WHO concerned by drug resistant strain of TB

The World Today - Thursday, 7 September , 2006
Reporter: Zoe Daniel

ELEANOR HALL: The World Health Organisation has released alarming findings about new strains of the disease tuberculosis, which it says are almost untreatable.In most Western countries TB is virtually non-existent but it's still highly prevalent in the third world. These virulent new strains have already infected people in the United States and Eastern Europe.And experts are meeting in South Africa to deal with a serious outbreak in the province of Kwa Zulu Natal, as Africa Correspondent Zoe Daniel reports.

ZOE DANIEL: It's feared that the Extreme Drug Resistant strain of TB was created by inappropriate use of TB medications. It's believed that TB resistance can be created by the use of drugs at the wrong dosage or for the wrong period of time.

Dr Paul Nunn from the World Health Organisation says the increasing prevalence of the drug resistant strain is a huge concern to health authorities.

PAUL NUNN: Well, the World Health Organisation is concerned because it's virtually or definitely untreatable. By definition this extreme drug resistance or XDR, as it's increasingly be called, is resistant to at least three of the six groups of second line drugs that are available. And by definition they're already resistant to the first line drugs. And so this means that any patient with XDR TB cannot get optimal treatment because we recommend that a patient with tuberculosis be treated with at least four drugs.

ZOE DANIEL: In South Africa an outbreak of drug resistant TB in Kwa Zulu Natal illustrates the extent of the problem. South Africa has the highest rate of HIV in the world, and tuberculosis is notorious for attacking the weakened immune systems of those who are HIV positive.However there was no treatment available when the drug resistant strain took hold, and the result for most was death.

PAUL NUNN: We carried out a survey that was published earlier this year showing the problem exists in about two per cent of cases globally. But what's most worrying is an outbreak recently reported from Kwa Zulu Natal showing that the XDR is there. That of the 53 patients that they looked at, 52 died within 210 days. So this is an extraordinarily high mortality rate. And clearly this is linked to the fact that all those tested were HIV infected as well. And this is the problem that we're really worried about. It's the spectre of extreme drug resistance fuelled by HIV in countries that don't really have the resources to address it right now.

ZOE DANIEL: At the moment TB causes about 1.7 million deaths per year around the world. But that's with the cocktail of drugs commonly used to treat it. Now resistance is showing up to the usual front line drugs and many of the so-called second line drugs that are used when the frontline drugs don't work.Dr Paul Nunn says part of the problem is that new drugs aren't coming onto the market because TB isn't present in most Western countries.

PAUL NUNN: During the 1980s and 1990s research into new anti-TB agents virtually disappeared in pharmaceutical companies because the TB problem was felt to be solved in the north and people did not realise the scale of the TB problem in developing countries at that time. And only in the last six or seven years has research really ramped up for new anti TB agents.The global alliance for anti TB drug development leading the fray, if you like, in New York funded largely by the Bill and Melinda Gates foundation. But clearly more investment in that area is required.

ZOE DANIEL: It's not yet clear how easily the drug resistant strain of TB is transmitted.

In Johannesburg, this is Zoe Daniel reporting for The World Today.