Infectious disease is often used synonymously with which term?

• A. Communicable disease
• B. Noncommunicable disease
• C. Genetic disease
• D. Degenerative disease

Answer: (A)

The key idea is transmission. Infectious diseases are caused by pathogens and are defined by their potential to spread from one host to another or from the environment to people. Because the ability to pass from one person to another is what makes an infection recognizable as contagious, the term that best aligns with infectious disease in everyday public health usage is communicable disease.

Keep in mind that some infections don’t spread easily between people (for example, certain environmental exposures or infections that require very specific conditions), but in typical public health contexts, infectious is treated as synonymous with communicable because transmission between hosts is the defining concern. The other options describe conditions that are not spread between people: noncommunicable diseases aren’t transmitted, genetic diseases are inherited, and degenerative diseases involve progressive deterioration rather than transmission.