'Silent' TB Epidemic Spreads Amid Lack of Laboratory Facilities

2008-03-24 09:06 600

MANILA, March 24 /Xinhua-PRNewswire/ -- Inadequate laboratory facilities in Asia and the Pacific are fuelling the spread of drug-resistant strains of tuberculosis (TB), the World Health Organization (WHO) said today.

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Many countries lack basic laboratory capacity to monitor and manage multidrug-resistant TB (MDR-TB), WHO said, with the result that the vast majority of cases go undetected and untreated.

Less than 1% of MDR-TB cases are confirmed by a laboratory and officially reported in the region. In 2006, only 600 of the estimated 150 000 MDR-TB cases in WHO’s Western Pacific Region—which covers East Asia and the Pacific—were officially notified by a quality-assured laboratory.

Undetected and untreated, a TB patient can infect 10 to 15 people a year—simply by coughing or sneezing. Infection can spread on long-haul flights. Last year, American health authorities followed up 100 such cases.

The spread of MDR-TB is every TB programme's nightmare. One case can take up to two years to treat with drugs that have serious side effects and cost 100 times more than the regular regimen of drugs.

“This is a serious situation. Outbreaks of multidrug-resistant TB are going unnoticed constantly,” said Dr Shigeru Omi, WHO's Regional Director for the Western Pacific. “We are worried this silent epidemic could set us back years. We could lose the gains made in recent years.”

In a message for World Stop TB Day on March 24, he added: “Without adequate laboratory support, we don’t know what drugs still work. We don’t even know the true scale of the problem.”

Most developing countries rely almost exclusively on the 125-year-old microscopy method to confirm infectious TB. But drug resistance must be detected with “culture methods”. The costs and complexities of these methods hamper widespread use.

Record rise of MDR-TB

A recent WHO report based on surveys from 81 countries found MDR-TB is now spreading faster and is more widespread than previously believed. Nearly half a million MDR-TB cases are estimated to occur globally.

In addition to countries of the former Soviet Union, provinces in China have reported the highest proportion of resistance, surveys show. WHO estimates that in 2006, 1 in 10 new MDR-TB cases occurred in China, despite considerable efforts and investment to improve TB control.

Other countries in the region also report high drug resistance. Roughly 5% of new TB cases in the Republic of Korea, Mongolia, the Philippines and possibly in some areas in Viet Nam are multidrug-resistant. MDR-TB among previously treated cases is even higher, even reaching 20%.

If MDR-TB is mismanaged, an even more lethal form of TB may follow. Extensively drug-resistant TB (XDR-TB), a form of TB resistant to all the most effective drugs, has now been reported in 45 countries worldwide. XDR-TB is a grim threat to global public health because treatment options are either limited or non-existent. A 2005 outbreak in South Africa killed 52 of 53 HIV patients.

Quality laboratories lacking

Although culture methods are used routinely in developed countries, there are only a few laboratories in some countries in the region able to conduct such tests.

Cambodia and the Philippines, for example, have only three laboratories each able to diagnose MDR-TB by culture methods, although TB is a leading cause of death in both countries. Mongolia and Papua New Guinea, countries with a high TB burden, only have one laboratory doing culture. China has recently beefed up the number of laboratories able to diagnose MDR-TB, but most of the laboratories are not quality-assured.

Countries need to do more than upgrade laboratories. Dr Pieter Van Maaren, WHO Regional Adviser for Stop TB and Leprosy Elimination, said that laboratories have long been neglected, suffering from a shortage of funds, trained personnel and quality assurance systems.

Source: World Health Organization