Tuberculosis Spreading in Surprising Ways
The U.S. has a national TB elimination program and every state has officials charged with monitoring and controlling any outbreaks. TB was once thought to be nearly eradicated here, but there was a significant resurgence of the disease from 1985 to 1992, when the number of cases grew by 20%. Progress has been made, however. In 1953, there were 85,000 new cases of TB, compared to 17,000 in 1999. At the same time, more cases are being discovered that are resistant to drugs, which makes the disease more difficult to do away with.
The waste facility worker was one of three employees in the same processing plant who all developed TB during the period from May to September 1997. State and federal authorities were called in to investigate the source of the outbreak and to take steps to stop the infection from spreading throughout the community.
Johnson and her colleagues interviewed all three workers and their friends and family members, reviewed their medical records and conducted TB tests on them. Some were found to have a positive skin test, indicating they had been exposed to TB, but none had an active case of infection.
They also conducted sophisticated genetic tests on the type of TB each of the workers had, and found that one was infected with a particularly rare strain that is resistant to drugs that usually kill TB. Then, after checking the type with all the laboratories that sent their used TB tests to this facility for waste processing, the researchers were able to match this worker's TB with that of a person with the same type who was seen at one of the labs.
The other workers may also have contracted TB from the waste they processed, but because they had more common forms of the disease, this could not be proven, Johnson says.
All of the workers were treated with antibiotics. In addition, the waste facility was required to implement additional safeguards to better protect its workers. The investigation for the source of the outbreak had revealed that the workers had been regularly exposed to any number of infections. Equipment was broken, workers often failed to wear the proper protective gear, and they did not shower or decontaminate themselves after exposures, according Johnson.