Drug-resistant TB strains spreading in Asia-Pacific

MANILA, Philippines – Drug-resistant strains of tuberculosis are spreading largely unchecked in the Asia-Pacific because the region lacks adequate laboratory facilities to track them, the World Health Organization said.

“This is a serious situation,” WHO regional director Dr. Shigeru Omi said in a statement in Manila, where he is based. “We are worried this silent epidemic could set us back years. We could lose the gains made in recent years.”

Many Asia-Pacific countries lack the capacity to monitor and manage multi-drug resistant TB, or MDR-TB, resulting in the “vast majority of cases” spreading undetected and untreated, the statement said. Multi-drug resistant strains are TB bacteria that are immune to several types of medicines.

An untreated TB patient can infect 10 to 15 people a year just by coughing or sneezing. Infections can also spread among passengers on long-haul flights, WHO said.

“Without adequate laboratory support, we don’t know what drugs still work. We don’t even know the true scale of the problem,” Omi said.

To confirm infections, most developing countries rely almost exclusively on laboratory microscopes to identify the TB bacteria. Costly and complex culture methods, in which bacteria specimens are grown in a controlled environment to identify their specific strains, are used to detect drug resistance.

In 2006, only 600 of the estimated 150,000 MDR-TB cases in East Asia and the Pacific – less than one percent – were officially notified by a quality-assured laboratory.

Cambodia and the Philippines each have only three laboratories to diagnose MDR-TB by culture methods, although TB is a leading cause of death in both countries.

Mongolia and Papua New Guinea, both burdened by TB, each have only one such laboratory. China recently beefed up the number of laboratories able to diagnose MDR-TB, but most are not quality-assured.

WHO said surveys from 81 countries found that MDR-TB is spreading faster and is more widespread than previously thought.

The surveys showed the highest proportion of drug-resistant TB strains were in countries in the former Soviet Union and some provinces in China. It estimated that in 2006, one in 10 new MDR-TB cases occurred in China.

About five percent of new TB cases reported in South Korea, Mongolia, the Philippines and some areas of Vietnam were from drug-resistant strains, along with 20 percent of previously treated cases, the surveys found.

“If MDR-TB is mismanaged, an even more lethal form of TB may follow,” the WHO statement said.

A form of TB resistant to all of the most effective drugs has been reported in 45 countries, the statement said, without providing specifics.

This is “a grim threat to global public health because treatment options are either limited or nonexistent,” it said. – AP