LIKE every dog, every disease now seems to have its day. World Tuberculosis Day is on Saturday March 24th. On the same day in 1882 Robert Koch, a German bacteriologist, presented his discovery of Mycobacterium tuberculosis to a meeting in Berlin. That announcement helped to establish the germ theory of disease—the idea that contagious illnesses are caused by specific micro-organisms.
According to figures released earlier this week by the World Health Organisation, 1.6m died of the disease in 2005, compared with about 3m for AIDS and 1m for malaria. But it receives only a fraction of the research budget devoted to AIDS. America's National Institutes of Health, for example, spends 20 times as much on AIDS as on TB.