The chain of infection consists of a sequence of events that must occur for a disease or infection to take place. These events are steps that pathogens must take in order to reach a susceptible host. The host may be anyone lacking proper resistance to certain microorganisms. The chain of infection can only be commenced if there is an adequate amount of the infectious agent present. If the virulence of the pathogens is higher so are their chances of causing disease. A source for the microorganisms to harbor and reproduce, also needs be present for the chain of infection to occur. The source is where the pathogens are initially, before spreading to a vulnerable host. Pathogens can be spread from host to host in several different ways; such as,
