There are a number of definitions of epidemiology described by different authors but the most suitable definition is that epidemiology may be defined as the detailed scientific study of the distribution and determinants of disease or disability in society.
These studies cover sources and modes of transmission of an infection occuring endemically or erupting as an epidemic in the community. It also covers the social, economic and environmental factors. Earlier the term epidemiology was referred to only those communicable diseases which used to spread in epidemic form like small-pox, cholera, plague etc.
but now a day’s epidemiological studies include communicable, non-communicable, nutritional and deficiency diseases.
Uses of Epidemiology:
Following are the major uses of epidemiology: (i) To study the history of disease in relation to its rise and fall in a community. (ii) To study the respective role of agent, host and environmental factors in the spread of disease. (iii) It helps in the study of types of diseases prevalent in a community. (iv) It helps to diagnose the health problems of the community by studying occurrence, distribution by age, sex, occupation and locality.
(v) It helps to find out the morbidity and mortality rates and to identify those individuals or groups at risk or those in need of health care. (vi) It helps to collect variety of data from different sources which will establish logical chains to explain multiple factors in the spread of a disease. (vii) It helps to establish epidemiological diagnosis of a disease with better understanding of its different aspects after observing its behaviour in a group of persons. Thus effective preventive and control measures can be adopted. (viii) It helps in research and experimental studies in the field of medical science. (ix) It helps to forecast the future trends of the disease which will help to take preventive measures e.g.
increased incidence of cholera in summer season and malaria during rainy season. Though the communicable diseases have been controlled in the developed countries but the non-communicable diseases are on the increase. In under developed or developing countries both communicable and non-communicable diseases are increasing. With the fast urbanisation and industrialisation there is an increased trend in the cases of various malignancies, cardio-vascular diseases, mental and psychosomatic problems, occupational and industrial hazards, accidents etc. In such cases epidemiological studies are carried out on the basis of which preventive and remedial measures are worked out to lessen the intensities of these problems.
So the ultimate and final goal of epidemiologists is to study various aspects of diseases and suggest measures for the eradication of the diseases and other problems as far as it is practicable, so as to lessen the sufferings of mankind.