A living creature that transmits an infectious agent to a human is called

• A. Vector
• B. Fomite
• C. Reservoir
• D. Portal of exit

Answer: (A)

Understanding how an infectious agent moves from a living carrier to humans is being tested. A vector is a living organism that transmits a pathogen from an infected host or reservoir to a susceptible human, often by a bite or other interaction that introduces the pathogen into the body. Examples include mosquitoes spreading malaria or dengue, ticks transmitting Lyme disease, and fleas carrying plague.

A fomite, by contrast, is an inanimate object that can harbor pathogens and pass them to a person who touches it. A reservoir is the natural habitat where the pathogen lives and multiplies, which may or may not involve direct transmission. A portal of exit is the route by which a pathogen leaves a host, such as through coughing, sneezing, or blood, rather than the carrier itself.