CDC: Zika transmittable through anal sex

Apr 14, 2016, 3:51 PM EDT
(Source: Agência Brasília/flickr)
(Source: Agência Brasília/flickr)
The Centers for Disease Control has announced that Zika is possible to transmit through anal sex, describing a man-to-man transmission in January. It was previously thought that Zika was sexually transmittable only through vaginal sex. The New York Times reports:
The case, which was previously disclosed by health officials in Texas without identifying the genders of the partners, was the first known case of sexual transmission of Zika within the United States in the current epidemic.
It involved a Dallas resident who became infected with Zika through a mosquito bite while visiting Venezuela and then infected his male partner through unprotected sex upon his return. Both had relatively mild symptoms, and blood was not detected in either man’s semen.
The big question now is how long the virus can last in the semen of an infected man, and therefore how long he might be capable of infecting someone else through sex. It's also unclear how likely it is that a man infected with Zika will shed it in his semen, and if that only happens with people who show symptoms of the virus. In the six reported cases, all the men with detectable virus in their semen had shown symptoms, but most people who get the Zika virus are asymptomatic.
During a previous outbreak, the virus was detected in the semen of one man two months after his fever had set in. In a more recent case, researchers found the virus in the semen of a French traveler two weeks after he'd been sick (there was a lot more virus in semen than there was in blood or urine, leading them to wonder if the virus can replicate in the male genital tract).
WebMD adds that the CDC has officially declared that Zika causes microcephaly:
Though the virus had been strongly suspected to cause microcephaly and other serious birth defects, scientists had been careful to say that they didn’t yet know whether the appearance of the two things together could be just a coincidence or whether it was a cause-and-effect relationship.
But in a press briefing, experts said there was now enough scientific evidence to prove that Zika causes microcephaly. By clearly laying out that evidence, scientists hope to dispel still-swirling rumors that other agents, such as a chemical that kills mosquito larvae, might be behind the outbreak of microcephaly, which was declared a worldwide public health emergency by the World Health Organization in February.