Scientists have found a hiding place in the body where bacteria that cause tuberculosis may take refuge — a clue that could one day help target treatments more effectively and surmount a major obstacle to eradicating the global epidemic.

The tuberculosis microbe’s ability to hang around, dormant, for as long as a lifetime has long been a mystery and a public health problem: 2.2 billion people worldwide are infected with TB, 90 percent with latent infections that cause no symptoms but could be reawakened.