Leading health experts are calling for ?dramatic improvements in tuberculosis control? to prevent a potentially untreatable for of TB. The call comes at a two-day meeting in Johannesburg over concern about the spread of a deadly new form of TB known as XDR-TBHealth officials say it could result in a setback in treatment programs for HIV/AIDS, since the two diseases are so closely linked.

They?ve released a seven-point action plan, which includes more testing, diagnosis and treatment.

Dr. Paul Nunn of the World Health Organization is attending the Johannesburg meeting. He spoke to VOA English to Africa Service reporter Joe De Capua about XDR-TB.

?It is extreme drug resistant to the point where we?re talking about untreatable TB. So, the World Health Organization is particularly concerned that if these strains spread then we are going to be jerked back into the pre anti-biotic era, when in fact we do not have the drugs to treat patients. That is the potential of this epidemic,? he says.

But it goes beyond concern over the recent outbreak of XDR-TB in South Africa. Dr. Nunn says, ?Additional concern is brought about by the fact that we know from survey work we did recently that this strain or this kind of resistance is already present in most parts of the world. Mercifully, it?s only a tiny proportion of the patients that have been studied. But the big concern about the recent outbreak in South Africa is that when it?s become clear from here that when you mix XDR with HIV you can an explosive spread of XDR-TB. And therefore we are extremely concerned about the possibility of extension of the epidemic here.

Countries to the north of South Africa have the same sort of HIV levels but they don?t even have the capacity to carryout the diagnosis to measure drug resistance. And so obviously we?re concerned that there could even already be epidemics in those countries we are unaware of.?

At the recent 16th International AIDS Conference in Toronto, Dr. Nunn and others talked about TB being the ?Achilles Heel? of AIDS prevention programs.

?The expression was used by Dr. Kevin de Kock from the HIV department in WHO. What he was referring to was that there is a significant risk right now that investment into anti-retroviral treatment, particularly in Africa, stand to be wasted by XDR-TB killing off the patients that are actually on the anti-retroviral treatment?and therefore the call is any anti-retroviral program that?s in position to ensure that it also invest, or the government invest, or the development agencies invest also in control of drug resistant TB at the same time.?