How does tuberculosis (TB) spread?
Northern High School and Durham County health department officials are testing and monitoring more than 260 students and faculty at the school for exposure to tuberculosis.
Durham Public Schools is monitoring 266 people who may have been exposed to tuberculosis last week after a Northern student was diagnosed with an active case of the disease. The number includes students, faculty and staff, said William Sudderth, spokesperson for Durham Public Schools.
Tuberculosis is a respiratory disease that is very contagious but also very treatable, according to Durham County Health Department medical director Arlena Seña.
“It is a disease that anyone can get,” Seña said. “But it can easily be treated.”
Duke tuberculosis expert Tony Moody said the disease can take as long as a month for symptoms to emerge. But he said anybody with a persistent cough for more than two weeks who suffers from fevers and weight loss should seek medical attention.
The disease usually is transmitted by breathing air contaminated with the tuberculosis bacteria, according to Moody.
Wednesday’s announcement marked the second case of active tuberculosis diagnosed in the area during the past week. A student at UNC Chapel Hill was diagnosed with the disease last Friday.
It’s highly unlikely the cases are related unless the students crossed paths and spent a considerable amount of time together in an enclosed space or room. According to Moody, who studies the disease at the Duke Human Vaccine Institute, tuberculosis usually is spread by breathing the same air as an infected person.
“It sort of floats in the air and coughing is the way that we typically think about people spreading the bug,” Moody said. “Simply being in a room with someone who has tuberculosis can put you at risk. So it’s definitely something that can be transmitted fairly easily and certainly more easily transmitted in enclosed spaces.”
Moody went on to say that there was little danger of the disease being spread at Northern beyond those who were in immediate contact with the student last week. All those people are undergoing tests for the disease and being monitored by the Durham County health department, according to Seña.
A robocall from Northern principal Dan Filfort on Wednesday said students who have a class or ride the bus with the student affected will be tested. The student is not in school and is being treated at home.
Seña said removing the infected person from the environment for treatment was the first step in halting the spread of the disease. Because tuberculosis is an airborne disease, no major decontamination effort is required at Northern.
Seña said there is no required protocol for decontaminating surfaces for tuberculosis.
“The important thing is to isolate the person who has been infected with tuberculosis and then to treat the disease,” Seña said.
Durham County has averaged fewer than 10 cases a year since 2011. There were 11 Durham County cases in 2016, which was fifth in the state, according to North Carolina Health and Human Services statistics. Statewide, there were 219 cases in 53 counties in 2016 with the most coming in Wake (33), Mecklenburg (32), Guilford (19) and Robeson (14) counties. There were 47 counties that did not have a reported case of tuberculosis. Numbers for 2017 are not yet available.
Moody said tuberculosis usually occurs in areas of higher population and clusters in places where poverty and crowding are common. Tuberculosis usually is imported by people traveling from areas where the disease is more prevalent, according to Moody.
“Many other places in the world are more likely to see high cases of tuberculosis than we see here in the states,” Moody said. “But we do have a fair number of cases here in the U.S. It’s one of those diseases that can be passed from folks who have never left the United States. But also it is a disease that can be fairly easily brought in by other people.”
Treatment of tuberculosis can last up to nine months, according to Moody. Patients take a daily combination of drugs to fight the disease. Once it has been eradicated from the body, treatment ends. Unfortunately, the body does not develop an immune response to the disease and it is possible to become infected again.