HOUSTON – A pregnant woman, who recently lived in El Salvador, has tested positive for the Zika virus, according to the Legacy Community Health on Thursday.

This is the first patient to test positive at the health center.

The woman had lived in El Salvador, where the virus is widespread, prior to coming to the U.S. earlier this year. However, it’s not clear whether she contracted the virus directly through a mosquito bite in El Salvador or through sexual transmission with a male partner.

Either way, the Centers for Disease Control has said definitively the virus can cause severe birth defects.

“We are closely monitoring the patient through her pregnancy and hope for the best for mom and baby,” said Dr. Natalie Vanek, a Legacy Community Health infectious disease specialist. “Today we are re-issuing our advisory to pregnant women not to travel down to the Central and South American countries where the virus is rampant, and want to make the broader Houston community aware the virus can be transmitted sexually. We are focused on prevention, not panic."

Last week, the CDC said sexual transmission “might contribute to more illness than was anticipated when the outbreak was first recognized.”

The guidance comes after a couple in Dallas County – now known to be two men – became infected with Zika in January. It was the first report of transmission by men having sex with men, while previous sexual transmission focused on heterosexual couples.

Still, the focus remains on pregnant women.

About 700 cases of Zika virus have been reported in the United States, including almost 70 pregnant women, according to the CDC.

Legacy Community Health say they see about 300 pregnant women a day, some of whom travel regularly to Latin America.

Zika symptoms include fever, rash, joint pain, or red eyes.

The best prevention methods are avoiding mosquito bites by using insect repellant, wearing additional clothing, staying in air-conditioned spaces, and using condoms during sexual activity.