DALLAS -- Texas on Monday reported its first case of Zika virus that likely came from a mosquito bite within the state.
Florida is the only other state in the U.S. with locally spread Zika. Health officials say that the woman who was infected in Texas is a resident of Brownsville, located on the border the state shares with Mexico. But health officials said she reported no recent travel to Mexico or any other country with ongoing Zika outbreaks.
Until the Florida cases, all the cases in the U.S. were connected to travel to countries with outbreaks, mostly in Latin America and the Caribbean.
"We knew it was only a matter of time before we saw a Zika case spread by a mosquito in Texas," Dr. John Hellerstedt, commissioner of the Texas Department of State Health Services, said in a news release. "We still don't believe the virus will become widespread in Texas, but there could be more cases, so people need to protect themselves from mosquito bites, especially in parts of the state that stay relatively warm in the fall and winter."
The Texas health department said there are currently no other homegrown cases, but health officials continue to watch for them. Zika is transmitted to people primarily through the bite of an infected mosquito, though sexual transmission can occur.
The Texas case was confirmed last week by a lab test. Officials say testing indicates the virus can no longer be spread from her by mosquitoes.
The woman is not pregnant. Infection during pregnancy can lead to severe brain-related birth defects.
Chris Van Deusen, a spokesman for the state health department, said the woman had fallen ill and gone to her doctor, who ordered the Zika test. Van Deusen said six members of the woman's household were also tested and do not have the virus.
Most infected people don't get sick. It can cause a mild illness, with fever, rash and joint pain.
Health workers will be going door-to-door in the area around the patient's home to educate the public, help people reduce potential mosquito breeding habitats and collect voluntary urine samples to find out if there are other infections.
Health officials for the state and Cameron County are working with the Centers for Disease Control and Prevention to investigate the case. State officials say further investigation is necessary to try to figure out how and where the woman was infected.
Officials have been trapping and testing mosquitoes to learn more about activity near her home. Brownsville has recently sprayed for mosquitoes in the area and will continue to work on reducing the mosquito population.
Through last week, Texas has had 257 confirmed cases of Zika virus disease. Until now, all cases in Texas had been associated with travel, including two infants born to women who had travelled during their pregnancy and two people who had sexual contact with infected travellers.
