Occupational lung disease among Basotho ex-miners in a large outreach medical assessment programme

Background: Current initiatives in southern Africa to medically assess former migrant miners for silicosis and tuberculosis, including statutory and lawsuit derived compensation programmes, require burden of disease information. nObjective: To use clinical information collected on ex-miners examined at the Occupational Health Service Centre (OHSC) in Lesotho, operated under the Tuberculosis in Mining Sector in Southern Africa (TIMS) project, to measure the burden of lung disease and respiratory impairment. Methods: Demographic, occupational and medical history information, chest radiology, spirometry, GeneXpert testing for tuberculosis, and pulse oximetry outcomes were analysed, and descriptive summary measures calculated, in a group of ex-miners examined in 2017 and 2018. Results: The study sample comprised 2 758 Basotho former underground miners, with median age of 62 years and median length of service of 28 years. Among ex-gold miners (n = 2 678), disease prevalence was high: radiological tuberculosis (consistent with previous or current disease) 60.9%, silicosis 42.5%, HIV 30.7%, silicotuberculosis 25.7%, and current active tuberculosis 6.8%. Of those with tuberculosis diagnosed microbiologically, 6.7% had no radiological evidence of tuberculosis and 54.1% did not report cough. Conclusion: The findings have public health and compensation implications. There are large numbers of ex-miners with potentially compensable disease under both the statutory system and a settlement trust set up following litigation. This overlaps with a tuberculosis-HIV co-epidemic which requires screening and treatment for tuberculosis and HIV, and managing a considerable disability and care burden on families and the Lesotho health system. Coordinated planning and substantial resources are needed for these programmes to do justice to their mandates

Digital radiological surveillance of silicosis and related tuberculosis in the South African mining industry practical and technical considerations

The switch from analogue to digital radiography formats for surveillance for silicosis and tuberculosis in the South African mining industry raised the question of equivalence of formats for this purpose. As a result, the South African Mine Health and Safety Council (MHSC) sponsored a study, recently published, on the equivalence of digital and analogue radiography in this setting. This commentary aims to provide a summary of the study findings, accompanied by an overview of the practical considerations that arise in the use of digital radiographic surveillance in the South African mining industry. Through a clear understanding of the objectives of surveillance, use of quality and reference standards for hardware and software, and interpretation of digital images, avoidance of common pitfalls, and use of all the clinical and occupational health information on each miner, the contribution of surveillance to identification and control of silicosis and tuberculosis in the mining industry can be maximised

A case of silicosis and progressive massive fibrosis with uncertain occupational exposure to silica

A case of histologically diagnosed silicosis with progressive massive fibrosis (PMF) and low dust exposure is reported. Two experienced occupational medicine practitioners took a detailed exposure history on three occasions. The only reported dust exposure was indirectly from coalcarrying conveyor belts in a power station for 23 years; where he worked as a clerk. The chest radiographs showed features consistent with PMF in 1994; after only 11 years of indirect dust exposure. Two pathologists independently reported PMF. The case demonstrates that even when heavy exposure is thought to be required to produce an occupational disease; the source of exposure may be difficult to ascertain

Elimination of silicosis: to eliminate which silica?

International and national programmes to eliminate silicosis have been initiated with the inference that exposure to quartz is associated with silicosis. Experimental evidence is presented by numerous investigators to indicate that pathogenicity of the polymorphs of silica is related to their crystalline structure; origin; and various surface properties. As a result; in the risk assessment process; silica cannot be dealt with as a single hazard entity. Accordingly; if elimination of silicosis is to be achieved in South Africa; standard values for quartz; the main crystalline form of silica polymorphs; should be adopted which will be protective enough against the species with the greatest adverse activity existing in the South African working environment