Communicable diseases such as encephalitis, meningitis, tetanus, rabies, poliomyelitis, dengue, malaria, leptospirosis, diphtheria, pertussis and measles are discussed. For each disease, the causative agent, modes of transmission, incubation period, signs and symptoms, diagnostic tests, medical treatment, nursing management and prevention are summarized. The document provides an overview of major communicable diseases affecting different body systems and chains of infection.