Welcome to Dear Julia, a column where readers submit everyday health questions. Which over-the-counter painkillers work best? Is it better to run or walk for exercise? Julia Belluz sifts through the research and consults with experts in the field to figure out how science can help us live happier and healthier lives.

Dear Julia: I have a trip planned to Brazil. Should I cancel because of Zika virus?

There's a lot of panic right now about the Zika virus — and it seems understandable.

For starters, this outbreak is different from, say, the Ebola scare that started two years ago. Ebola, after all, was extremely difficult to contract. Unless you exchanged bodily fluids with a person infected with the virus, you weren't going to get it.

Zika, by contrast, seems harder to avoid. The virus is spread by a mosquito that's common in South and Central America (as well as the southern United States and many other parts of the world). There are cases of local transmission — meaning mosquitoes are currently spreading the virus — in more than 20 countries and territories in the Americas right now, including the US territories of Puerto Rico and the Virgin Islands.

Zika is expected to reach nearly every corner of the Western Hemisphere very soon (except for Canada and Chile). And while the virus causes no symptoms in most people, it's also been linked to terrible complications: a birth defect that causes babies' brains to stop growing, as well as Guillain-Barré syndrome, a neurological condition that leads to paralysis.

All you need to do is get bitten by an infected mosquito to put yourself at risk. And since there's no cure for Zika, the only thing you can do to protect yourself is avoid mosquitoes in places where the virus is circulating.

That said, you don't necessarily need to move to a snowy outpost in Canada (too cold for mosquitoes) or even cancel your trip to Brazil (the center of the Zika outbreak right now). It really depends on your situation. Let's go through five different options:

1) If you're pregnant...

Consider postponing your trip to Zika-affected countries. Over the past year, pediatric neurologists in Brazil began to notice that some pregnant women infected with Zika have given birth to babies with a terrible birth defect called microcephaly, which is characterized by a shrunken head and incomplete brain development.

Since Zika arrived in Brazil in the spring of 2015, more than 4,000 cases of microcephaly have been reported in newborns born to mothers with Zika virus infection — a twentyfold increase from previous years.

Researchers are still trying to figure out how many of these birth defects were really caused by the virus, and whether the link is real (i.e., whether it's Zika and not some interaction with other viruses or environmental factor causing the damage to fetuses).

But until they do, based on the precautionary principle, the US Centers for Disease Control and Prevention is recommending pregnant women avoid travel to places with the virus. You can see this list for countries that currently have Zika travel advisories and expect that the CDC will keep adding more to the list as the virus spreads. And if you do cancel because of Zika, your airline may be offering a refund or credit, so make sure to ask about that.

2) If you're trying to get pregnant...

Proceed with caution. The CDC recommends consulting your doctor before traveling and following steps to prevent mosquito bites during the trip.

3) If you'd like to get pregnant someday (but not right now)...

No need to worry. Zika virus does not seem to pose a risk of birth defects for future pregnancies. As best researchers can tell, the virus clears itself from the body pretty quickly, remaining in the blood for only about a week after infection.

4) If you're a man with a partner who is trying to become pregnant...

It's possible that a man who travels to Brazil (say) and gets bitten by a mosquito carrying Zika could later transmit the virus through sexual intercourse. There have been two studies in the medical literature that suggest this is a risk.

In one case, a man who traveled to Senegal and contracted Zika gave it to his wife through intercourse after he returned home. In another, Zika was isolated from semen.

But there is a lot of uncertainty here. Researchers aren't sure how long Zika can remain in semen. And it's not clear how common sexual transmission actually is. Right now the evidence is pretty limited.

So consider this a potential risk. If you're a man trying to get your partner pregnant, and you travel to a Zika-infected region, you'll likely want to take precautions to avoid mosquito bites. Public Health England also warns men to wear condoms for about a month after traveling in countries where Zika has spread, and those who had unexplained fevers or a diagnosis of Zika, to wear condoms for six months. (So far, the CDC has said the evidence is too limited to issue a warning about this risk.)

5) For everyone else...

There's (relatively) good news for everyone else. The vast majority of people who contract Zika virus will never know they had it. Only 20 percent of people who get Zika even show symptoms of the disease.

For those who do show symptoms, the most common include a mild, flu-like illness: a low-grade fever, head and body aches, red eyes, and a body rash. More rarely, people with Zika report abdominal pain, nausea, and diarrhea. These symptoms usually show up two to 12 days after a mosquito bite, and they tend to go away within a week. Severe disease requiring hospitalization is uncommon, and death is rare.

As with any virus, however, your chances of complications with the virus increase if you have underlying medical conditions.

And there's one final concern: Health authorities have already noted an increase in Guillain-Barré syndrome associated with Zika. This is a neurological condition where a person’s own immune system damages the nerve cells, leading to muscle weakness or paralysis. The symptoms can last weeks or months. Most people recover fully — though it can take years to do so. In rare cases, people have died.

Again, though, researchers are studying this link, and a direct causal relationship has not yet been established. For now it seems to be a rare but potential complication of this virus.

A final caveat

There's one asterisk that should be placed on all of the above. Zika only rarely affected humans before the massive outbreak in Brazil began in 2015. This means we're only just now learning about the virus's full effects. It's also possible that the virus has mutated in such a way that it's now more harmful and that it impacts people differently than it did in the past. Alternatively, it's possible that the risks of complications like microcephaly have been under- or overstated. We still need more research here.

So for now, just be careful. And wear lots of bug repellent.

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