Health officials in one Texas county say they’ve received word that a traveler who recently visited Latin America contracted the Zika virus, a puzzling mosquito-borne illness that has collected lots of attention because it may be linked to a substantial rise in birth defects in Brazil.

Harris County Public Health & Environmental Services made the announcement Monday, saying the Centers for Disease Control and Prevention (CDC) confirmed the diagnosis.

Harris County encompasses Houston and is one of the country’s largest counties.

According to the CDC, the Zika virus is spread when an infected mosquito bites a person, usually triggering a mild illness that causes people to experience symptoms like fever, rashes and joint pain. Most people recover within a week, and there’s seldom any need for hospitalization.

However, the Brazilian Ministry of Health is currently investigating more than 3,000 cases of microcephaly, a disorder that causes children to be born with abnormally small heads. Brazil only saw 147 cases of microcephaly last year, but the numbers have surged since the Zika virus arrived in May and authorities are still working to see if there’s a direct link between the two.

The CDC has said there hasn’t been any indication Zika has been contracted in the United States, though there have been multiple cases of people getting infected while visiting a foreign country and returning home. Officials didn’t indicate when or where this traveler got infected.

The virus has caused outbreaks in at least 12 countries in North and South America, according to the CDC, as well as many others in Africa and Southeast Asia. In late December, the CDC issued a travel notice for Puerto Rico after the island identified its first locally-acquired Zika infection.

The CDC asks people traveling to Puerto Rico — and other countries where Zika is present — to take proactive steps to safeguard themselves from mosquito bites, like wearing insect repellant and wearing long sleeves and pants. But the organization says the virus will likely continue to reach new territories because the specific kind of mosquitos that spread it live across the globe.

That type of mosquito — the Aedes species — are present in Harris County, according to the county Public Health & Environmental Service’s website. The agency echoed the CDC’s calls for travelers to take preventative steps when they’re traveling to nations where Zika is found.

There’s currently no vaccine against the virus, the CDC says.