Tuberculosis progression from latent infection to active disease varies greatly. For instance, people with AIDS are more likely to develop to active TB after infection. A patient with AIDS who becomes infected with Mycobacterium tuberculosis has a 50% chance of developing active tuberculosis within 2 months and a 5-10% chance of developing active disease each year thereafter. According to the World Health Organization(WHO), infants and young children infected with Mycobacterium tuberculosis are also more likely to develop active TB than older people since, their immune system are not yet well developed(Okyere,2007)