Tuberculosis infections fall for first time, but why?

(CBS/AP) Tuberculosis is on the decline - for the first time ever.

A report issued by the World Health Organization estimates that 8.8 million people fell ill with TB last year, down from a peak of about 9 million in 2005. Officials said fewer people are now dying from the disease, though a third of cases worldwide probably go unreported.

What explains the decline? The WHO said increased availability of medical treatment was one factor.

The TB death rate is expected to fall by half by 2015 everywhere except Africa. India and China account for about 40 percent of the world's TB cases.

In recent years, health experts have warned of the rising threat of drug-resistant tuberculosis - a phenomenon that suggests many people with TB aren't getting proper treatment.

Last month, officials warned that drug-resistant TB was spreading fast in Europe and that there are few drugs left to treat it. In the report, officials said they didn't have enough data to know whether the global epidemic of drug-resistant TB is increasing, decreasing, or staying stable.

Last year, a rapid test for drug-resistant TB was unveiled in more than two dozen countries, allowing patients to be treated sooner and stopping the disease's spread.

"But the promise of testing more people must be matched with the commitment to treat all detected," Mario Raviglione, director of WHO's TB department, said in a statement. "It would be a scandal to leave diagnosed patients without treatment."

Tuberculosis is an infectious illness caused by a bacterium known as Mycobacterium tuberculosis. Though TB typically affects the lungs, any part of the body can be affected, including the kidney, spine, and brain. The disease spreads person when an infected person coughs, sneezes, speaks, laughs, or sings - all behaviors that can release into the air germs that another person then breathes in.

The CDC has more on tuberculosis.