Modified Diagnostic approach and Molecular Epidemiology of Childhood Tuberculosis in Hawassa, Ethiopia By Moges Desta Ormago A Dissertation Submitted to the School of Graduate Studies of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Microbial, Cellular and Molecular Biology (Applied Microbiology) June, 2018 Addis Ababa, Ethiopia