What term describes a living or non-living carrier that transmits a pathogen between hosts (for example via water, air, or animals)?

• A. Reservoir
• B. Fomite
• C. Transmission vector
• D. Droplet

Answer: (C)

A transmission vector is the carrier that moves a pathogen from one host to another. It can be living, like a mosquito that spreads malaria, or in broader contexts even nonliving media such as water or air that transport the pathogen to new hosts. The key idea is the role of the carrier in facilitating transfer between hosts. This is different from a reservoir, which is the environment or organism where the pathogen lives and persists, not necessarily the immediate conduit of transmission; a fomite refers to an inanimate object that can carry pathogens, and a droplet is a mode of transmission rather than the carrier itself. So the term that best matches the description of a carrier that transmits between hosts is transmission vector.