NEWSWEEK: How does this new deadly strain of tuberculosis compare to normal TB?
Paul Nunn: XDR-TB is extremely drug-resistant TB and is unaffected by some of the frontline drugs traditionally used for TB. We began to notice that some TB patients were becoming more resistant over time. That is to say, a patient in 2004 that was drug resistant was, on average, resistant to more drugs than a patient who was diagnosed as resistant in 1995.
Where have you found incidents of the XDR strain?
It’s around the world including the U.S. and Africa. The biggest areas are Asia and the former Soviet Union, particularly the Baltic states.
TB is on the rise globally—8.9 million new cases were reported in 2004, the last year there is official data. What does the global landscape look like today?
If you divide the world up into the six regions like the World Health Organization does, then TB is going down or is stable in five out of those six. But it’s going up in Africa so much it’s making the entire world total go up. That is quite impressive for a region that contains only 11 percent of the world’s population.
Are you aware of any outbreaks or clusters of XDR-TB cases?
There was one outbreak in KwaZulu-Natal in South Africa his year where 52 of 53 patients died within on average 25 days. This was very concerning because it was associated with HIV and the mortality is extremely high. It would be extremely serious if XDR were being transmitted to people who have not had TB before, and this seems to be what happened in KwaZulu. It should send a warning message to all countries with similar rates of HIV that this is potential risk for them.
How worried should we be?
The World Health Organization is extremely concerned. XDR is a level of resistance, and it can occur in any of the genetic varieties of TB. About 2 percent of the TB cases are XDR. This could increase with HIV, which is really driving the epidemic.
Why are you so concerned about HIV?
If HIV comes along and disrupts the immune system then [a] latent [TB] infection can flair up. This would be horrendous for Africa. One major worry is people sick with HIV who may have intermittent fevers and coughs may not recognize XDR as the danger that it really is and delay in seeking out care.
How much does it cost to treat this new strain?
The cost of treating the new XDR for a single round of drugs can be $10,000. This is about 30 times more than for normal strains. The drugs are suboptimal because the strain is so resistant.
What can we do about the spread of XDR-TB?
XDR is caused by mistakes and problems with drug supply and treatment. It arises as a result of misuse or mishandling of drugs that have been given to the patient. This is what has to change. We need to perform quick and simple surveys in places we are expecting XDR to be found—say, big hospitals in big cities. We also need greater laboratory capacity. Most places in Africa don’t have this. We also need to beef up capacity of clinicians who manage the disease and the public-health managers who have to control the process. We also urgently need new drugs to combat XDR.
What are the symptoms of XDR-TB?
They are the same as tuberculosis: coughing, a fever, maybe coughing up blood.
How does XDR spread?
It spreads like regular TB does, by droplets. Anyone who coughs, sneezes, sings or shouts into the air produces droplets that float in the air for a while and gradually sink and can be breathed in by anybody in the vicinity.
Is this exacerbated in confined places like airplanes?
Not really. We do recommend to airlines that if someone has a cough for a long duration then they should not travel.
What advice do you have for patients?
For any patient infected with HIV, at the first signs of TB infections, go get screened. If you are HIV-positive and if you have TB and it is untreated or treated with the wrong drug, you can die in a matter of weeks.
