Disease experts have called for decisive leadership and more research funding to fend off the "very real" risk of an untreatable strain of tuberculosis (TB) emerging as more and more people develop resistance to existing drugs.
In a series of papers in the Lancet medical journal to mark World TB Day yesterday, they warned that health systems risked being overwhelmed by increasing numbers of drug-resistant TB patients.
Already, more than 30 per cent of newly-diagnosed patients in parts of eastern Europe and central Asia have multi-drug resistant (MDR) TB, a form of the disease which does not respond to the two most potent drugs - isoniazid and rifampin.
There were believed to be about 630,000 MDR cases out of some 12 million TB cases in 2011.
Extensively drug resistant (XDR) TB, thus far reported in 84 countries, does not respond to an even wider range of drugs.
"The widespread emergence of XDR tuberculosis could lead to virtually untreatable tuberculosis," wrote the authors of a study, led by Alimuddin Zumla, director of the Centre for Infectious Diseases and International Health at University College London Medical School.
"With ease of international travel and increased rates of MDR tuberculosis … the threat and range of the spread of untreatable tuberculosis is very real," they said.
TB was declared a global health emergency by the World Health Organisation (WHO) 20 years ago, but remains a leading cause of death by an infectious disease.
The United Nations agency says at least US$1.6 billion is needed annually to prevent the spread of the disease.
"The global economic crisis and reduced investments in health services threaten national tuberculosis programmes and the gains made in global tuberculosis control," they wrote.
Most needed are new drugs and better, quicker diagnostic tools.
In 2011, 8.7 million people fell ill with TB and 1.4 million died, said the WHO.
Over 95 per cent of TB deaths occur in low- and middle-income countries, and it is among the top three causes of death for women aged 15 to 44.
In 2010, there were about 10 million orphans who had lost their parents to TB. It is also a leading killer of people with HIV.
An airborne disease of the lungs, tuberculosis is usually treatable with a six-month course of antibiotics.
It is spread from person to person through the air and usually affects the lungs, but it can also affect other parts of the body such as the brain and kidneys.