FORT BEND COUNTY, Texas -- A second round of testing on students and staff at George Bush High School in Fort Bend resulted in 10 new positive TB cases being identified, officials confirmed Wednesday.

Fort Bend County Health and Human Services says it is continuing the investigation of contacts to active tuberculosis at the campus.

A previous mass screening in June led to 10 active cases being discovered, bringing the August total to 20 cases.

"It is not possible to determine if all 20 infections are related to the active cases at George Bush High School or from other exposures. However, all can be evaluated and offered preventive medication," FBCHHS stated in a press release. "As a reminder, a positive test does not mean that the person is ill with active TB disease; it simply means that they have been exposed to the bacteria and are infected."

TB info from FBCHHS:

Tuberculosis is a disease caused by bacteria. It typically causes a disease of the lungs, but can affect other organs of the body. While tuberculosis can spread from person to person, it usually takes prolonged close contact with a person with active disease. It cannot be spread as easily as a cold, or flu or measles, but may be spread if droplets containing the bacteria, coughed or sneezed into the air, reach the lungs of another person. Symptoms of tuberculosis include persistent and productive cough lasting more than two weeks, unexplained fevers, night sweats, unexplained weight loss or coughing up blood. Anyone with those symptoms should go to their health care provider. Others who are not considered at risk, but who just want testing, may visit their private physician.

As part of the mandatory testing, hundreds of students and dozens of faculty members were told they would not be allowed to start the school year unless they came to campus early for the tests.

Related: 16 TB cases linked to Bush High School

Related: TB testing once mandatory for all Texas students

Treatment for TB must be monitored by the health department and can last up to two years.

Drug-resistant strains of TB have become more prevalent in recent years. These untreatable strains have been present in Fort Bend County in the past.