As a precaution, officials for the East Central Health District will re-examine students who returned negative skin tests for tuberculosis bacteria during the initial rounds of testing, according to Tammy Burdeaux, the district nursing and clinical director.
“It’s just to double-check,” she said. “The investigation is still ongoing.”
Three students have been diagnosed with tuberculosis and are out of school receiving treatment. The initial patient showed signs of the illness in October.
The health department tested 500 people who could have been exposed. Of that group, 75 tested positive for TB bacteria.
Testing positive for the bacteria is not a guarantee a patient will develop the disease.
According to 2010 data, the most recent available, 15 percent of people in Richmond County would test positive for the bacteria but 90 percent of that group would never develop the disease.
The three Butler students with TB all contracted a strain resistant to isoniazid, the most common drug used to treat the disease, Burdeaux said.
They are now being treated with other drugs.
According to the federal Centers for Disease Control and Prevention, 1.3 percent of the 10,528 cases of TB in 2011 were resistant to isoniazid and rifampin, the other drug used to combat the disease.