William King via Getty Images The case of sexually transmitted Zika reported in Dallas in February involved two male partners.

In February, when Dallas health officials reported the first case of sexually transmitted Zika virus in the U.S., they left a key piece of information out of their report: The unnamed Dallas county patient was a man who had contracted Zika virus after unprotected anal sex with his partner, who'd recently visited Venezuela, the U.S. Centers for Disease Control and Prevention reported in its Morbidity and Mortality Weekly Report on Thursday.

While much of the media attention surrounding sexually transmitted Zika virus has centered around heterosexual couples, due to the association with pregnancy risk, gay men and others who engage in unprotected anal sex should note that Zika virus can affect anyone.

“The take-home message is you have to consider any kind of intimate contact between an infected person with Zika and a non-infected person as a potential risk situation, regardless of gender,” Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota told STAT.

The CDC's announcement doesn't change the agency's recommendations for preventing the sexual transmission of Zika virus, which can be spread through semen and blood. Although Zika virus can live in saliva, it is not yet known if the virus can be transmitted from person to person that way.

Zika virus is still more serious for pregnant women

Pregnant couples need to be especially careful about avoiding Zika virus because of Zika's link to the birth defect microcephaly, which the CDC confirmed on Wednesday (doctors and scientists had long suspected that the diseases were linked). Babies born with microcephaly have smaller than normal heads and can have underdeveloped brains and cognitive problems.

If a man who has traveled or lived in an area with active Zika transmissions has a pregnant partner, the couple should abstain from sex during the pregnancy or use condoms until the baby is born.

But sexually transmitted Zika is dangerous for gay men too

While mosquitos are still the primary vector for spreading Zika virus, the new report hints that we have more to learn about other modes of transmission.

In addition to the Dallas case, the report provided information on six probable and confirmed travel-related Zika cases in the United States involving heterosexual couples.

"This suggests that sexual transmission of Zika virus might be more common than previously reported," the report authors wrote.

Because Zika virus's symptoms are often mild, many people who are infected don't even realize that they've had the disease. Still, men who have sex with men should care about protecting themselves from the disease. In addition to birth defects, Zika virus has been linked to two neurological conditions, encephalomyelitis and Guillain-Barré syndrome, in people recnetly infected with Zika.