sentences:  A study of cost-effective strategies for tuberculosis control supported three major policies.First, the treatment of smear-positive cases in DOTS programs must be the foundation of any tuberculosis control approach, and should be a basic practice for all control programs.Second, there is a powerful economic case for treating smear-negative and extra-pulmonary cases in DOTS programs along with treating smear-negative and extra-pulmonary cases in DOTS programs as a new WHO "STOP TB" approach and the second global plan for tuberculosis control.