A couple of transit workers are confirmed have contracted TB, according to health officials, prompting many to scratch their heads in surprise. The airborne disease, best-known for killing millions of people during the 19th and early 20th centuries, is still fairly common in Africa and Asia but very rare in the U.S. Though it’s now treatable, people are still worried. Several nearby shop owners and employees have expressed concern; talk of wearing masks has even emerged. City health officials, still unsure as to how the workers contracted the illness, are working as quickly as possible to keep the mini-outbreak contained.