"While the treatment success rate is fairly high at 85 percent, less than half (44 percent) of the cases are detected, resulting in a larger number of untreated carriers who spread the disease still further," said a USAID report.

A recent study of ICDDR,B said effective control of the disease burden is hampered by the fact that only 46 percent of TB cases are detected.

Tuberculosis (TB) is a major public health problem and a leading cause of adult mortality in Bangladesh. In 2006, World Health Organisation (WHO) ranked Bangladesh sixth among the world's 22 high-burden TB countries.

More than 319,000 new cases, including 143,000 sputum smear-positive (SS+) pulmonary TB cases and 70,000 TB-related deaths occur annually, mentioned the report.

In 1993, Bangladesh's National TB Control Programme (NTP) began implementing 'Directly Observed Therapy Short-Course (DOTS)'. After that, the case-detection rate under DOTS increased from 29.2 percent in 1993 to 61 percent in 2005 but so far failed in 100 percent detection.

The DOTS coverage also increased throughout the country -- from 90 percent in 1999 to 99 percent in 2004. The treatment success in TB, which was 81 percent in 1993, reached 89 percent in 2004.

"Yet many Bangladeshis are unaware of the fact that TB is curable and that treatment is available at public health facilities free of charge," said another study.

Control of TB depends upon the coordinated and effective implementation of programmes that combine both strategies to prevent TB and those to diagnose and treat it early.

ICDDR,B said it is early diagnosis and treatment that will prevent the spread of TB within households and among those coming into contact with active cases.

"The next challenge will be to identify persons infected with tuberculosis early, before they become sick. Earlier diagnosis means treatment can start earlier, thus preventing transmission to the next generation of TB victims," said ICDDR,B Executive Director David Sack.