采矿业让结核病在南非洲流行

Some of the main driving factors of sub-Saharan Africa’s growing tuberculosis epidemic can be found deep underground in its gold, diamond and precious mineral mines.  A new Oxford University-led study warns of the health risks faced by miners and their families.

The study says Africa’s mining industry “may be implicated” in as many as 760,000 new cases of TB every year.

Lead author, Oxford researcher Dr. David Stuckler, says, “It’s well known that miners have the highest risk of tuberculosis of any occupational group in the world, especially in sub-Saharan Africa.  But the striking finding of our study was that not just miners are at risk.  But through a system of circular migration, these risks are spread to their families, communities and entire countries."

Dust, crowding, HIV

“In gold mines, such as those in South Africa, there are high levels of silica.  This is known to create risks over the long-term of silicosis, which damages the lungs and puts miners and workers at risk of contracting or activating tuberculosis,” says Stuckler.

The miners’ poor living conditions also make them more vulnerable to TB.

“Miners travel long distances and seasonally, living in barracks and hostels at the mines.  Often these are cramped and poorly ventilated quarters sometimes referred to by researchers as prison-like in their size and scope.  This creates conditions that are conducive for spreading an airborne disease rapidly,” he says.

And then there’s HIV/AIDS, the spread of which is now linked to TB.  Stuckler says the study shows that African countries with the greatest intensity of mining activity also have the greatest rates of tuberculosis and HIV.

Stuckler says, “Due to the transitory nature of the work, miners are often away from their families for extended periods.  This can lead to risky sexual activity.  Sexworkers locate often alongside mines and peripheral mining communities and in a setting where HIV prevalence is very high.  In some cases as many as 2 out of 5 people are infected.”

Early treatment not enough

Many mining companies have health clinics that can diagnose miners with TB and start treatment.  However, the study says that doesn’t go far enough to stop the spread of the disease.

“When that miner travels home,” he says, “often the medicines and medical records of the miner do not.  So when the miner reaches Swaziland or Lesotho, a doctor recognizes signs of tuberculosis.  He or she is often working blind, not knowing what medicines the miner has or hasn’t taken.  In this case, there’s potential for treatment disruptions, medical mismanagement that can breed drug resistant strains.  Those drug resistant strains threaten us all.”

The Oxford researcher adds, “One study in Lesotho found that 1 out of 4 cases of extensively drug resistant tuberculosis – this is a strain of the disease that’s virtually resistant to our main tuberculosis drugs – one quarter of those cases was occurring in miners, ex-miners and their families.  We’re seeing strong evidence that through migration a disease becomes an epidemic."

The study of sub-Saharan African mining and TB was a joint effort by researchers at Oxford and Brown Universities, the University of California at San Francisco and the London School of Hygiene and tropical Medicine. It recommends that mining companies and governments work together to ensure “transparent, accountable standards” of cross border care.  The study also calls for early screening of miners.

“A policy of simply dismissing miners from work when they show signs of tuberculosis will not work and creates a broad set of costs and risks to entire societies,” he says.

The study says over the past 20 years, there’s been a doubling of the yearly annual incidence of TB.  It now infects about 350 out of every 100,000 people in sub-Saharan Africa.  That’s despite the spending of tens of billions of (US) dollars on TB-related programs.

The study was published in the American Journal of Public Health.