Vectors and reservoirs

Many infectious diseases may be transmitted through a vector. A vector is an organism that acts as a carrier of an infectious agent between organisms of a different species (Wilson, 2017). Most commonly, vectors are arthropods, such as mosquitos or ticks. Vectors can serve as a purely mechanical transport between individuals or can serve as a necessary intermediate in the pathogens lifecycle.

A reservoir is the environment in which a pathogen population in maintained and could include humans, animals, and the environment (CDC, 2012). Many emerging pathogens have wildlife reservoirs, i.e. the pathogen circulates in a wild animal population normally with some risk of spillover to people. Pathogens that can be transmitted between vertebrate hosts and humans are considered zoonoses. Zoonotic diseases are often (but not always) transmitted by a vector.