100 high school students of Nimitz High School in Irving were tested for tuberculosis after a student was reportedly diagnosed with the contagious disease. The high school students shared a class with the tuberculosis positive student last spring.

The unnamed student reportedly showed symptoms of tuberculosis this season. She is currently being treated and is expected to do fine.

According to the Medical Director of the Dallas County Health Department's TB clinic, Dr. Gary Woo, 40 to 60 people get tested in the clinic for the contagious disease everyday. Last year, Dallas County had a total count of 180 people diagnosed with TB.

"It's uncommon unless your body is weak or your immune system is compromised," Dr. Woo said in a report by CBS Local.

Other parents of Nimitz High School students who were not exposed to the tuberculosis positive student still had their children tested for the disease. According to them, it is better to be safe and to avoid spreading the disease to other kids in the house.

Tuberculosis is a disease caused by a bacterium, Mycobacterium tuberculosis, which usually attacks the lungs. It is a fatal disease that was once the leading cause of death in the United States, says the Centers for Disease Prevention and Control.

The disease can be spread through the air such as when one infected individual coughs, sneezes, speaks or sings. However, it is not spread by shaking someone's hand, sharing food or drink, touching bed linens or toilet seats, sharing toothbrushes and kissing.

Symptoms of tuberculosis include a bad cough that lasts 3 weeks or longer, pain in the chest, coughing up blood or sputum, weakness or fatigue, weight loss, having no appetite, chills, fever and sweating at night among others.

Testing for tuberculosis infection can be done through the TB skin test (TST) or the TB blood test. The 100 high school students from Nimitz High School were tested for tuberculosis through TST Wednesday. Results are expected to come out by Friday.