Rapid industrialization, improved transportation, increasing opportunities to improve socio-economic conditions and attractions for tourism resulted in rapid growth in urbanization. Chronic communicable diseases such as leprosy, TB, HIV/AIDS started emerging as major public health problems in fast developing metropolitan areas/cities/towns. Even in USA, 80% of the new cases are from migrated population from Endemic countries; thus maintaining low level of disease transmission. (NHDP Report, 2001).

http://bphc.hrsa.gov/nhdp/Epidemiology_CLINICAL_CARE.htm