This document discusses the prevention of communicable diseases. It defines communicable diseases and describes their modes of transmission, including direct contact, droplets, vectors, fomites, and vehicles. It lists many prevalent communicable diseases in India like respiratory infections, intestinal infections, arthropod-borne diseases, zoonoses, and hospital-acquired infections. It provides tips for disease prevention such as handwashing, vaccination, appropriate antibiotic use, isolation when sick, safe food handling, and cleaning. The role of doctors is outlined as controlling reservoirs, interrupting transmission, protecting susceptibles, and implementing non-specific measures.