WHO expert warns of ‘virtually untreatable’ TB

The World Health Organisation (WHO) has called for urgent action on a deadly form of drug-resistant tuberculosis that, it says, is threatening to spread globally.

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By  Joanne Bladd Published  October 11, 2006

The World Health Organisation (WHO) has called for urgent action on a deadly form of drug-resistant tuberculosis that, it says, is threatening to spread globally. Extreme drug resistant TB (XDR TB), defined as strains resistant to front-line and three or more second-line TB drugs, has been identified in the US, Eastern Europe and Africa and is “virtually untreatable”, according to Dr Paul Dunn, coordinator of the WHO’s Stop TB department. “XDR is very serious – we are potentially getting close to a bacteria that we have no tools, no weapons against,” he said. It is thought that poor prescribing practices, low drug quality (or erratic supply) and poor compliance with TB treatment are behind the increase in cases. A recent survey of 18,000 TB samples by the US-based Centres for Disease Control and the WHO found 20% of them were multi-drug resistant, and a further 2% extreme drug resistant. Similar studies in South Korea and Latvia revealed the number of multi-drug resistant TB cases that met the criteria for XDR TB to be 15% and 19% respectively. “For the world as a whole, it is potentially extremely worrying that this kind of resistance is appearing,” Dunn said. The rising incidence of XDR TB, particularly in Africa, is potentially devastating, when allied with the prevalence of HIV. The combination promotes particularly rapid spread of the disease within hospital settings and the community. As a separate study, published in the British Medical Journal reported, among 536 cases of tuberculosis confirmed at a rural hospital in South Africa earlier this year, 41% were multi-drug resistant and of those, 24% met the definition of XDR TB. All patients in this outbreak who were tested were HIV positive and 52 of the 53 died after an average of 25 days. The study’s author Dr Stephen Lawn, a senior lecturer in infectious and tropical diseases at the University of Cape Town, South Africa, writes that several responses to the issue are required including urgent assessment of the scale of the problem and an increase in laboratory capacity. “Detection rates for cases of tuberculosis need to be improved, highlighting the need for a new diagnostic test,” he said. “Technologies that can determine the presence of drug-resistance at the point of care are needed as are new drug treatments.” Commenting on the study, Dunn said, “For the people in southern Africa, it is a likely death sentence. We need to make sure we do the basics properly, in other words ensuring and, where necessary supervising, that the patient takes every pill for the course of the treatment.” Last month, experts convened in South Africa to discuss the problem. WHO-led strategies are expected to be announced in the next month.

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