david's web-log

Today, March 24th, is World TB Day. I’m not an infectious disease expert (or, honestly, even a infectious disease amateur), but you don’t need to be one to understand the the basic epidemiology (incidence, distribution, and control) of TB. Some facts from the World Health Organization:

Fact #1: Tuberculosis (TB for Tubercle Bacillus) is a contagious disease caused by a bacterium. It spreads through the air like the common cold.

Fact #2: TB kills about two million people each year. In developing nations, where the spread of the disease verges on a pandemic, standard TB can not only be treated but cured for about $16.

Fact #3: Overall, about one-third of the world’s population carries the TB bacterium. However, TB doesn’t usually become infectious and deadly unless the immune system is suppressed. Those in developing nations are disproportionately affected by TB, then, as they are more likely to live in crowded areas, suffer from poor nutrition, and have limited access to basic health care. This is why TB is sometimes referred to as a “disease of the poor.”

Fact #4: HIV and TB do not go well together because HIV weakens the immune system. In fact, TB is the single leading direct cause of death among people who are HIV-positive.

Fact #5: Sometimes, TB mutates and becomes resistant to one or more of the drugs used to treat it. Drug resistance is far more likely when the treatment for a TB patients is incomplete or inadequate. Multi-drug resistant TB (MDR-TB) is defined as resistance to the two most effective TB drugs. The fear is that efforts to treat standard TB might increase the prevalence of MDR-TB, which is more complicated and expensive to treat.

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For more information, please check out the exceptionally well-written and well-sourced Wikipedia article on tuberculous here, World TB Day articles here and here, and a World Health Organization fact sheet here.