Tuesday afternoon, the first confirmed case of the Zika virus was found in Dallas. That comes after Monday’s discovery of the virus in Bexar County, and at least seven previously confirmed cases in Houston. At this point, it seems likely that the number of Zika cases in Texas is only going to go up.

Because we love to panic about new diseases (though Zika, which has been present in Africa and Asia since the late 1940’s, isn’t really new so much as it’s new to the West), “Zika outbreak in Texas” makes a good headline. But before panicking, it’s worth clarifying exactly what Zika is, how it’s transmitted, and what the symptoms are.

What is Zika?

The Zika virus was first discovered in 1947 in the Zika Forest in Uganda. That’s where the name comes from, and it’s where the virus stayed—for the most part—until very recently. Zika traveled narrowly along the equator in Africa and Asia until 2007, when it broke out on the island of Yap in the Pacific. From there, it spread, culminating in a massive outbreak in 2015 in Central and South America. Currently, there are as many as a million suspected cases of Zika in Brazil alone.

The symptoms of Zika aren’t typically serious—it’s like dengue fever, but with milder symptoms. Most people experience fever, a mild rash, some point pain, and redness in the eyes. But there’s one group that’s at much greater risk of consequence from the disease: People who are pregnant, who could find themselves giving birth to babies with a neurodevelopmental disorder known as microcephaly (which results in babies being born with abnormally small brains and heads).

That’s the major concern about Zika. Nobody wants to come down with a fever or a rash, but Zika wouldn’t be terrifying if it didn’t have potentially serious consequences on developing fetuses. Those consequences led El Salvador to urge women to avoid pregnancy (though in a country with no legal means to access abortion, and very limited access to contraception, avoiding pregnancy falls as much on men as it does women). The link between microcephaly and Zika is thus far unproven, but the numbers suggest some correlation: more than 4,180 babies are suspected to have been born with microcephaly in Brazil in the past year. (Experts suggest that number may drop as the cases are investigated.)

Beyond the risks to pregnant women, there’s a suspected link between Zika and a neurological disorder called Guillain–Barré syndrome, which affects adults. This risk is similarly unproven, but the Center for Disease Control explains:

Guillain-Barré syndrome (GBS) is a rare disorder where a person’s own immune system damages the nerve cells, causing muscle weakness and sometimes, paralysis. These symptoms can last a few weeks or several months. While most people fully recover from GBS, some people have permanent damage and in rare cases, people have died.

We do not know if Zika virus infection causes GBS. It is difficult to determine if any particular pathogen “caused” GBS. The Brazil Ministry of Health is reporting an increased number of people affected with GBS. CDC is working to determine if Zika and GBS are related.

In other words, Zika is not a serious virus, but there are possible (though yet unproven) potentially serious complications for both pregnant Texans and for otherwise healthy adults. It’s worth noting that the number of cases of both GBS and microcephaly are very low compared to the total number of cases of Zika—less than one percent—but as we learn more about Zika, those are the primary concerns.

How is Zika transmitted?

Mostly the virus is transmitted by mosquitos, which explains why it’s a serious problem in warm parts of the planet. Meanwhile, we get headlines like “US Is Probably Safe From A Zika Virus Outbreak — Except The South” (note: the South actually is part of the U.S.). Mosquitos thrive in warmer environments, and the little buggers are effective transmitters of blood-borne disease. But that’s not the only way Zika is transmitted: the case discovered in Dallas today was the result of sexual transmission. That’s a new discovery that the CDC only reported for the first time last month, and the incident in Dallas appears to be the first sexually transmitted one in the U.S.

What that means, in practical terms, is that those who want to remain Zika-free should take two precautions: Use bug spray (DEET is still the most effective mosquito repellant) and use condoms, even with an exclusive partner.

Who’s at risk?

Like most communicable diseases, the more cases of Zika there are, the more there are likely to be. Unseasonably warm weather in Texas doesn’t help any, either (though temperatures are expected to drop this week, which should chill the mosquitos out). So right now, the risks are higher in Houston than in Dallas, Austin, or San Antonio, since there are more confirmed cases there. But Houston, Dallas, and San Antonio make up a pretty small triangle with a fair amount of traffic between the two, so it’s unlikely anything is likely to stay in one part of Texas. That means that keeping the numbers low by prevention—i.e., mosquito repellant and condoms—is a good idea even in places that have yet to experience any confirmed cases.

At the moment, there’s no vaccine for Zika, though that’s likely to change at some point—major European drug companies are racing to create one, anyway. That’s probably going to matter a lot more for people in Brazil and other places where the virus threatens to reach pandemic proportions than it does for Texans.

Worrying about Zika isn’t the most productive use of anybody’s time in Texas, ultimately—but being aware of it, and practicing mosquito bite prevention, is a good idea nonetheless. The risks are small to most of us, and the number of cases isn’t yet troubling, but why take an unnecessary risk just to allow mosquitos to bite you?