Drug-resistant TB spreading faster than feared

LONDON — Drug-resistant tuberculosis is spreading even faster than medical experts had feared, the World Health Organization warned in report issued Tuesday.

The rate of TB patients infected with the drug-resistant strain topped 20 percent in some countries, the highest ever recorded, the U.N. agency said.

"Ten years ago, it would have been unthinkable to see rates like this," said Dr. Mario Raviglione, director of WHO's "Stop TB" department. "This demonstrates what happens when you keep making mistakes in TB treatment."

Though the report is the largest survey of drug-resistant TB, based on information collected between 2002 and 2006, there are still major gaps: Data were only available from about half of the world's countries.

In Africa, where experts are particularly worried about a lethal collision between TB and AIDS, only six countries provided information.

"We really don't know what the situation is in Africa," Raviglione said. "If multidrug-resistant TB has penetrated Africa and coincides with AIDS, there's bound to be a disaster."

Raviglione said it was likely that patients — and even entire outbreaks of drug-resistant TB — were being missed.

Experts also worry about the spread of XDR-TB, or extensively drug-resistant TB, a strain virtually untreatable in poor countries. When an XDR-TB outbreak was identified in AIDS patients in South Africa in 2006, it killed nearly every patient within weeks. WHO's report said XDR-TB has now been found in 45 countries.

Globally, there are about 500,000 new cases of drug-resistant TB every year, about 5 percent of the 9 million new TB cases. In the United States, 1.2 percent of TB cases were multi-drug resistant. Of those, 1.9 percent were extensively drug-resistant.

The highest rates of drug-resistant TB were in eastern Europe. Nearly a quarter of all TB cases in Baku, Azerbaijan, were drug-resistant, followed by about 20 percent in Moldova and 16 percent in Donetsk, Ukraine, WHO said.

High rates of drug-resistant TB were also found in China and India, the world's two most populous nations that together are home to half the world's cases.

Drug-resistant TB arises when primary TB treatment is poor. Countries with strong treatment programs, like the U.S. and other Western nations, should theoretically have very little drug-resistant TB.

That is not the case in China, however, where the government says 94 percent of TB patients complete their first TB treatment.