The basic reproductive rate is affected by several factors, including the duration of infectivity of affected hosts, the infectiousness of the organism, and the number of susceptible individuals in the population that the affected hosts are in contact with. These basic concepts are expanded upon in the references provided below. Instructors unfamiliar with นิเวศวิทยาโรค are strongly encouraged to read and understand these references to provide the foundational knowledge required to effectively implement the proposed learning activities below.