A new way of tackling tuberculosis (TB) in the gold mining industry could cut prevalence rates and the cost of the treatment, compensation and management of TB among SA's mineworkers.
SA's gold mining industry has the highest incidence of TB in the world, with 3%-6% of the industry's 120 000 workers developing the active disease each year. This compare s with a TB incidence of about 0,96% in the general population and negligible rates in developed nations.
TB is legally defined as an occupational disease. In terms of present legislation claimants can obtain compensation from government for pain and suffering, medical expenses and loss of earnings. However, mining companies pay for compensation through contributions to the compensations fund. A study in 1994 by the Chamber of Mines showed that the annual cost of preventing, treating and compensating TB and providing management for the disease across the mining industry was about R700m/year.
The Aurum Institute, a specialist research organisation that focuses on TB and HIV prevention and treatment, estimates that the disease now costs the industry more than R1,2bn/year.
"Over the past two decades, the mining industry has implemented world-leading TB control programmes - but in the era of HIV, these are having little impact on controlling the disease," says Dave Clark, deputy CEO of the Aurum Institute.
The growth of HIV and TB are closely linked (see graph). In the context of reduced immunity linked to the HIV epidemic, TB has become the No 1 cause of death, according to Stats SA. It killed 13 of every 100 people who died in 2006.
The World Health Organisation estimates that almost 1% (461 000) of South Africans develop TB annually, and 40% of HIV-positive patients die of TB.
"Even with the best TB control programmes in force, people living with HIV/Aids are at very high risk of developing active TB over time," says Clark.
It's worse in the mining industry, where a history of migrant labour and the housing of workers in hostels has helped spread the disease. Silicosis, a lung disease caused by workers inhaling dust underground, also creates a "scaffold" in the lungs on which TB bacteria can thrive and multiply. "Our mines are dealing with a triple epidemic of HIV, TB and silicosis," says Clark.
Dave Clarke - High participation rate
But a study done in the 1950s among Alaskan Eskimos offers some hope. It involved administering daily doses of the TB drug Isoniazid as a prophylaxis to prevent TB. After taking the drug for a number of months, TB infection rates in the Eskimo population were radically reduced, by up to 60%. And the protective effect of Isoniazid prophylaxis was shown to persist for more than a year. Now the Aurum Institute is replicating the study in SA.
After securing funding in 2004 of US$27m over seven years from the Consortium to Respond Effectively to the Aids & TB Epidemic, the Aurum Institute began its Thibela TB programme. It used Isoniazid as a prophylaxis at some of SA's biggest gold mines, including those of AngloGold Ashanti, Gold Fields and Harmony. More than 30 000 workers have received the drug over the past four years.
The project had challenges, but it has achieved a volunteer participation rate of 95%. "That's basically unheard of, and represents a phenomenon that could possibly be harnessed to address the prevention of other diseases in communities, too," says Clark.
If the programme is successful, it could help prevent the disease in areas with high TB rates until a vaccine is developed. TB vaccines are being tested, but most are years away from being ready for mass deployment.
"Even if there is a drop of 30% in TB incidence, it would have a huge impact on the mining industry - not only for the bottom line, but in terms of workers' lives too," says Clark.
