Tuberculosis

Tuberculosis is the single deadliest infectious disease in human history by total mortality. Caused by the airborne bacterium Mycobacterium tuberculosis, it has been part of human experience since at least 9000 BCE, with evidence of TB lesions in Neolithic skeletons. It became a true pandemic during the urbanisation of 18th- and 19th-century Europe, when it caused an estimated 25% of all adult deaths in England and France at mid-century.

Before antibiotics, tuberculosis was largely untreatable. Victims typically survived for years with chronic symptoms — bloody cough, wasting, night sweats — giving rise to its common name "consumption." The romanticised image of the pale, doomed consumptive permeated 19th-century art and literature; major figures who died of it include John Keats, the Brontë sisters, Frédéric Chopin, Anton Chekhov, and George Orwell.

The discovery of the tuberculosis bacillus by Robert Koch in 1882 enabled diagnostic and preventive work. Streptomycin (1944) and isoniazid (1952) provided the first effective antibiotic treatments. Despite antibiotics and the BCG vaccine, TB remains a major killer today — roughly 1.25 million annual deaths — with multidrug-resistant strains posing a growing threat.