On Friday, scientists detected Zika virus in both urine and saliva for the first time, classifying the virus in the bodily fluid samples as "active." That means the fluid samples are capable of transmitting Zika. This finding, coupled with recent reports of a sexually transmitted Zika case in Texas, indicates that sexual contact may become a significant mode of transmission for the disease.
The conclusion bodes poorly for the most impoverished women in Brazil and other Latin American countries, where access to comprehensive sex education and reproductive care -- including abortion -- is spotty to nonexistent.
While Brazilian researchers cautioned that it was too soon to say whether the virus can be transmitted via urine or saliva, the U.S. Centers for Disease Control and Prevention affirmed Friday that sexual contact was a mode of Zika virus transmission.
"That fact that the virus was found with the capacity to cause infection is not proof that it can contaminate other people through those fluids," Myrna Bonaldo, one of the scientists at Brazil's Oswaldo Cruz Foundation who made the discovery, told Reuters.
Dr. Paulo Gadelha, the president of Oswaldo Cruz Foundation, which is part of the country's health ministry, reminded Brazilians that Aedes aegypti mosquitos remain the primary vector for transmitting the virus, but that didn't stop him from warning pregnant women not to kiss strangers at the Carnival celebrations kicking off tonight, Reuters reported.
"In light of the possibility of being in contact with someone who is infected, do not kiss, obviously," Gadelha said. "We cannot say today that there is no possibility of transmission."
New sex guidelines for pregnant women
The discovery comes days after the Dallas County Health and Human Services Department reported the first case of sexually transmitted Zika virus in the United States, after a patient contracted the virus from a sexual partner who had recently returned from Venezuela. On Thursday, Brazil reported the first Zika infection from a blood transfusion, and urged prospective donors to delay donations a full 30 days after recovering from a Zika infection.
After the Dallas report, the U.S. Centers for Disease Control and Prevention updated its Zika virus public health recommendation. Until the agency knows more about how the virus can be spread, it's advising pregnant women to avoid traveling to the 30 countries and territories with active Zika transmissions.
If a pregnant woman's male sexual partner lives in or travels to an area with active Zika transmissions, the agency recommends using condoms for vaginal, anal and oral sex during her pregnancy.
Women trying to conceive should consult their health care providers before traveling to any areas with ongoing Zika transmissions and should adhere to the strictest standards of mosquito bite prevention.
"The potential hazard to the fetus is so substantial and so tragic that this looks like a very prudent recommendation until we learn more,” Dr. William Schaffner, a professor of preventive medicine at Vanderbilt University Medical School, told The New York Times.
Poor women most vulnerable to sexually transmitted Zika
Still, the implications of sexually transmitted Zika are quite serious for a population that struggles with teen pregnancy and a dearth of sex education.
According to a 2014 government health report, teenage pregnancy rates are driven by high figures in Brazil's northeast region -- the same area that's been hardest hit by Zika virus. Of those teenage mothers, about 1 percent -- or 30,000 girls -- are between the ages of 10 and 15.
Sex education in Brazil is disjointed and controversial, according to Al Jazeera America, unsurprising in a heavily Catholic country with strict abortion law. Under such circumstances, women with fewer resources for disease prevention, care and treatment will be disproportionally affected by Zika (and, should the link between the two be proven, microcephaly), according to Brandon Brown, an assistant professor at University of California, Riverside's Center for Healthy Communities.
"If the United States is anything like the rest of the world, what we see is that high-income couples delay childbirth or adoption until an older age, compared to their lower-income counterparts," Brown said.
"This results in fewer children for high-income women. Low-income women may have fewer resources to prevent pregnancy compared to women with a higher income," he said. "Therefore, even for those intending to follow the mandate to not get pregnant, they may be unable to do so due to lack of resources."
That's true for Hilda Venancio Silva, whose three-month-old son was born with microcephaly. Silva, 38, had to seek out information about birth control on her own. “To be honest, I never had any education about it,” Venancio told Al Jazeera America.
"It is true that many infectious diseases do have a higher impact on low-income individuals and in low-income settings," Brown said. "HIV and TB are good examples of this. Not only does a high disease burden fall on low-income individuals, but it also historically falls on lower-income countries."