Tuberculosis or TB remains one of the most deadliest communicable diseases in the world; in 2013, it caused 1.5 million deaths. An estimated 9 million people developed TB that year, of which 4,80,000 cases were resistant to first-line drugs.
Effective new tools are essential for curbing the epidemic – notably to reach the 3 million people each year who do not receive a diagnosis — and informing appropriate treatment.
Now, a new report from Foundation for Innovative New Diagnostics (FIND), McGill International TB Centre and UNITAID has presented a snapshot of the TB diagnostics landscape. The report has pointed out that Brazil, China, India and South Africa – which together account for nearly half of all TB cases – offer tremendous opportunities for new diagnostics.
The fourth edition of the report — TB – Diagnostics technology and market landscape — released recently, noted key features of each market. For instance, the vast majority of TB diagnostics in Brazil and South Africa takes place in the public sector, while India has a significant private sector. In China, most people with presumptive TB seek diagnosis in hospitals.
Dr Madhukar Pai, professor of epidemiology at the McGill University, told The Indian Express that a significant volume of TB testing is done in these four countries, where over 88 million tests are performed. China has the highest number of diagnostic tests (44.2 million), India has the second highest (32.8 million) followed by South Africa (9.2 million) and then Brazil (2.4 million).
Although many countries still rely on basic tools such as smear microscopy, new diagnostics is changing the landscape. The report — put together by David Boyle (PATH, Seattle) and Madhukar Pai (McGill University, Montreal), with technical inputs from FIND and UNITAID — reviews current and potential future technologies to improve access to better TB diagnostics. Data for this landscape report was derived from contact with over 100 technology developers working within the TB diagnostics market, ranging from established multinational diagnostic companies to start-ups and academic groups.
The predominant diagnostic test in these countries is sputum smear microscopy. Diagnostics are also necessary to detect latent TB infection (LTBI), which can be treated to prevent progression to active disease.
The report points out that although rapid drug susceptibility tests are available and endorsed by the World Health Organisation, they are still not widely implemented in many low-income countries. This results in detection of less than one in two cases of multidrug-resistant (MDR) TB. Patients often receive MDR TB screening only when they fail to respond to standard first-line TB treatment, or have recurrence of TB; this contributes to morbidity, mortality and continued transmission.
Access to accurate diagnosis is also a major challenge for children with suspected TB, and in people with HIV co-infection, who often present with disseminated or extrapulmonary disease, explained Pai.
Even when patients seek care, and diagnostics is used, lack of a highly sensitive test at the primary care level limits the effectiveness of care.
Without drug susceptibility testing to assess drug resistance, a patient with MDR TB may receive inappropriate treatment – leading to a risk of treatment failure in the individual, and drug resistance in the wider
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