But it's believed that the majority of cases of tuberculosis, that we actually see, are so called post-primary tuberculosis where all of this process is taking place asymptomatically  and  the host is in this state of balance but something else comes along and stresses cell mediated immunity  and the control breaks down so that th the organism M T B  wins out very dramatically over the, over the macrophages and you end up with this post-primary pattern  of tuberculosis.