XDR-TB, or extensively drug-resistant tuberculosis, is a disease many Americans had never heard of before last week, but where I live and work in Rwanda, Multidrug Resistant TB (MDR-TB) is a persistent and growing feature of the public health landscape. While MDR-TB is resistant to at least the two most commonly used drugs, it can generally be treated and cured. XDR-TB is resistant to nearly all drugs and is considered virtually untreatable.
It should not shock Americans that this disease is making its way across the globe when every location is just a plane ride away. Yet the growth of XDR-TB has gone largely unnoticed in the US, where there have only 17 cases since 2000. In sub-Saharan Africa where roughly 25 million people are HIV positive, nearly half will develop TB. If treatment is not well administered, these cases will lead to new strains of resistant TB. There is a direct connection between the AIDS pandemic, TB, and the failure of health systems to appropriately diagnose and treat these diseases.
The good news is that the momentum to address this pandemic may be at hand. It's about time: about a year ago, the World Health Organization announced that 52 of 53 AIDS patients with XDR-TB died in South Africa. The international medical community has now acknowledged the looming problem, and, as witnessed last week, that acknowledgment occurred just when the threat to richer countries has appeared in the unlikely form of Andrew Speaker.
The recognized fact is that more funding and better research are needed now to stanch what may prove to be the next pandemic.
TB has plagued humankind since the 4th millennium BCE. While the disease only recently ceased to be a significant public health threat in the developed world, TB still claims 5,000 lives globally every day, more than SARS, Marburg, and avian flu ever have. Yet even on World TB Day, the disease rarely makes the headlines.
Lack of political and media attention has slowed scientific development. No new TB drug has been brought to market in the last 30 years (though the TB Alliance has promising candidates in the pipeline). A TB vaccine -- BCG -- is widely administered, but is ineffective in adults. Consequently, the disease has become endemic in poor countries where TB programs are underfunded. When a patient receives intermittent drug therapy or inadequate follow-up, or prematurely halts treatment, resistance can occur rapidly. Uneven treatment has resulted in drug resistant TB strains emerging globally. It's now time to address this crisis with the gravity and resources long accorded to AIDS and other diseases.
The first step is improving diagnosis and detection. In 1993, the World Health Organization recognized TB as a global health threat. Yet since then, the Geneva-based organization has continued to rely on an obsolete 125-year-old diagnostic tool -- microscopy. Over the past decade, rapid and accurate tests for TB have been developed but not widely approved. Why then do the WHO and many national TB programs keep outmoded methods as the cornerstone of their control strategies?
The simple reason is cost. Microscopy -- about 30 cents per patient -- is well-suited for most resource-limited settings. However, it cannot detect MDR-TB and XDR-TB. During the last five years, an advanced test, the line probe assay, has been proven effective. Though more expensive than microscopy -- cost estimates place the potential price around three dollars -- it can test many more people, faster, and reveals which treatment is best for their illness.
This test is desperately overdue. Of the 8.9 million new TB cases that emerged in 2004, barely half were reported at the time. An accurate, rapid diagnostic will cost money, but the result -- early treatment and cure -- will save billions of dollars and millions of lives in the long-term.
Treatment protocols also need reform. Right now, we settle for initially treating all TB the same way, shifting gears only after failure. When a person is found to be TB positive via microscopy in Rwanda, the patient receives drugs which may not work at all. It is only after several months have passed that further testing occurs and other drug regimens are applied. That's bad policy since it provides time for resistant strains of TB to spread.
A U.S. Senate committee is currently holding hearings on how health authorities handled Andrew Speaker's case. It is important that Congress and the world not miss the larger frame his case reveals: in an age of global jet travel, there is no such thing as an isolated case. TB anywhere is TB everywhere.
In the fight against XDR-TB, supporting worldwide efforts to fund improved diagnostics and treatment is the best investment we can make. Indeed, it is the only thing we can do.
Josh Ruxin, Assistant Clinical Professor of Public Health at Columbia University's Mailman School of Public Health, is Director of the Access Project in Rwanda.
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