The growth of tuberculosis that is resistant to multiple drugs could cause a global crisis of untreatable disease, warns the World Health Organization.
Several "hot spots" - in India, Russia, Latvia, Estonia, the Dominican Republic, Argentina and the Ivory Coast - have so much drug-resistant TB that it threatens to overwhelm local health programs, said a study released Wednesday by the WHO and U.S. health officials.The study of 50,000 patients in 35 nations found that a third of the countries have at least some TB resistant to multiple drugs, ranging from 2 percent to 14 percent of the world total.
That number is low, but WHO said lethal tuberculosis could spread rapidly because only one in 10 patients gets medical care appropriate to curb drug resistance.
"This study shows definitively, and for the first time, what we most feared but could not previously prove: Our world again faces the specter of incurable tuberculosis," said Dr. Michael Iseman, TB chief at the National Jewish Medical and Research Center in Denver, who reviewed the study.
Drug-resistant TB "is on every continent, probably in every country," he said.
Tuberculosis is the world's top infectious killer. It is spread through coughing and sneezing and can be highly contagious - the average patient infects 10 to 20 people a year.
The World Health Organization announced last spring that TB's global spread had finally leveled off, but the new study looks specifically at killer drug-resistant forms.
Tuberculosis often can be cured with a combination of four drugs taken for six to eight months.
But many patients, especially in poor countries, stop taking the drugs when they feel better or run out of money, which allows the TB still in their bodies to mutate so that one or more medicines no longer work. This "acquired drug resistance" is entirely preventable with proper care, WHO said.
These people also can spread drug-resistant TB to new patients, a circumstance that gives patients what is called "primary drug resistance."
The WHO study found spots where resistance to a single drug is alarmingly high - it reached 100 percent of treated but not cured TB patients in Ivanovo Oblast, Russia, about 180 miles east of Moscow.
These people can be treated with other drugs, but they're in danger because the TB germ must make just one more mutation to become multidrug resistant - and lethal.
The study identified "hot zones" with multidrug-resistant TB at levels high enough to overwhelm local TB control programs:
- India's Delhi state, where 13 percent of all TB patients are multidrug resistant.
- Ivanovo Oblast, Russia, 7 percent.
- Latvia, 22 percent.
- Estonia, 12 percent.
- Dominican Republic, 9 percent.
- Argentina, 8 percent.
- Ivory Coast, 5 percent.