PREVENTION
Epidemiology, with its emphasis on identifying the antecedents of disease, offers the opportunity for disease prevention. Different preventive measures can be applied at different stages in the natural history of the disease.

Primary prevention
Primary prevention is the prevention of the future occurrence of a disorder in unaffected individuals by removing　a cause, e.g. preventing lung cancer by avoiding smoking or preventing an infectious disease by increasing host resistance, either by general measures (e.g. nutrition) or by specific measures(e.g. immunisation).

Secondary prevention
Secondary prevention is the prevention of overt (clinical) cases of a disorder through screening and early detection followed by appropriate intervention, e.g. breast cancer screening by mammography.　
The treatment of clinical disease, while not normally regarded as prevention, is sometimes referred to as tertiary prevention, as effective treatment of overt disease can often prevent disability and pain resulting from the disease.

翻訳例　と　ライティング例　　で比較してみてください。