Lethal TB Quarantine: Are Others at Risk?

Passengers and crew on two recent transatlantic flights may have been exposed to a rare and unusually drug-resistant strain of tuberculosis by an unidentified man who is now under federal quarantine. Officials at the Centers for Disease Control (CDC) say it's been more than 40 years since a similar isolation order was given.

In an effort to contain the spread of this often-lethal form of the disease known as XDR TB, health authorities are asking passengers who traveled on either flight (Air France Flight 385 from Atlanta to Paris on May 13 and Czech Air Flight 0104 from Prague to Montreal on May 24). to come forward for testing. Tuberculosis is an airborne bacterial infection that usually affects the lungs and is usually spread by people in close quarters. While rates of the disease are fairly low in the United States (fewer than 14,000 cases were reported last year), it is a leading health problem worldwide—particularly for those with compromised immune systems. There were 1.6 million TB deaths in 2005 according to the World Health Organization.

NEWSWEEK's Eve Conant spoke with Dr. Carl Nathan, chairman of the Department of Microbiology and Immunology at Weill Cornell Medical College and a leading tuberculosis expert, about how the disease spreads and why lengthy quarantines may be the medical community's best weapon against the most deadly strains. Excerpts:

NEWSWEEK: Most of us have heard of TB, but not of XDR-TB. What is that and how does one get it?
Carl Nathan:
TB is usually a treatable disease, but you're often looking at more than six months of treatment with multiple drugs, which unfortunately is hard for a lot of people to manage. In many parts of the world people also may not have as much access to medicine and so they interrupt treatment. TB can be resistant to one or more drugs, the two most important are isoniazid and rifampin. If your body is resistant to these two drugs it's called multidrug resistant TB, or MDR-TB. XDR-TB comes when a person is resistant to those drugs, to another important group of drugs called fluoroquinolones, and to all injectable drugs. So there's very little left to do for them. This is a very serious problem.

What are a person's chances of surviving XDR-TB?
For someone with XRD-TB, the full-blown disease, the fatality rate is very high as there is very little to be done about it. It's potentially untreatable and a great public health concern. There are an estimated 450,000 cases per year of MDR-TB with a fatality rate of 67 percent. This resembles the situation before there were any drugs for TB, leading up to 1950 when there was a 50 percent fatality rate. This is made even worse by the fact that so many people with MDR-TB are also HIV-positive, making it even more lethal. XDR-TB is the worst of all, it's already been reported in 17 countries and is estimated to be 10 percent of all MDR cases. This means there are 45,000 people with XDR-TB worldwide. The fatality rate isn't exactly clear yet, but the Lancet reported that in a South African population of 53 people with XDR-TB, 52 died. The median survival time after diagnosis was 16 days.

Are airline passengers particularly vulnerable?
The risk factor really comes from sharing air. If you look at an airplane, like the case now, you'll find that the infection rate of people who are potentially exposed is actually quite low. There was a similar case in 1996 reported in the New England Journal of Medicine, but the person in question had MDR-TB. It was found that a traveler with MDR-TB seemed more likely to infect a person if on a flight more than 8.5 hours, and only those people nearest to them. So infection didn't come through the recirculated air, but through direct exchange. There was a 6 percent infectivity rate among passengers. That's encouraging, that's not everyone on the plane.

TB rates in the United States are very low.
But that should be small comfort. Worldwide it is still the leading cause of death from bacterial infection, and it's also the leading cause of death worldwide among people who are HIV-positive. The U.S. may have low rates, but what about tourists, travelers—immigrants? Any of those people could represent a source of infection even among people who haven't traveled. Americans should be concerned, not just for other people worldwide, but also out of self-interest. There are no oceans or borders when it comes to infectious diseases. Everyone else's infection problems are our problems.

Given the low infection rates in the United States, is enough being done to fight TB?
Not at all. There is more being done than before, but what we really need is more research and development toward a vaccine or toward chemotherapy or antibiotics to treat it.

Aside from this case, there is also the case of Robert Daniels, who earlier this year was effectively quarantined in Arizona for having drug-resistant TB he picked up while working in Russia. Is quarantine the only option?
If someone is at risk of an untreatable and potentially fatal disease that can infect others, then yes. You must quarantine them, especially if you can't treat that person.

But if you can't treat them, what do you do with them in quarantine?
You wait until the disease runs its course. It could take years, but if you look at that recent XDR-TB outbreak in South Africa, you'll see that the time to death is very quick.

You mean in most of these rare cases you just wait for the person to die quickly or heal slowly?
Exactly. It is possible in some cases to operate. If there are a limited number of lesions on the lung, then sometimes surgery can remove that part of the lung that is infected. TB is communicated by coughing out infectious material from broken-down lung tissue, so surgically removing that part of the lung might work. There may also be experimental drugs or new combinations of drugs that can be tried.

What can airlines do?
You can't screen everyone, but after the fact, if the flight is more than 8 hours, it's recommended that the airline contact passengers who were sitting near the infected person. But again, that is after the fact.