HEALTH officials are paid to feel apprehensive. For some years they have feared that tuberculosis (TB), an ancient scourge tamed by modern drugs, might evolve into a new, indestructible state. New strains of mycobacterium tuberculosis have already emerged, some resistant to isoniazid and rifampicin, two of the best known treatments, and some resistant to additional injected drugs. The advent of completely resistant TB seemed inevitable. Now it may have arrived. 

On January 17th doctors in Mumbai declared that a dozen patients at Hinduja National Hospital had contracted TB that responded to no treatment. Three had already died. If the claim is proven true, it would usher a new era for an old foe. 

M. tuberculosis does its dirty work mainly in the lungs, where it destroys tissue. A cough, sneeze or even idle chatter can propel the bacterium into the air, then into the lungs of another person. In the 20th century antibiotics helped to quash TB in much of the rich world. But the bacterium has mutated.