How is the Zika virus spread through sex? Dr. Sanjay Gupta's Facebook chat

Dr. Sanjay Gupta met with the man who had the first documented case of Zika virus in the U.S. 8 years ago. Want the latest scoop on Zika and what we know? Dr. Gupta is live on Facebook to take your questions. CNN.com/Zika

Posted by CNN on Tuesday, February 16, 2016

Story highlights

  • The Zika virus is primarily spread through mosquitoes and sexual activity
  • WHO finds no relationship between pesticides and microcephaly
  • Dr. Sanjay Gupta answers people's concerns about the virus in a Facebook chat

Atlanta (CNN)As more cases of Zika virus are being reported, it's important to be up to speed on the facts, especially with misinformation spreading around.

Dr. Sanjay Gupta, CNN's chief medical correspondent, continues follow the developments and updates with Zika, and once again took to Facebook to answer questions about it.
Here are some of the questions and answers from his latest chat, edited for brevity and clarity:
1. How is the Zika virus able to be spread through sex?
Certain places in our bodies are "immune privileged," meaning that the immune system doesn't attack that area. One of those places is the testicles, where semen is produced.
A virus can live in the testicles more safely and for longer periods, which makes it more likely to be sexually transmitted. It may be designed this way so the immune system won't affect the chances of being able to reproduce.
While we don't know how Zika can can live in semen, we do know that Ebola can live there for long periods. When you hear about viruses being sexually transmitted, it happens because of the notion of immune privileges.
2. Could pesticides be a possible cause for increased cases of microcephaly?
The World Health Organization looked into this and found that there isn't a relationship between pesticides and microcephaly, the neurological birth defect that seems to be linked to the Zika virus.
It actually hasn't been confirmed for sure that Zika causes microcephaly, but the evidence is mounting because the virus was found in amniotic fluids and brains of those with the defect. If you are pregnant, you should avoid going to places where Zika is circulating.
3. Why are cases of Zika suddenly surging now?
The first documented case of the Zika virus in a primate was in the late 1940s. It was found in humans in the mid-1950s. Now we live in a globalized world. People can hop in airplanes and fly anywhere.
Most likely this virus made the jump in someone's body. Someone got infected, got on a plane and traveled somewhere where the mosquito that spreads Zika was present. In 2007, 73% of the tiny island of Yap in Micronesia got infected. Talk about viral. That's what it means to go viral. From there, it went zigzagging and hopscotching around the world.
If your body has never seen a virus, you have no immunity to it and you can spread it to someone else. The more naive the population is to a virus, the more likely it is to spread.
Even if you don't get sick from it, you could be considered a carrier. In South America and in other places around the world, there are many carriers because this is the first time so many people have been exposed to this virus.
4. What is the incubation period of Zika in mosquitoes?
Once the mosquito bites someone with Zika, that person will digest and process that virus for at least 14 days before they can infect someone else with it.
The average life span is of the mosquito is 30 days, so it really takes half their life to process the virus. This actually leads to whole area of research of trying to shorten the life of a mosquito so it doesn't have time to process the virus.
5. Are people with compromised immune systems more susceptible to Zika and should they take extra precaution?
If you have a compromised immune system, it's prudent to be even more cautious. That's part of the reason why elderly people are more at risk for getting sick; their immune systems don't work as briskly. Same is the case for very young people.
It's worth stressing that four out of five people who get Zika will have mild or no symptoms. So even if you get infected, doesn't necessarily mean you will get very sick. Even for pregnant woman: While you should avoid it, even if you get it, there is no guarantee you will develop problems with microcephaly.
We don't know what the likelihood is, but it's probably much lower than we think. There are likely a lot of pregnant women who had Zika and had perfectly normal deliveries.
6. What are chances the Zika virus will mutate?
Viruses are constantly mutating. That's why we have a flu shot every year, because different strains spread each year and are always changing. We know Ebola changed several times.
The concern is that it will mutate to something more likely to kill or spread, but the mutation overall is just a natural evolutionary process.
7. If a woman wants to have children, how long should she wait after getting Zika before she gets pregnant?
The virus appears to leave the body after around seven days. No evidence that if you had Zika, a future pregnancy will have any risk. In fact, you will likely be immunized after you get it. The concern is for women who are currently pregnant, not who get pregnant in the future.
8. During which trimester is a pregnant woman with Zika most at risk for having a child with microcephaly?
We don't know all the answers, but looking at all the data, it appears there is more a greater risk earlier in the pregnancy. But the guidance is that if you are pregnant, no matter how far along, there is a risk.
If you don't have to be in a place where Zika is spreading, don't go there while you are still pregnant.
9. What kind of precautions need to be taken ahead of the Olympics?
For vast majority of people going to the Olympics in Rio de Janeiro, there's minimal risk. In August, the concern of mosquitoes are lower in Brazil than during their summer (August is during their winter).
Standing water is really the enemy. The Olympic committee is taking measures to reduce standing water where mosquitoes can breed. That even means a small bottle cap size of water. They are also using certain insecticides.
One of the questions is whether the insecticides are safe for pregnant women. The head of the CDC tells me there's no cause to worry from these insecticides because you don't absorb enough across the skin for there to be enough of a problem. Basic precautions should be taken such as insecticides, long sleeves and removing standing water where mosquitoes like to breed and live.
10. Will people be quarantined after traveling back from places that carry the virus?
This is a virus that primarily spreads from mosquitoes and sex. Quarantine won't make a difference. One who goes to the supermarket with Zika won't be a risk to other shoppers.
If a man with a pregnant wife travels somewhere where Zika is spreading, then the guidance is to be abstinent or practice absolutely safe sex during the rest of the pregnancy.