Communicable Disease - GCSE Biology Definition

A communicable disease is an illness that can spread from one person to another, or from animals to people. This happens through pathogens like bacteria and viruses, or parasites. These pathogens can travel through the air when someone coughs or sneezes, or by touching things that an infected person has touched, like door handles or phones. Communicable diseases include common colds, flu, and more serious illnesses like tuberculosis and COVID-19. Understanding how these diseases spread helps us know how to protect ourselves and others, like by washing our hands and getting vaccinated.