The Texas Department of State Health Services is urging residents to be on the lookout for measles.
So far there have been four confirmed cases in the last month and nine in the last year.
Health care providers should be on alert for potential exposures and patients with measles symptoms.
Measles is a highly contagious respiratory illness spread by contact with an infected person through coughing and sneezing. The Texas Department of State Health says measles is so contagious that if one person has it, 90 percent of the people close to that person who are not immune or vaccinated will also become infected with the measles virus.
State health officials urge immunization to protect against and prevent the spread of measles. People should check their immunization status with their health care provider.
The incubation period of measles is about two weeks from exposure to onset of rash. People are contagious from four days before onset of rash to four days after the appearance of rash. The rash usually begins on the face and spreads to the trunk. Other symptoms include fever (higher than 101 degrees), cough, runny nose and sore eyes.
The four most recently confirmed cases are from Tarrant County in North Texas. Other counties this year include Dallas, Denton and Harris.
Texas had no measles cases reported in 2012.