DENTON (CBSDFW.COM) – A Denton High School student again tested positive for active tuberculosis in the second round of more specialized screening for the disease, county health officials said Tuesday afternoon.

The Denton Independent School District began taking precautions immediately after skin tests taken on Oct. 5 pointed toward the 16-year-old having tuberculosis.

He was a transfer student from Ennis High School, where hundreds of students and staff had to be tested after a science teacher discovered he spent a year in the classroom with an active case of the disease.

Denton ISD officials began testing high school students and school staff who had extended contact with the 16-year-old on Oct. 11.

On Oct. 20, the district announced chest x-rays performed on the 300 individuals showed no new cases of tuberculosis and “no indication of a school-based outbreak of TB.”

“Repeat skin testing will be completed on all household, close and school-based contacts in early December to verify the results,” district spokeswoman Sharon Cox said in a press release.

Secondary tuberculosis testing involves screening samples obtained after the patient deeply coughs. Results take about three weeks and offer a more specialized view of whether the disease is contagious – active – or not.

It is possible to be exposed to inactive, not contagious tuberculosis germs.  Each type of TB can be treated with medicine.

Tuberculosis is an airborne disease that primarily targets the lungs, but could spread to other parts of the body. The 16-year-old in question was hospitalized after suffering a deep cough, major fatigue and rapid weight loss, his mother said.

“You may think they’re on diets, but no, it wasn’t the case,” mother Melissa Sosa said on Oct. 5.

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