The Irving school district will test staff and students for tuberculosis exposure at a second high school in two months.
Dallas County health officials are conducting the testing at MacArthur High School after a student there was diagnosed with the bacterial infection.
The student, who attended MacArthur this semester, is at home and is getting treatment. The district can't identify what grade he or she is in for privacy reasons.
Approximately 80 students and teachers who have had the closest contact with the infected student can get tested for exposure to tuberculosis on Tuesday for free. The high school has 2,700 students.
"They don't expect any other students to be infected here at the school," district spokeswoman Lesley Weaver said. "They believe this is a student who has been exposed outside of Texas and unfortunately got sick."
The school district does not believe the case is related to an earlier case at Nimitz High School.
The Dallas County health department will return to the school on Thursday to administer the results.
"If there is a certain percentage of those who test positive for exposure, then they will expand the number of students they feel need to be tested," Weaver said.
Alexis Carney, a senior, said she hopes the testing will be enough to prevent an outbreak at the school.
"I think it's a good idea," she said. "My only issue is, I think we're not doing enough for it."
Casual contact does not lead to tuberculosis infection.
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"What the health department tells us, how they explain, is that you have to be in really close contact for prolonged periods of time -- really, day after day, hour after hour -- exposure, so even these 80 kids, it's really just precautionary," Weaver said.
The Irving Independent School District is hoping for the same outcome it got at Nimitz High School last month. One student had to be treated for the contagious disease, but health officials determined that tuberculosis had not spread to other students or staff.
The MacArthur students and staff who may be at risk for exposure to tuberculosis met Monday during school to learn more about Tuesday's testing.
Parents packed the high school's cafeteria Monday evening for a community meeting about the tuberculosis case.
Jennifer Martinez, who said her daughter would be tested for TB exposure on Tuesday, was one of the parents in attendance.
"I am just hoping she will be safe," she said.
Parents concerned about their child's health should contact their family doctor or Dallas County health officials.
Children who are not being tested at the high school can get a free tuberculosis exposure test at the Dallas County Health and Human Services clinic on 2377 North Stemmons Freeway in Dallas.
Tuberculosis is an airborne bacterial infection. It typically attacks the lungs but can also affect other organs, such as the brain, kidneys or spine. It can be fatal if not treated. Symptoms include flu-like conditions including coughing, fever and weight loss.
People are only at risk for contracting the infection 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. Casual contact such as a conversation, sports or a car ride should not lead to infection.
People with positive skin tests receive a chest X-ray. If the chest X-ray shows abnormalities on the lungs, it's possible the person has an active case of tuberculosis, and further testing is needed.
Dr. Jeffrey Kahn, the director of infectious diseases at Children's Medical Center, said tuberculosis is treated for six to nine months.
"You want to get tested early in the course of infection, and you want to make sure you get tested if you are exposed,” he said.
NBC 5's Lindsay Wilcox and Julie Fine contributed to this report.