The person, animal, object or substance from which an infectious substance passes or is disseminated by host is called source of an infection.a reservoir is defines as any person,animal,ahropod,plant,soil,or substance in which an infectious agent lives multiplies ,on which it depends primarily for survival,and where it reproduces itself in such a manner that it can be transmitted to a susceptible host. ref:park&;s textbook,ed 22,pg no 91