Surprising number of people have TB; most probably don't even know they have it.
I work with military, and a lot of Vets; one found out after his wife took him to a regular ED, he found out that he had been on her insurance for years, not just the VA insurance. He had been in the VA ED a few times for Shortness of Breath and they kept telling him it was a respiratory infection. Regular ED told him he has Latent TB. Surprise.