When we first started hearing about Zika virus, the big focus was on the fact that it spread through sexual transmission, which made it clear that Zika can live in multiple bodily fluids. As it began to spread via mosquitoes here in the United States, the picture of Zika transmission became a little foggier: just how many bodily fluids can Zika live in, and how can you take the proper precautions?
There are actually more ways to transmit Zika than we originally thought: not only can the virus be transmitted through sex and mosquitoes, but it can be passed from mother to child, which is why there's so much fear about pregnant women contracting the virus. Zika has been linked to several birth defects, so women who are or may become pregnant are being warned to take extra precautions and actually avoid traveling to areas where Zika is — including, for the first time ever, a travel restriction within the continental U.S. (one town in Florida) by the U.S. government.
It can also be spread through blood transfusions — this hasn't happened in the U.S. yet (that we know of) but it happened in Brazil. Blood donors are usually thoroughly screened, including with questions about places they've traveled in the last year — and that would have to include places like Brazil, French Polynesia and, well, Miami.
Since it's the middle of summer, most of us are swatting away mosquitoes purely out of annoyance and, in many places, out of fears of Zika. Mosquitoes pick up the virus from biting a person who is infected. Then, they spread it to someone else when they bite again. Zika certainly isn't the only — or the worst — disease that you can get from a mosquito bite, but it's definitely one that has made people wonder how mosquitoes get the diseases in the first place.
Mosquitoes are vectors for disease, which means that they can spread whatever it is they're infected with, but they don't actually get the disease themselves. So, a mosquito that is carrying Zika doesn't actually have Zika — it's just kind of like a high-speed, sneaky, flying syringe full of the virus that could infect you.
It's pretty scary to think about, but scientists know for sure that a pregnant woman who is infected with Zika can pass it on to her unborn baby — the problem is, they don't know exactly how it happens. It probably happens close to when the baby is born, during childbirth, or shortly thereafter (because there are lots of body fluids involved — mucus plugs, blood, urine, feces — you name it).
If scientists can't pinpoint the exact mode of transmission, they have to be on the defensive and postulate that it could be any number of ways. One theory is that the virus can actually get through the placental barrier, and this may be made easier by inflammation in the mother's body caused by Zika, which makes her immune system less able to effectively protect the fetus.
Another theory wonders if Zika might be able to hide inside other cells in order to pass through the barrier to the fetus — like a Trojan horse, basically. The study that looked into this theory also pointed out that this might not be possible all of the time, so therefore, not every mother infected with Zika would pass the virus on to the fetus, which seems to correlate to what we know about the risk of Zika in babies of mothers who have been confirmed to have the virus.
Sex: Semen & Saliva
We know that no matter who you're having sex with, male or female, it's possible to transmit Zika virus through intercourse — but there are a lot of body fluids involved here, so which ones are actually responsible for carrying the virus?
All of them, as it turns out — but the virus doesn't live in all of them for the same length of time. The virus can stay in semen for the longest time of all, meaning that if a man has sex with multiple partners in a particularly short space of time after he's been infected, he's going to be capable of spreading the virus to multiple people. Research is currently looking into just how long it's possible for Zika to be transmitted through semen, but it could be a pretty long time. But the virus can also live in vaginal fluids, albeit for a shorter time, so women can spread to their partners through sex, too.
For shorter periods after infection, Zika can live in salvia, making it transmittable during kissing and oral sex.
Other Body Fluids — Especially Kid Ones
Urine and feces are just a part of life when you're a parent, and yep, you guessed it: Zika can live in pee and poop, too. It doesn't mean that your child will be more likely than anyone else to get Zika — we're all unwittingly exposed to particles of urine, feces and vomit without knowing it on a pretty regular basis! — but it does mean that paying special attention to hand washing is a must.
But like, Zika aside — shouldn't we wash our hands a lot anyways?!