A person infected with Zika has died in Utah, and while the exact cause is unclear, authorities said Friday it marks the first death related to the virus in the continental U.S.

The unidentified Salt Lake County resident contracted the virus while traveling abroad to an area with a Zika outbreak, health officials said.

The patient who died in late June was elderly and also suffered from another health condition, according to the Salt Lake County Health Department.

The person had Zika symptoms — including rash, fever and conjunctivitis — but it’s unclear if or how the virus contributed to the death, said Centers for Disease Control and Prevention spokesman Benjamin Haynes.

Officials discovered the case while reviewing death certificates, and lab tests confirmed their suspicions, said Gary Edwards, executive director of the Salt Lake County Health Department.

Utah authorities refused to release additional information about the patient or where he or she traveled, citing health privacy laws.

The virus causes only a mild illness in most people. But during recent outbreaks in Latin America, scientists discovered that infection during pregnancy has led to severe brain-related birth defects.

It’s spread mainly through the bite of a tropical mosquito.

No cases of locally transmitted, mosquito-borne Zika have been reported in the continental United States, according to The Centers for Disease Control and Prevention.

But a 70-year-old man from the San Juan metro area in the U.S. territory of Puerto Rico died in late February. Officials said he recovered from initial Zika symptoms, but then developed a condition in which antibodies that formed in reaction to the Zika infection started attacking blood platelet cells. He died after suffering internal bleeding.

More than 1,100 Zika illnesses have been reported in the 50 states and the District of Columbia, including six in Salt Lake County, according to health officials.

Almost all were people who had traveled to Zika outbreak countries and caught the virus there.

But 14 were people who had not traveled to Zika zones but had sex with someone who had.