Global prevalence of chronic pulmonary aspergillosis following pulmonary tuberculosis

Tuberculosis (TB) is a common and often deadly disease caused by strains of mycobacteria. It attacks the lungs but can affect other parts of the body. Most infections are latent and asymptomatic – about 10% go on to develop active disease, which if untreated is fatal for about 50% of cases. One of the consequences of pulmonary TB is the development of chronic pulmonary aspergillosis (CPA).

The symptoms of TB are chronic cough, blood stained sputum, fever, night sweats and weight loss. These symptoms are remarkably similar to those of chronic pulmonary aspergillosis which could mean that CPA was underlying and undetected. Approximately one third of the world’s population is thought to be infected with mycobacterium tuberculosis, predominantly in the developing world.

In 2007, WHO estimated 7.7million cases globally with 77% having a one year survival. A recent presentation to the British Thoracic Society in London (Denning et al) – analysing the global prevalence of CPA following TB, estimates that 372,000 patients worldwide developed CPA after TB in 2007. The distribution showed a predominance of cases in Africa (98,000), W Pacific (88,800) and SE Asia (145,700). The occurrence will be complicated where immunosuppression and HIV are more prevalent.

The analysis concludes that CPA after TB is a significant public health problem in SE Asia, Africa and W. Pacific areas, but that a lack of research, limits precise estimates of cases, both regionally and globally.