A susceptible host is a member of a species population who is at risk of becoming infected with a certain disease due to a variety of reasons. Susceptible hosts differ from the general population because they are far more likely to get infectious diseases than the general population.
Susceptible hosts have a myriad of reasons for their classification. Their susceptibility is due to risk factors that can arise from the individual itself or from the individual's environment. Examples of risk factors include poor personal hygiene, poor control of infection throughout the environment and the age of the host. These factors all contribute to the host's ability to become easily infected with a disease when exposed.