Tuberculosis is one of the oldest recorded communicable diseases. Egyptian mummies are testimony that this contagion has been around for millennia. Yet researchers are still challenged by the scourge.
The most common form of TB is pulmonary tuberculosis, which affects the lungs and is spread through airborne droplets produced when an infected person laughs, coughs, sings or sneezes.
TB became particularly virulent during the days of the industrial revolution, no doubt because, for the first time in history, the masses were compelled to live in close proximity to one another. The unhygienic slums of the 19th and early 20th centuries became rich breeding grounds for the bacteria Mycobacterium tuberculosis.
And the malnourished bodies of the people living in these overcrowded conditions became ready hosts for infection. Vaccines such as BCG were developed in the early 20th century, but their efficacy was always in doubt. It wasn’t until the mid 1940s, when the antibiotic, streptomycin was developed that a truly effective treatment finally came to the fore.
By the 1950s antibiotic-based cures were being prescribed on a mass level through well organised public-health campaigns that swept across the Western world. And the virulence of TB abated.
But, like some odious character in a low-budget horror movie who makes an abrupt reappearance long after the audience thinks he’s been eliminated, TB also staged an alarming resurgence. And like that genre of movies, the sequels are always worse than the original.
By the late 1980s and 1990s drug resistant strains of TB (DR-TB) and strains of TB resistant to multiple drugs (MDR-TB) started making themselves known. This resurgence was deemed so serious that in 1993 the World Health Organisation declared TB a global emergency.
Then, the most alarming development to date occurred. In 2006, at a hospital in Tugela Ferry, KwaZulu-Natal, 53 patients (virtually all of them HIV positive) contracted a strain of TB that was resistant to virtually every antibiotic. Called Extreme Drug Resistant TB (XDR-TB), it has since rapidly spread to various parts of the world and has alarmingly high mortality rates.
Why the resurgence of TB?
So why this resurgence of TB when drugs had proved their efficacy for at least three decades? The reason can be attributed to on the capriciousness of human beings.
Patients who did not take their medication as directed, or patients who stopped taking their drugs before the full course was completed led to the mutation of the Mycobacterium tuberculosis bacteria. That in turn caused strains becoming immune to the original drugs prescribed, making TB far more difficult to treat.
Since then these mutating strains have compelled pharmaceutical companies to play a constant game of “catch up” and develop more potent drugs.
Particularly alarming is how DR-TB and XDR-TB have had such a devastating effect on the South African population.
The reasons for this should come as no surprise. The close correlation between TB and HIV is well documented. And as HIV severely weakens the immune system, those with Aids have no resistance to TB. (And vice versa, as TB sufferers are more susceptible to contracting HIV.)
TB is also associated with mining. A person suffering from silicosis — endemic among miners — is believed to be 30% more likely to contract TB than someone without silicosis.
We can also point fingers at socioeconomic issues. Are the people who live in South African shanty towns better off than the slum dwellers of the 19th century? Are they better nourished? Do they live in more hygienic conditions? Do they have ready access to educational information and preventative care?
These are just a few of the many tough questions that need to be asked if we are ever to relegate TB to what it should be: a disease of the past.