My 27 year old sister who is apparently normal based on her physical state was recently diagnosed with PTB through a random x ray, and was started on the anti tb regimen based on her wt, which is 48kg.(Rif,INH PZA, ethambutol). The doctor based her working diagnosis on her chest x ray results. Now she was asked to do AFB smear for 3 days, explaining that the result of which will tell us if its active or not. As claimed by my sister she never felt any of the classic signs and symptoms of PTB prior to her diagnosis. Is that possible, not having to experience any of those symptoms and still get the disease anyway? and will she still transmit the disease even under medication? thanks!