10 Questions: TB Threat

286372 Making headlines this week is the case of a Georgia man suffering from a drug-resistant strain of tuberculosis now quarantined in Denver. Just how much of a risk does this virulent strain of TB pose to the general public? We asked Dr. William Schaffner, who heads the Department of Preventive Medicine at the Vanderbilt University School of Medicine, to help bring some perspective to the issue. He's the subject of this week's 10 Questions.

1. First, the simplest question—what is tuberculosis exactly, and why is it so dangerous?

Tuberculosis is a bacterial disease that affects the lungs most prominently. It is spread by exhaling infectious material that then is inhaled by close contacts. Spread usually requires prolonged, close contact in a confined area, such as a room (or an airplane). Without treatment, active tuberculosis can cause a slowly progressive disease that can result in death.

2. That unidentified TB patient, who is the first federal quarantine since 1963, is carrying a particularly drug-resistant strain of the disease. How could he have contracted it?

Where the patient acquired this multi-drug-resistant tuberculosis infection is not yet known – and is a question of great interest! Most such multi-drug resistant infections occur in the developing world.

3. The man took two long-distance cross-Atlantic flights, and four shorter flights within Europe. What is the risk for the people who sat near him—or on the same plane?

The risk is quite low. First, the patient likely was not very infectious to others. Second, previous similar investigations suggest that, if there is a risk, the persons seated in his immediate vicinity are the ones needing the most attention.

4. Are the people on the shorter flights in as much danger as the people on the longer flights?

The likelihood of transmission of tuberculosis increases with increasing time of exposure. That is why the longer flights are the major focus of the public health investigation.

5. Can this man be punished for ignoring the warnings of health officials not to go on these flights?

He can be admonished, but not punished. He has not violated any laws.

6. How is TB spread, exactly?

Bacteria in the lungs of infected patients are expelled through breathing, coughing, singing and even talking. They then can be inhaled by persons in close contact with the patient.

7. About how many people in the US have TB—and how preventable is it?

About 13,700 new cases of tuberculosis were diagnosed in the United States in 2006. The number of new cases has been diminishing steadily over the past decade. Early diagnosis and appropriate treatment of cases along with investigation of contacts are the foundation of the public health approach to tuberculosis prevention.

8. What is life like—what are the symptoms—if you have this kind of TB?

Tuberculosis produces progressive cough, shortness of breath, fever, lack of appetite, weight loss and progressive loss of strength. The disease used to be called "consumption" because one's vital energies were "consumed."

9. What is his life expectancy?

If this were the usual type of tuberculosis, we would expect a complete cure. However, these multi-drug-resistant strains are a challenge to treat successfully. Not knowing more clinical details, I'd not venture a prognosis at the moment.

10 What should the passengers on those planes be doing right now to either get diagnosed or get treated?

Concerned passengers ought to contact their local health departments along with the CDC website. The passengers will have their questions addressed and will be tested for tuberculosis exposure now and again in about 10-12 weeks.