An article published Online First and in a future edition of The Lancet, documented by Dr Abigail Wright, Dr Dennis Falzon and colleagues from the World Health Organization in Switzerland, reports that in the fourth round of data from the Global Projection on Anti-Tuberculosis Drug Resistance, greater part of the multi-drug resistant (MDR) tuberculosis (TB) weight falls in China and former Soviet States rather than in high income countries.

Between 2002 and 2007, researchers using standardized results arrived at a consistent gathering of outcomes collected and evaluated from within 90,000 patients in 83 countries. Information for HIV status and cases of extensively-drug resistant (XDR) TB was also collected when possible.

From the study, researchers discovered that for new cases of TB, the average frequency of resistance to any drug was one in nine cases equaling 11 percent. In highly developed countries, the frequency of MDR-TB among new TB cases was very low from less than 1 percent in countries like UK, Netherlands and New Zealand, to between 1-2 percent in countries like France and Germany respectively. On the other hand, however, the frequency of MDR-TB in two provinces of China was up to 7 percent, and between 7 percent and 22 percent in nine countries of the former Soviet Union, including 19 percent in Moldova, and 22 percent in Baku, Azerbaijan*.

Trend investigations demonstrate that, between 1994 and 2007, the incidence of MDR in new TB cases increased significantly in South Korea (1.6 percent in 1994 to 2.7 percent in 2004) and in Tomsk Oblast (6.5 percent in 1999 to 15.0 percent in 2005) and Orel Oblast (2.6 percent in 2002 to 8.8 percent in 2006), Russia. It was stable in Estonia and Latvia (13.3 percent and 10.8 percent respectively in 2005). The occurrence of MDR-TB in all TB cases decreased in Hong Kong (2.6 percent in 1996 to 0.9 percent in 2005) and the USA (2.4 percent in 1994 to 1.2 percent in 2005). Analyzing the data on a regional and income basis, in high-income countries prevalence of MDR among all TB cases was 1 percent. Eastern Europe had the the highest rate of incidence (19 percent), Latin America 3 percent, Africa 2 percent, and Southeast Asia 4 percent. XDR-TB cases were reported by 37 countries having representative surveillance information. Five former Soviet states (Azerbaijan [Baku], Estonia, Latvia, Lithuania, and Russian Federation [Tomsk]) each reported 25 cases or more, with prevalence of XDR-TB among the total of MDR-TB cases ranging from 7 to 24 percent in these countries.

The researchers write: "Data from our global survey show regional and national variation in the magnitude and trends in drug-resistant TB. Countries of the former Soviet Union, followed by some provinces of China, reported the highest prevalence of resistance, while the eastern Mediterranean region and southeast Asia reported prevalence of resistance on par with estimated global averages. The data presented here show that of the half a million MDR-TB cases estimated to have emerged in 2006, 50% were in India and China alone, and 27 countries account for 86% of the world's MDR-TB burden. Countries in the Americas, western and central Europe, and Africa reported the lowest prevalences of MDR-TB." They point out: "The countries of the former Soviet Union are facing a serious and widespread epidemic with the highest prevalence of MDR-TB ever reported in 13 years of global data collection."

In conclusion, the authors debate on the priorities for countries to carry out the new Stop TB Strategy. It was first introduced in 2006 and expands upon the direct observation of short-course treatment (DOTS) approach. They write: "Currently, the world is far behind reaching the targets for MDR-tuberculosis diagnosis and management set out in the second Global Plan to Stop TB 2006-2015. Until drug susceptibility testing is implemented routinely for tuberculosis cases as the standard for diagnosis and surveillance, survey mechanisms will continue to be crucial for the determination of trends and the documentation of emergence of further resistance to second-line drugs."

In a supplementary remark, Dr Martien W Borgdorff, Academic Medical Centre, University of Amsterdam, Netherlands, and Dr Peter M Small, Bill and Melinda Gates Foundation, USA, and Institute for Systems Biology, USA, consider various potential developments concerning rapid diagnosis tests, as well as TB drugs with innovative mechanisms of action.

They write in conclusion: "Worldwide, there are early signs of action. A group of countries, which together have nearly 45% of the world's TB and high rates of drug resistance, are leading new control efforts. In March, Brazil hosted the Stop TB Partners' Forum in Rio de Janeiro, and China convened a meeting of countries most affected by MDR-TB. India has set an objective for universal access to MDR-TB treatment and South Africa is now home to crucial clinical research trials of vaccines, drugs and diagnostics. These commitments could herald a new framework in global health in which endemic countries with emerging economies stimulate a global response."

* In some cases, information was provided for whole countries and in others cases it was provided for particular cities or regions. See full paper/appendix.

"Epidemiology of antituberculosis drug resistance 2002-07: an updated analysis of the Global Project on Anti-Tuberculosis Drug Resistance Surveillance"
Dr Abigail Wright MPH , Matteo Zignol MD, Armand Van Deun MD, Dennis Falzon MD, Sabine Ruesch Gerdes PhD, Prof Knut Feldman MD, Sven Hoffner PhD, Prof Francis Drobniewski MD, Lucia Barrera MD, Dick van Soolingen PhD, Prof Fadila Boulabhal PhD, CN Paramasivan PhD, Kai Man Kam MD, Satoshi Mitarai MD, Paul Nunn MD, Mario Raviglione MD, for the Global Project on Anti-Tuberculosis Drug Resistance Surveillance.
The Lancet, Early Online Publication, 16 April 2009 doi: 10.1016/S0140-6736(09)60331-7
thelancet
Stephanie Brunner (B.A.)

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