The much-talked-about Zika virus has now been transmitted by something other than a mosquito.
Zika has been sexually transmitted in Texas, according to the Centers for Disease Control and Prevention and Dallas County health officials. Dallas officials say a local resident was infected with the virus by having sex with someone who had contracted the disease while traveling in Venezuela.
This is reportedly the first U.S. case of Zika transmission.
This isn't a complete shock. Health officials had suspected Zika transmission through sexual contact or blood transfusion might be possible.
CDC Director Tom Frieden told CNN, "There have been isolated cases of spread through blood transfusion or sexual contact, and that's not very surprising. The virus is in the blood for about a week. How long it would remain in the semen is something that needs to be studied and we're working on that now."
CNN reports that before the Dallas case, there were two documented cases linking Zika to sex. In French Polynesia during the Zika outbreak in 2013, semen and urine samples from a Tahitian man tested positive for the virus even when blood samples didn't. In 2008, a Colorado microbiologist contracted Zika after traveling to Senegal. A few days later, his wife contracted the disease even though she wasn't exposed to any mosquitoes carrying the viruses and hadn't left Colorado.
Health officials say they plan to study all areas of transmission for the Zika virus, which has now spread to nearly 30 countries and regions.
"What we know is the vast majority of spread is going to be from mosquitoes," Frieden told CNN. "The bottom line is mosquitoes are the real culprit here."
The CDC has issued interim recommendations to prevent sexual transmission of the Zika virus:
For pregnant women, and men with pregnant sexual partners who live in or have traveled to Zika-affected areas:
Discuss the male partner's potential exposure to the virus and any history of Zika-like illness with the pregnant woman's health care provider.
If men with a pregnant sex partner reside in or have traveled to Zika-infected areas, they should use condoms during all type of sex or abstain from sexual activity during the pregnancy.
For non-pregnant women, and men with non-pregnant sexual partners who live in or have traveled to Zika-affected areas:
Consider using condoms during sex or abstaining from sexual activity.
“Now that we know Zika virus can be transmitted through sex, this increases our awareness campaign in educating the public about protecting themselves and others,” said Zachary Thompson, Dallas County Health and Human Services director, in a statement (pdf). “Next to abstinence, condoms are the best prevention method against any sexually-transmitted infections.”
The Zika virus can be transmitted from a pregnant mother to her baby during pregnany or around the time of birth. The result is often infants born with microcephaly, which is a reduced head size in infants. Because of the connection, the CDC recommends that pregnant women and women trying to become pregnant avoid traveling to countries with a known Zika transmission.
Only about one in five people affected with the virus will get sick, according to the CDC. For those who do get sick, the symptoms are typically mild: low-grade fever, rash, joint pain, headache and conjunctivitis (red, itchy eyes). Although there have been no reported deaths, according to the World Health Organization, the virus can be difficult to diagnose.