TB strain may hamper global halt


The rise in the extensively drug resistant strain of tuberculosis, XDR-TB, threatens to derail efforts to bring the global epidemic of ordinary TB under control, the World Health Organization (WHO) said Thursday.

Launching the Global Tuberculosis Control report, WHO Director General Dr Margaret Chan said the good news was that the spread of TB had leveled off for the first time since the organization had declared it a public health emergency in 1993.

“However, if we are to meet the TB control target in the Millennium Development Goals, there is still a lot more work to be done,” she warned, referring to UN aims to halve the numbers of deaths by 2015 compared with 1990.

There were an estimated 8.7 million cases of the disease in 2005, killing an estimated 1.6 million people, 195,000 of them people living with HIV, Chan said.

While the Americas, South-East Asia and the Western pacific were on track to meet the target of the Global Plan to Stop TB, African, eastern Mediterranean and European regions were not, according to the WHO. However, the full extent of XDR-TB was still unknown and risked throwing all regions off course.

XDR-TB developed from MDR-TB, a multi-drug resistant strain immune to first line drugs treatment. The extensively drug-resistant XDR-TB resisted second line drugs too, meaning the death rate was much higher.

There were huge gaps in data, the WHO said, but Latvia had the highest known rate of XDR-TB.

“There is a one-in-five chance of being XDR-TB positive for people with MDR-TB already in Latvia. We very much suspect the situation is the same in the former Soviet Union,” said Dr Mario Raviglione, Director of Stop TB.

Drug resistance is caused by poorly administered treatment. If doctors or patients fail to follow the course of drugs prescribed precisely, a strain of TB can build up resistance.

More investment was needed for the research and development of new drugs, said Chan. While funding had increased dramatically to US$2 billion in 2007, there was still a US$1.1-billion shortfall if Global targets were to be achieved.