The recent Declaration and Code of Conduct on TB in the Mining sector signed by the SADC Ministers of Health are a recognition of the close link between mining and TB in sub-Saharan Africa. Not only does silicosis increase the risk of TB by about 3 times on average, but the working conditions and the living conditions in the mine hostels, especially around gold mines, are such as to greatly enhance the spread of TB.
HIV infection drives the epidemic of TB partly because people living with HIV are more susceptible to being infected with TB and also because those with a latent TB infection, which in some places may be up to 80% of the adult population, are more likely to break down to active disease.
For most of the past century the system of oscillating (going to and from) labour migration, especially to the gold mines in South Africa, has helped to spread TB throughout southern Africa and it now helps to spread HIV. However, there is also evidence that other forms of migrant and seasonal labour have contributed to the spread of both infections.