In the beginning of the chapter, you learned how microbes enter the body through a preferred route, or portal of entry. Microbes also leave the body via specific routes called portals of exit in secretions, excretion, discharges,or tissue that has been shed. In general, portals of exit are related to the part of the body that has been infected. Thus , in general, a microbe uses the same portal for entry and exit. By using various portals of exit, pathogens can spread through a population by moving from one susceptible host to another. As you learned in chapter 14, this type of information about the dissemination of a disease is very important to epidemiologists