In the same way, the population dynamic of the infectious class grows with the occasional break down of latent TB into infectious TB. This class also reduces by natural death rate U and successful cure of infectious TB patients at the rate Y and death caused as result of chronic TB infection at the rate B. Lastly, the dynamics of the recovered class increases with successful cure of latent TB patients at the rate B and that of infectious TB patients at the rate Y and decreases by natural death rate B.