Editor's note: This story has been updated with comments from a Thursday afternoon news conference by the Austin/Travis County Health and Human Services Department.
Travis County health officials on Thursday confirmed the first case of the Zika virus in the county.
A man under the age of 50 contracted the illness while traveling in Colombia, according to the Austin/Travis County Health and Human Services Department.
On Tuesday, Dallas County officials confirmed the first sexually transmitted case of the virus. It also was the first confirmed case of a person contracting the virus within the continental United States.
Researchers have warned Zika could be linked with microcephaly, a condition causing children to be born with abnormally small brains and skulls. The World Health Organization on Monday called the virus a public health emergency, and the federal government has listed more than 20 Latin American countries, including Brazil, where public health officials say there have been roughly 4,000 reported cases of microcephaly since October and to which they are urging pregnant women not to travel.
The mosquito that carries the virus is endemic to Central Texas, but mosquito activity is low during the coldest months, according to Travis County health officials.
Jeffery Taylor, senior epidemiologist at the Austin/Travis County Public Health and Human Services Department, said at a Thursday news conference that 12 other people in the area who are ill and have recently traveled are also being tested for the virus.
While the Dallas County case is the only locally transmitted Zika virus infection, Taylor said mosquito movement will be closely monitored in the coming months.
“As temperatures get warmer in spring and summer, we’ll be monitoring what happens in Mexico, and if the virus appears to be moving northward, closer to Texas, the state health department will be monitoring whether we have cases in south Texas and the Rio Grande Valley,” he said. “If the outbreak evolves and affects Texas, I expect it will be south Texas first. But it’s already affecting Texas due to travelers.”