Not only poverty but also specific occupations can raise the risk of infectious disease.

As long ago as 1903 it was first recognised in South Africa that miners were more likely to develop tuberculosis than other people in the country. The same has been noted in other countries and it is believed that damage to the lungs through the inhalation of silica dust makes it easier for the infection to develop.

But South Africa’s miners now experience such very high levels of TB infection - around 7,000 cases per 100,000, ten times that of the rest of the population and very much higher than that found in miners in developed countries - that silica dust cannot be the only risk factor involved. Living and working conditions are also a cause for concern. Mine shafts are crowded and poorly-ventilated, and so are hostels where over a dozen men can share a small room. These conditions are highly conducive to the spread of infection.

The issue is discussed in a “Debate” article in the journal Globalization and Health. The authors state that, “The problem is not simply one of differential occupational hazards, but of the social context for transmission and the interaction between miners and the rest of the population”.

The article goes on to discuss the measures that can be taken to reduce miners’ TB risks, noting that - as South Africa’s mining industry is currently experiencing a boom - this is the time for such measures to be introduced.