Billionaire George Soros pledged $3 million Wednesday to fight a deadly strain of tuberculosis in Africa.

Since an outbreak of extensively drug-resistant tuberculosis, or XDR-TB was identified in South Africa last year, health experts have repeatedly issued dire warnings about the disease's spread across the continent, fuelled by the AIDS pandemic. But aside from a series of worldwide meetings, little concrete action has been taken.

Soros's Open Society Institute announced a $3 million grant to the non-profit organization Partners in Health and Brigham and Women's Hospital in Boston, Massachusetts. The donation will be used to design a model project of community-based XDR-TB treatment in Lesotho. Once treatment guidelines are developed, experts hope the program might be adopted in other poor countries.

Partners in Health has previously implemented community-based programs for drug-resistant TB in countries including Peru and Rwanda. "It is possible to treat highly resistant tuberculosis," said Dr. Paul Farmer, co-founder of Partners in Health, who disputed characterizations of the disease as "virtually untreatable." Farmer emphasized the need for HIV and TB treatment to be integrated.

"It's great that Soros has stepped forward, but what we really need is massive investments from governments," said Mark Harrington, executive director of the Treatment Action Group, a U.S.-based health advocacy group. "Governments have been embarrassed about the outbreak and terrified of not knowing what to do about it," he said, calling the XDR-TB problem "out of control."

Last September, the World Health Organization confirmed 53 XDR-TB cases in South Africa, of which 52 were fatal. Most of the patients were also HIV positive. To date, more than 300 cases have been identified, and at least 30 more are picked up each month. In a few weeks, WHO experts will finally begin helping South African authorities investigate the origins and spread of last year's outbreak. The World Health Organization estimates $650 million is needed to combat the XDR-TB problem annually.

XDR-TB exists worldwide, but it is of particular concern in Africa, where patients are often co-infected with HIV/AIDS, which essentially translates into a death sentence. XDR-TB is a variant of TB, an easily transmissible disease that is resistant to two of the second-line TB drugs, used as a last line of defense.

No XDR-TB cases have been found in neighbouring countries like Lesotho, Malawi or Zimbabwe, but experts suspect weak surveillance systems there are simply not picking them up. The disease has been identified in 28 countries worldwide, including all G8 countries.

The delayed response to XDR-TB, Harrington said, does not match the severity of the outbreak. "People think of TB as an old disease, and it's largely been ignored," he said. "But if they really understood how serious XDR-TB was, they would be scared out of their wits."