Texas health official reported the state's first case of Zika virus transmitted by local mosquitoes on Monday (28 November). It makes Texas the second US state to be affected, after Florida, since the outbreak in Brazil last year.

More than 230 locally-transmitted cases of the birth-defect-causing virus have now been reported in Florida and, as such, the first-known case in Texas has not come as a surprise to state health officials.

"We knew it was only a matter of time before we saw a Zika case spread by a mosquito in Texas," Dr John Hellerstedt, Texas Department of State Health Services commissioner, said in a statement.

"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 case involved a woman living in Cameron County near the Mexican border, the statement added. It also confirmed that the woman was not pregnant, which is the primal concern with the virus as it causes children to be born with abnormally small heads, indicating their brains have stopped growing normally.

Officials confirmed they have assessed the woman's home, and are trapping and testing mosquitos to understand how the virus is spread in local mosquito populations, Reuters reported.

Experts believe the spread of the virus will be slow in winter months, but will ramp up when temperatures begin to increase again. Nikolaos Vasilakis, of the University of Texas Medical Branch, told Buzzfeed: "It will be interesting to see what's going to happen in late spring."

There is no vaccine or treatment for Zika, which spreads by mosquito bite and sexual contact. The virus causes mild fever, rash and red eyes. However, an estimated 80% of sufferers have no symptoms, making it difficult for individuals to know if they have been infected.