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How Long Does Zika Survive In Bodily Fluids? Studies Can't Provide Much Reassurance


Ever since the start of the 2016 Summer Olympics and the Centers for Disease Control and Preventions unprecedented U.S. travel warning — issued earlier this week for a 150-square-meter area of Miami, Florida — Zika has worked its way back into the public eye. And while I could not find any concrete information regarding weather searches for “Zika virus” had increased over the last week, I can say that the amount of Zika-related information being disseminated appears to be on the rise. (At least it has been on my Facebook newsfeed.) But aside from mosquitos, how is Zika contracted? Can the virus be passed through semen or blood and, if so, how long does Zika survive in bodily fluids?

First and foremost, yes: Zika can be passed through bodily fluids. In fact, according to the CDC, Zika can be transmitted through sex, through a blood transfusion, through laboratory exposure, from mother-to-child, and — most commonly — via mosquitoes. The CDC has noted that not all bodily fluids have tested positive for Zika (for example, to date, breast milk appears unaffected); however, Zika has been found in blood, semen, vaginal fluids, and urine. As for how long how long Zika remains in these fluids, the answer to that question is a bit trickier (and still unclear).

MADISON, WI - JUNE 28: A research specialist at the AIDS Vaccine Research Labs at the University of Wisconsin-Madison processes blood samples taken from pregnant rhesus macaque monkeys infected with the Zika virus on June 28, 2016 in Madison, Wisconsin. Researchers at the University released a study today detailing how research at the facility has found the Zika virus persisted in the blood of pregnant monkeys for 30 to 70 days but only around 7 days in others. The study also found that monkeys previously infected with the virus were resistant to a second infection, which suggests the animals have a naturally occurring immunity. Health professionals in the United States are preparing for the possibility of an epidemic of Zika which can be transmitted by mosquitoes. (Photo by Scott Olson/Getty Images)Scott Olson/Getty Images News/Getty Images

Earlier this year, Slate published an article and — at the time of publication — data seemed to imply Zika could remain active in semen for up to two months, though in blood samples the virus could only be detected for one week. However, according to the most recent information out of the CDC, further testing is needed to determine exactly how long Zika remains present in bodily fluids:

Studies are underway to find out how long Zika stays in the semen and vaginal fluids of people who have Zika, and how long it can be passed to sex partners.

What the CDC does know, however, is that Zika lives longer in semen: "we know that Zika can remain in semen longer than in other body fluids, including vaginal fluids, urine, and blood." And, according to an update to the Interim Guidance for Prevention of Sexual Transmission of Zika Virus just last month, the longest period of time that Zika has been detected in a semen sample was 93 days.

As such, the CDC has recommended that anyone who lives in or travels to a known, and active, Zika territory use “condoms and other barriers [to] reduce the chance of getting [or spreading] Zika":

To be effective, condoms should be used from start to finish, every time during vaginal, anal, and oral sex.

The only other "safe" method is to abstain from sexual activity altogether.

The good news, or silver-lining is that, of the thousands of cases of Zika and the 1600 plus in the United States, at the time of the Zika virus update, only 15 had been transmitted by sexual contact in the United States, though sexual transmissions have been reported in other countries.