The mosquito-borne Zika virus making headlines in Brazil has reached Puerto Rico. Authorities said Thursday they had diagnosed the first such case there in an unidentified patient who had not traveled in recent weeks, the Associated Press reported. The discovery prompted the U.S. Centers for Disease Control and Prevention to publish a low-level travel notice warning people to be hyperalert and protect themselves.

Local officials spoke up as well. “There is no reason for alarm, and the public should continue to take common-sense steps to avoid mosquito bites, like using repellent and wearing long pants and shirts,” Puerto Rico’s Resident Commissioner Pedro Pierluisi said in a statement. He added that he anticipated medical personnel would visit the U.S. territory this month to teach doctors about the virus.

The Zika virus causes Zika fever, a comparatively mild disease that afflicts a person about three days after being bitten by a diseased mosquito. The illness lasts as long as a week and can be associated with rashes, headaches and conjunctivitis, according to the World Health Organization

However, the Zika virus has recently attracted attention in South America because it may be connected with a rise in the number of babies being born with microcephaly, meaning they have abnormally small heads because of incomplete brain development. Experts are investigating whether there’s a link.

“We don’t know if it’s only Zika or if it’s a combination of Zika, dengue and chikungunya,” Marco Collovati, founder of Brazilian diagnostics company OrangeLife, told the New York Times this week. “Maybe a woman was infected by dengue a year before, and now is pregnant and gets Zika.”

Besides Brazil, Zika infections have been found in Chile, Guatemala, Mexico, Panama and Paraguay, among other countries, CBS News reported. The CDC recommends that travelers avoid pools of standing water, employ strong bug sprays and use either mosquito nets or window screens to keep the insects at bay.