What is a communicable disease?

• A. A disease that cannot be transmitted.
• B. A disease that can be passed from one person to another.
• C. A disease caused by bacteria only.
• D. A disease that is always fatal.

Answer: (B)

Communicable disease means an illness caused by a pathogen that can be transmitted from one person to another (or from animals to humans). The defining idea here is transmission between hosts, through direct contact, airborne droplets, contaminated surfaces, vectors like mosquitoes, or contaminated food and water. That’s why the option describing a disease that can be passed from one person to another is the best fit.

Many illnesses are communicable because they’re caused by bacteria, viruses, fungi, or parasites and can move between people by these routes. At the same time, not all diseases are transmissible—some are non-communicable, like many chronic conditions. Also, a disease isn’t defined by being fatal or by being caused only by bacteria; it can be caused by various pathogens and have a range of outcomes.