC’s recommendations are a response to the announcement Tuesday by Dallas County Health and Human Services Department that a man in Dallas transmitted the virus to his sexual partner after returning from traveling in Venezuela. (The department did not specify the gender of the man’s partner and said a pregnancy was not involved.) They also come after a woman in Hawaii, who was infected while living in South America in the early stages of pregnancy, gave birth to a baby with the Zika-related birth defect microcephaly. The CDC has recommended that pregnant women not travel to 30 countries and jurisdictions where the virus is circulating, in the Caribbean, Central and South America, and the Pacific Islands, as well as the US territory of Puerto Rico.

In a conference call with reporters Friday, CDC director Dr. Thomas Frieden cautioned that it has been 70 years since an infectious disease has posed a direct threat to fetuses—rubella, in that case. (See “Way Before Zika, Rubella Changed Minds on Abortion” at National Geographic News.)

“We are not aware of any prior mosquito-borne disease associated with such a potentially devastating birth outcome on a  scale anything like what appears to be occurring with Zika,” he said. “Because this phenomenon is so new we are quite literally discovering more about it each and every day.”

The CDC’s new recommendations say:

  • Men who live in or have traveled to places where Zika virus is being transmitted, and whose partner is pregnant, should either abstain from sex as long as the pregnancy lasts, or should use condoms for vaginal, anal or oral sex.
  • Men who live in or travel to places where Zika is being transmitted, and have a sexual partner who is not currently pregnant, may want to consider either using condoms or abstaining from sex.

The CDC earlier recommended that pregnant women who live in areas where Zika is circulating should strictly avoid mosquito bites.

In an odd coincidence, the recommendations come four days after the CDC separately published recommendations for women about alcohol use and possible pregnancy, which were widely criticized for not addressing the role of men.

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Countries where Zika is spreading as of Feb. 4 2016 (excludes cases in the United States). Graphic by the European Centre for Disease Control and Prevention; original here.

Asked about sexual transmission to women who are not pregnant or to same-sex partners, Frieden pointed out that Zika is most often a mild illness in adults, though it has been linked to the paralytic syndrome Guillain-Barre. “Our primary concern and priority here is the protection of pregnant women,” he said.

In a separate set of recommendations, the CDC updated its advice for pregnant women who may have been exposed to Zika, suggesting that women who have traveled where it is circulating be tested for the virus (from 2 to 12 weeks after returning to the United States) even if they do not show symptoms. The agency cautioned though that the tests can return false results because they cross-react to infection with other mosquito-borne viruses, and Frieden said the tests may be in short supply for a while. “We wish more tests were available; our laboratories are literally working around the clock to get tests kits out,” he said. “Not everyone who wants a test will be able to get it.”

The CDC has made Zika a reportable disease in the United States, meaning that state health authorities should report new diagnoses to the agency. So far, Frieden said, the CDC has been told of 51 cases in the United States, 50 imported and the single sexually associated case, and 21 in Puerto Rico. Of those 72 cases, seven are pregnant women, he said. (The CDC maintains a map, not yet updated with those numbers.)

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