Thailand: Early diagnosis is key to controlling MDR-TB
Dr Manoon Leechawengwong, is the chairman of the Drug Resistant TB Research Fund at Bangkok’s Siriraj Foundation and is also the Immediate Past President of Thai AIDS Society-- His foundation is under the patronage of the King’s sister--The Royal Highness Princess Galyani Vadhana Krom Luang Naradhiwas Rajanagarindra. He recently spoke to CNS in Bangkok about the rising problem of multi drug resistant TB (MDR-TB) in Thailand. Dr Manoon believes that drug susceptibility testing (DST) is the first crucial step in managing drug-resistant TB. It is a necessity, and not a luxury, to do culture testing for all TB patients, to help guide the physicians to select the optimal anti-TB medicines. However, a major barrier to controlling MDR-TB in Thailand (and elsewhere too) is the lack of cheap, rapid and accurate diagnostic test methods. Dr Manoon’s hospital has a cheap technique to detect MDR-TB at the cost of USD 4-5, provided AFB (Acid Fast Bacilli) is smear positive.
Dr Manoon informed that, “In Thailand there are annually approximately 60,000 identified cases of TB who need this test. We have done more than 30,000 cases in our lab in 10 years, and found more than 1000 cases of MDR-TB and 60 cases of extensively drug-resistant TB (XDR-TB). It is in the best interest of all concerned citizens to help Thailand fight this difficult-to-treat form of TB. That is why our Drug-Resistant Tuberculosis Research Fund performs DST free of charge for all TB smear positive patients from government hospitals in Thailand. In future, with adequate funding, this free testing may be offered to private hospitals too in Thailand and even to medical facilities of our neighbouring countries. Drug-Resistant Tuberculosis Research Fund has succeeded in mobilizing more than USD 1 million from private donors since 2001 serving patients in need of DST for drug-resistant TB.”
Dr Manoon said that it is bad practice to add a single drug to the failing four drug first-line anti-TB regimen, as had happened in the case of a sputum smear positive patient, whose condition worsened even after four months of treatment for drug susceptible TB (DS-TB) at a government hospital. The treating physician then added one more medicine to the failing standard four-drug first-line regimen the patient was receiving but with no success. It was at this stage that the patient was referred to Dr Manoon. When Dr Manoon conducted DST he found that this patient was resistant to all the four first-line anti-TB medicines: rifampicin, isoniazid, ethambutol and pyrazinamide. So he shifted the patient to second-line medicines and his condition improved immediately. Had this patient continued his previous treatment he might have developed resistance to second-line anti-TB drugs too and got XDR-TB.
According to Dr Manoon, “The Rapid TB Laboratory Diagnosis Service (Fast Track) involves: microscopic examination; direct detection of genetic material; detection and isolation with an automatic culture system; species identification by gene detection; anti- mycobacterial susceptibility test. Results are reported within one month compared to 2-4 months using conventional methods. The advantage of the TB Fast Track Services are that it (i) provides a rapid diagnosis and information about the susceptibility of the etiologic mycobacteria, (ii) helps to reduce the transmission rate by choosing an appropriate regimen for the patient, (iii) collects and analyzes all data concerning drug-resistant TB in Thailand which is useful for all physicians to use as a tool in the prevention and treatment of the disease.”
Thailand had recorded cases of MDR-TB and XDR-TB since late 1990s, and drug-resistance had been around much before 2006 when WHO first recognized the problem of MDR-TB and XDR-TB. In June 2007, Dr Manoon’s lab had diagnosed 13 cases of XDR-TB which was perhaps just the tip of the iceberg of DS TB. Currently, Thailand gets 2000 cases of MDR-TB in government public hospitals every year and 5% of them are likely to be XDR-TB. The Government of Thailand financially supports MDR-TB treatment but in the private sector a MDR-TB patient might spend around THB 200,000. In Dr Manoon’s clinical practice, MDR-TB treatment success rate is between 70%-80%.
Dr Manoon said that, “We need volunteers to help strengthen TB programme at local level. Masks help prevent at least 60% of TB spread – patients only need to change when masks get wet. But Thai people do not like to wear masks because of the fear that people might discover that they are ill. They should wear masks and not keep coughing. Non-Thai migrants should receive more focus as they are part of the unreached populations for healthcare services.”
It would be worthwhile here to mention here the situation in Thailand’s neighbor Myanmar which contributes to this migrant population in a big way with over one million registered Burmese migrant workers and a greater number of unregistered ones in Thailand. Dr Philippe Clevenberg, Country Director, at the International Union Against TB and Lung Disease, Myanmar, informed that, “Myanmar is in a phase of economic growth and it may influence TB and HIV responses in the country. There is an increase in internal migration from rural areas in the pursuit of better economic prospects. Such a migration trend may put people more at risk of TB and HIV if living conditions and other socio-economic determinants are not attended to. At the same time, improvement in financial condition is one of the most effective ways to curb the TB epidemic. A tuberculosis survey done in Myanmar in 2009-2010 found that prevalence of TB was double of the estimated number of 600,000 – 700,000 active TB cases per year. According to the national TB programme in Myanmar 10% of these TB patients are also co infected with HIV. In some places where TB-HIV collaborative activities are getting implemented TB-HIV co-infection is found to be as high as 20% indicating that TB-HIV co-infection is even a bigger problem. There is an urgent need to accelerate case-finding activities in Myanmar though improved access to diagnostic services, improved TB screening tools and algorithms, and to expand partnerships for TB control.”
As I write this piece, I am happy to hear the news that the United States President’s Emergency Plan for AIDS Relief (PEPFAR) has just announced an additional $11 million to provide up to 150 Xpert® MTB/RIF instruments and 450,000 test cartridges in 14 high-burden countries across sub-Saharan Africa and in Myanmar. The Cepheid Xpert® MTB/RIF can detect Mycobacterium tuberculosis DNA and mutations associated with rifampicin resistance directly from sputum specimens in less than 2 hours. The ability of the Xpert assay to detect smear-negative TB provides a significant advantage over smear microscopy, especially for persons with TB who are also HIV-infected. It is hoped that this would go a long way in addressing the problems of DS and MDR –TB by way of early diagnosis and hence treatment. The ripple effect of this might percolate to neighbouring Thailand too which is also committed to diagnose early and treat successfully all forms of tuberculosis.