CHN-I-EPIDEMIOLOGY-UNIT -4 Principles of Epidemiology andEpidemiological methodsa) Definition and aims ofepidemiology, communicable andnon-communicable diseases.b) Basic tools of measurement inepidemiologyc) Uses of epidemiologyd) Disease cyclee) Spectrum of diseasef) Levels of prevention of disease.g) Disease transmission – direct andindirect.h) Immunizing agents, immunizationand national immunizationschedule.i) Control of infectious diseases.j) Disinfection. Principles of epidemiology and epidemiological method : Topic: Definition and Aims of epidemiology communicable and non communicable Disease: : To define epidemiology: Introduction: