Define infectious period.

• A. Follows latent period and is the period when host transmits the agent
• B. Period when not contagious
• C. Period of exposure
• D. Period after recovery

Answer: (A)

Infectious period is the window during which an infected person can transmit the pathogen to susceptible people. It starts after the latent period—the time from infection to becoming contagious—and ends when the person is no longer contagious (often with recovery, clearance of infection, or isolation). This period may occur with or without symptoms, depending on the disease. The description that it follows the latent period and is the period when the host transmits the agent precisely captures this concept. The other options describe times when transmission isn’t occurring (not contagious), times before infection (exposure), or after recovery (no longer infectious).