In 2005, 8.8 million people worldwide became infected with tuberculosis. That's a staggering number, but new cases of tuberculosis went up by just 70,000, which signals that the global TB epidemic is stabilizing.
At the same time, a new strain of drug-resistant TB has shown up in 35 countries, causing fresh concerns.
But authorities point to the 2005 figures as evidence of progress.
"The population of the world is growing faster than TB," said Mario Raviglione, coordinator of tuberculosis programs for the World Health Organization. "You have slightly more cases in total number, but in relation to the population there has been a peak."
Some countries are becoming more effective in detecting cases of the disease and making sure that the patient is cured. Curing patients helps to control the disease. More than 26 million were cured of TB in 2005, especially in Asia.
"If you take China, India, Indonesia, Philippines Cambodia, Vietnam — these are all countries that have put together effective programs which are reaching today quite a high case detection," Raviglione said. "So they detect many cases in their population and they cure the large majority of them, which is quite an advance over five or ten years ago."
The situation is much worse in Africa, if not in size, then in intensity. Twelve out of the 15 countries with the highest rate of TB are in Africa, where the epidemic of AIDS increases vulnerability to TB and undercuts the ability of health systems to respond.
Paul Nunn, director of the World Health Organization's program STOP TB, said the key with AIDS patients is to make sure they receive "a full course of treatment right to the end" of their lives.
"If that is not happening, you are letting the patient down and putting the community at risk," Nunn said.
TB patients are seldom checked to see if they also have HIV.
In not-so-poor South Africa, which has access to a second line of TB drugs when treatment fails, the failure to check for TB led to an outbreak of what is being called "extensively drug resistant" TB, or XDR.
With XDR, the first and second line drugs don't work. Nearly all of those initially identified with the disease — 52 out of 53 — died.
"Not only is the problem really severe, but in the area where it flashed up in the high HIV prevalence setting, it's still not under control," Nunn said.
More cases are being identified but mortality rates are down. Nunn says countries poorer than South Africa wouldn't be able to handle such an outbreak.
"There's a real risk that if it starts to travel to the north of South Africa it will travel into countries where the laboratory capacity to recognize that it's there doesn't exist," he said.
XDR is spreading in other parts of the world, too. It has been found in 35 countries, including the United States.
In the U.S., in the last five years, 17 cases of XDR have been identified. Kenneth Castro, the director of the Centers for Disease Control and Prevention's Division of Tuberculosis Elimination, said the majority of those cases were in people born outside the U.S.
"We need to make sure that we help reduce the number of people with tuberculosis, and by doing so reduce the likelihood of importation as well as the likelihood of us becoming infected as we travel and live overseas," Castro said.
That means we need to keep investing in controlling TB in other countries, Castro said.