Which statement best defines communicable disease?

Which statement best defines communicable disease?

• A. Those diseases that can be transmitted from one host to another
• B. Diseases caused by non-infectious agents
• C. Diseases that can be prevented only by vaccination
• D. Diseases that affect only animals

Answer: (A)

Communicable disease is defined by its ability to spread from one host to another. This transmission between hosts—through direct contact, droplets, airborne routes, contaminated food or water, or vectors—defines what makes a disease communicable. Illnesses like flu or measles illustrate this spread. Diseases caused by non-infectious agents aren’t communicable because there’s no pathogen moving between people. The idea that prevention is possible only by vaccination isn’t correct, since many communicable diseases have other prevention methods and vaccines don’t stop all transmission. And diseases that affect only animals aren’t required for the definition, since many communicable diseases can affect humans too. So the statement about transmission from one host to another is the best fit.

Communicable disease is defined by its ability to spread from one host to another. This transmission between hosts—through direct contact, droplets, airborne routes, contaminated food or water, or vectors—defines what makes a disease communicable. Illnesses like flu or measles illustrate this spread. Diseases caused by non-infectious agents aren’t communicable because there’s no pathogen moving between people. The idea that prevention is possible only by vaccination isn’t correct, since many communicable diseases have other prevention methods and vaccines don’t stop all transmission. And diseases that affect only animals aren’t required for the definition, since many communicable diseases can affect humans too. So the statement about transmission from one host to another is the best fit.