Host and vector parasite infections may be carried from one host to another by means of arthropod vectors. A vector may also be a host if development of the parasite takes place with its body. (If the arthropod is simply an instrument of passive transfer, we refer to it as a mechanical vector)Host and vector parasite infections may be carried from one host to another by means of arthropod vectors. A vector may also be a host if development of the parasite takes place with its body.(If the arthropod is simply an instrument of passive transfer, we refer to it as a mechanical vector)