How is a "communicable disease" defined in public health?

A communicable disease is defined as a disease that can be transmitted from one individual to another. This transmission can occur through various means, such as direct contact (e.g., touching, kissing), indirect contact (e.g., unwashed surfaces, contaminated water), airborne particles, or through vectors such as insects. The defining characteristic of communicable diseases is their ability to spread between people, which differentiates them from non-communicable diseases that are typically caused by environmental factors, lifestyle choices, or genetic predispositions and cannot be transmitted from person to person. Understanding this concept is crucial in public health as it informs control and prevention strategies for disease outbreaks and the implementation of measures to protect community health.