Communicable Diseases

Communicable diseases are infections caused by microorganisms such as bacteria, viruses, fungi, and parasites that can spread from one person to another directly or indirectly. They remain a major global public health challenge despite advances in medicine and vaccination. Disease occurrence is influenced by the interaction of the host, agent, and environment. Transmission occurs through direct contact, respiratory droplets, contaminated food and water, vectors, fomites, and healthcare procedures. Major categories include respiratory infections, intestinal infections, vector-borne diseases, zoonoses, and healthcare-associated infections. Diseases such as influenza, measles, hepatitis, malaria, dengue, and Japanese encephalitis contribute significantly to morbidity and mortality. Prevention relies on vaccination, sanitation, vector control, health education, early diagnosis, and surveillance. Effective public health strategies are essential to reduce disease burden and improve community health.