How is a contagious disease defined?

A contagious disease is defined as one that can be spread from one person to another. This characteristic is essential in understanding how infections are transmitted within populations. Contagious diseases typically spread through various means, such as direct contact, respiratory droplets, or through surfaces contaminated with pathogens.

Understanding this definition is crucial for infection control practices, particularly in settings like salons or healthcare facilities where the risk of transmission must be minimized. For instance, practices like proper sanitation, hygiene measures, and vaccination can help control the spread of these diseases.

Options that mention the need for hospitalization, that a disease cannot be transmitted between people, or that it is always fatal do not align with the definition of contagious diseases. These criteria address aspects of disease severity or outcomes rather than the ability to spread the disease from person to person, which is the core of what makes a disease contagious.