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Alarm Bells Ring over Drug-resistant Strain of Tuberculosis

June 5, 2007 at 6:20 PM EDT
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MARGARET WARNER: Doctors reported today that the Atlanta lawyer who traveled overseas and back with a drug-resistant strain of tuberculosis does not appear to be highly contagious for now. But they made clear he’ll be in the hospital for at least a few months, and possibly much longer.

The case of Andrew Speaker is still sparking alarm about the risks of TB in an era of global travel. Tuberculosis remains a major health threat worldwide. Though U.S. cases hit an all-time low last year of just under 13,800, globally the picture is different. There were 8.8 million new cases worldwide in 2005, more than 7 million of them in Asia and sub-Saharan Africa; 1.6 million people died from it.

Public health authorities are particularly concerned about the rise of drug-resistant forms of the disease, like the strain of bacteria that infected Andrew Speaker. Today in Geneva, the World Health Organization said the Speaker case underscored the need for comprehensive action to detect, control, and treat TB, and to find new drugs.

Here to tell us more is NewsHour health correspondent Susan Dentzer.

So, Susan, when we refer to drug-resistant TB, what are we talking about?

SUSAN DENTZER, NewsHour Health Correspondent: Margaret, drug-resistant TB is TB that arises because of misuse of medication. Basically, when you’re diagnosed with tuberculosis, the typical plan of action is you go on several antibiotic drugs for six to nine months, and you have to stay on that treatment through that entire period.

If you don’t, certain organisms, bacteria, tuberculosis bacteria in your body that are drug-resistant, will flourish. That’s led to, in recent decades, drug-resistant TB. In addition, we’ve had multi-drug-resistant tuberculosis develop. This is TB that is resistant to two of the well-used, very powerful, first-line antibiotics, including the drug Rifampin.

And then, most recently, we’ve had the emergence of so-called extremely or extensively drug-resistant TB, XDR TB, which is resistant not only to those first-line drugs, also to one of a class of antibiotics called fluoroquinolones — some people may know the drug Cipro; that’s one of them — and then, finally, to the second line of drugs, including one of the injectable forms of that.

So if you’re resistant to all of those, you have extremely or extensively drug-resistant tuberculosis.

Combating drug-resistant strains

MARGARET WARNER: And so when the WHO says that this form of TB is on the rise, one of these drug-resistant strains, as a group, how much of a rise and where is it?

SUSAN DENTZER: It's rising fast. There's an estimated 25,000 to 30,000 cases worldwide. And against the backdrop of the numbers of cases we showed earlier, that's not that large, but it is rising quickly.

And what's most worrisome, in addition to the roughly half-a-million cases of multi-drug-resistant tuberculosis, is that the XDR form, the extremely drug resistant form, is highly fatal. It's fatal more than 70 percent of the time. And when outbreaks have occurred in groups of patients with HIV-AIDS, who already have very compromised immune systems, the fatality rate is almost 100 percent.

MARGARET WARNER: So what is the World Health Organization -- what did they propose today to do about this?

SUSAN DENTZER: Well, they renewed their call that has been in place now for at least a full year, if not beyond that. And, in fact, it's certainly -- going back to the enunciation of the U.N. Millennium Development goals in 2000, TB has been on the agenda.

And what they have been saying is that we need to spend about $56 billion between now and 2015 to stop TB, to roll back the number of cases, and particularly now to look at the so-called extremely drug-resistant TB forms, fighting it by virtue of developing new drugs, particularly new antibiotics that can be taken for much lesser durations of time.

That's what spread drug-resistant TB, is the fact you have to stay on it so long. So come up with new drugs that can be taken for much shorter periods of time, new diagnostic tools, in some cases that can take six weeks to 16 weeks to determine, through a culture, that one has infectious tuberculosis, so come up with faster diagnostics...

MARGARET WARNER: So that's one reason, for instance, that people fall off the regimen, if they're not being monitored?

SUSAN DENTZER: Exactly, and step up, throughout the developing world in particular, where TB is most pronounced, laboratory capacity to do these diagnostic tests, capacity to deliver so-called directly observed therapy, which is where somebody goes every day and watches to make sure that people who have TB are taking their medication. All of that the World Health Organization is calling for ramping up extensively to stop TB.

MARGARET WARNER: So what the WHO is saying, what you're saying is, you can't attack multi-drug-resistant TB without attacking TB? The one develops out of the other?

SUSAN DENTZER: You have to attack all TB; that's exactly right.

Andrew Speaker's case

MARGARET WARNER: Now, the case of Andrew Speaker, once he got it, he knew he had TB, and yet he was able to fly to Europe. Then, once he was told he had drug-resistant TB, he was able to fly within Europe back to Montreal and drive through the borders. We know that. Are there global rules against traveling with TB?

SUSAN DENTZER: Not rules against traveling per se, but there are guidelines, WHO guidelines, that actually were released last year about air travel in particular. And according to those guidelines, somebody with infectious TB should not be on an airplane before two full weeks of treatment. And, in fact, again according to the guidelines, the airlines should turn away, should not board passengers who have infectious TB.

So if those guidelines had been observed in this case, first of all, the airlines would have been notified that he had infectious TB, even though it's not particularly contagious as we've heard now, he would not have been allowed to board the flight.

MARGARET WARNER: So the bottom line, in terms of being exposed to it, is that having a goal, say, of eradicating TB in the United States is really kind of a fool's errand. I mean, there's no such thing. If there's TB in the world, every country is going to be exposed.

SUSAN DENTZER: Right. A number to keep in mind is one out of three people in the entire world have tuberculosis present in their body.

MARGARET WARNER: Carry the germ?

SUSAN DENTZER: They have the bacterium in their bodies. Now, only in 5 percent to 10 percent of people will that usually develop into active disease. So it's not common to have this move from the latent form to the active form, but it does happen.

But, again, as you say, the point is really to control all tuberculosis. And we know that that can be done, because this pattern of directly observed therapy has been shown to be extremely effective in the countries around the world where it's been done.

Treating drug-resistant TB

MARGARET WARNER: Now, when you talk about therapy, today there was a press conference with the doctor treating this Andrew Speaker. And it certainly sounded like his treatment is going to be particularly arduous. What is involved if someone gets a multi-drug-resistant strain or extremely drug-resistant strain?

SUSAN DENTZER: Well, for privacy reasons, they haven't expanded a lot on what Mr. Speaker is getting, but it seems to me a typical pattern.

MARGARET WARNER: But in general?

SUSAN DENTZER: He's on several antibiotics at this points, powerful antibiotics, they indicated today probably or at least possibly faces surgery, actually removing the infected portion of his lung. They'll make that decision in a few months when they get a couple more of these diagnostic tests back, but he could be in the hospital, as we said earlier, for months.

MARGARET WARNER: So if you're an ordinary person and you fly a lot, is there anything you can do to protect yourself against catching it?

SUSAN DENTZER: Well, the most important thing to remember, of course, is that relatively few cases proceed from the latent form to the active form. So that's good news.

MARGARET WARNER: As long as your immune system is strong?

SUSAN DENTZER: Exactly. There is one tuberculosis vaccine available. It's not recommended for people in the United States. So the best advice, first of all, is to -- if you're in the developing world, and you're around people who are coughing or sneezing a lot, take care against that, number one.

And, also, you can always go back when you return from a trip and get a tuberculin skin test to see whether you've been exposed to the disease. That will not show that you're positive until a couple of months after you've been exposed.

But most of all, if you are found to have TB, get treatment and stay compliant with it. That's the most important lesson that we have to take away from all of this.

MARGARET WARNER: Yes, to protect everyone else. Susan, thanks.

SUSAN DENTZER: Thanks, Margaret.