TB stands for tuberculosis. It’s an infectious bacterial disease caused by Mycobacterium tuberculosis, which most commonly affects the lungs. It is transmitted from person to person via droplets from the throat and lungs of people with the active respiratory disease.

Like all other World Days regarding infectious diseases, it is meant to raise awareness about its global epidemiological aspects and the efforts to eliminate it. For tuberculosis, March 24th was chosen because Robert Koch first described Mycobacterium tuberculosis on March 24th, 1882. He then received the Nobel Prize in Physiology or Medicine for this in 1905.

On the WHO website, there is a huge amount of data that can be easily parsed (here too).

I was first interested in the estimated TB incidence per 100 000 population in 2009 (per 100,000 population) in the BRIC countries (see table below). Clearly, there is Brazil with a low incidence (compared to others, it’s still around 10 times values found for “occidental” countries) then Russia and China around 100 cases/y and finally 168 cases/y for India. I added their respective Gross Domestic Product (GDP) in the table as it’s often considered as an indicator of a country’s standard of living (in 2009, numbers from Wikipedia/IMF). I also added the annual growth rate of GDP per capita (in 2006, numbers from EarthTrends/World Resources Institute). The only interesting thing I see is that if your annual growth of GDP per capita is low, your estimated TB incidence per 10,000 is also low.

Country	Est. incidence	GDP per capita	Annual growth rate …
Brazil	45	11,289	2.4
China	96	7,518	10.1
India	168	3,290	7.7
Russian Federation	106	15,807	7.2

Now if we look at some occidental countries (table below, same sources), this seems right.

Country	Est. incidence	GDP per capita	Annual growth rate …
Belgium	8.6	36,274	2.6
France	6.1	34,092	1.4
Germany	4.9	35,930	2.9
Japan	21	33,828	2.2
UK	12	35,053	2.2
USA	4.1	47,123	1.9

The treatment involves medications for long period and is usually accompanied by antibiotics. Regarding prevention, Bacille Calmette Guerin (BCG) is the only current vaccine for tuberculosis and contains a live attenuated (weakened) strain of Mycobacterium bovis. TB eradication is part of the UN Millenium Development Goals (Target 6c: Have halted by 2015 and begun to reverse the incidence of malaria and other major diseases). It is also part of the WHO Global Plan to Stop Tuberculosis.

Recently (because of this World TB Day?), two interesting research papers were recently published in the litterature:

• Wang et al. published a dynamic model for tuberculosis transmission (with focus on South Korea)
• Backus et al. created a technique that could be used to follow how the bacterium infects macrophages

• Health