to track down hundreds of people who may have been in contact with her in several states. >> just the biggest guns that we have as far as our antibiotics would have to be used in this case. and. even when we use those they're still limited effectiveness with this particular type of tuberculosis, xbr tuberculosis. in april she is believed to be travel from india to chicago and then missouri and tennessee before seeking treatment. seven weeks after arriving in the u.s. she was diagnosed with active tb and transfer i'd by air and ground ambulance to the nih. now the cdc and state health departments are trying to contact other passengers on her flight and anyone who might have come in contact with her in at least three states. while the risk of contracting a contagious disease on an aircraft is low, health experts take tb very seriously. >> people who are on that plane with her owe it to themselves and their close contacts to be followed up to see whether they are infected. >> tb bacteria are released into