Omar Villafranca, NBC 5 News
Health officials say fewer than 5 percent of the approximately 270 people tested had positive test results for exposure to tuberculosis.
Some of the nearly 300 Denton High School students have tested positive for exposure to tuberculosis.
Sarah McKinney of the Denton County Health Department would not provide exact numbers but said the number of students who tested positive to exposure "was under 5 percent."
"As anticipated, an extremely small number of positive reactors were identified from the readings, and there is no evidence of a school-based outbreak of TB," she said a statement Thursday. "Because of the minimal number of positive reactors, the exact results will not be released to protect the privacy of the individuals."
Hundreds of people at Ennis High School in Ellis County tested positive for exposure to tuberculosis after a teacher was diagnosed with an active case of the bacterial infection in August.
A positive skin test mean that the students tested positive for exposure to the bacteria. It does not mean the students have tuberculosis. People who test positive for exposure to tuberculosis are not contagious.
The health department said it tested approximately 270 students and staff.
McKinney said the average number of positive reactions to be expected from skin testing is 7 percent, higher than the less than 5 percent found in Tuesday's tests.
"There is no reason to believe this is a TB outbreak," she said in an email.
The Denton County Health Department conducted the testing Tuesday after a student who attended Ennis High School last school year was hospitalized with a suspected case of tuberculosis. Those tested included people who had class or rode the bus with the student.
As a precaution, health officials will also be back in eight to 10 weeks to retest the Denton High students who tested negative to confirm those results.
Tuberculosis is an airborne bacterial infection, but people are only at risk for contracting it if they are in close proximity to a person with an active case for a prolonged period of time -- 40 to 80 hours over the course of several weeks.
A University of North Texas student has a suspect case of tuberculosis, but health officials said the case is not related other recent cases in Denton and Ellis counties.
If you have questions or concerns about tuberculosis, email them to firstname.lastname@example.org. To see the questions we have already answered, click here to read "What to Know About Tuberculosis."