What is a vector that carries pathogens within its body known as?

A vector that carries pathogens within its body is known as a biological vector. This term specifically refers to an organism, often an arthropod like a mosquito or tick, that not only transports pathogens but also plays a role in the life cycle of the microorganism. In essence, the pathogen undergoes some developmental or reproductive stages within the biological vector before being transmitted to a new host.

In contrast, a mechanical vector simply carries pathogens on its body without the pathogens undergoing any development inside it. Such vectors can transfer pathogens from one surface to another but do not contribute to the lifecycle of the pathogens themselves. The choice of bacterial vector is not commonly used in this context; it does not define a particular type of carrier in microbiological terms. Lastly, an environmental vector typically refers to non-biological entities or elements, like soil or water, that may harbor pathogens but do not actively carry them within a living organism. Thus, biological vector is the correct term compatible with the described functions of disease transmission and pathogen lifecycle involvement.