Table 7.

Host Factors that Influence Exposure, Infection, and Diseas e

Factors that influence exposure
Behavioral factors related to age, drug usage, alcohol consumption	Military service
Familial exposure	Occupation
Hospitalization, especially intensive care	Recreation, sports, hobbies
Hygienic habits	Sexual activity: hetero- and homosexual, type and number of partners
Institutionalization: nurseries, day-care center, homes for the elderly and	Socioeconomic level
mentally retarded, prisons and other closed environments	Travel, especially to developing countries
Factors that influence infection, and occurrence and severity of disease
Age at the time of infection	Entry portal of organism and presence of trauma at site of implantation
Alcoholism
Anatomic defect	Genetic makeup, especially influences on the immune response
Antibiotic resistance	Immune state at time of infection
Antibiotic in tissues	Immunodeficiency: natural, drug-induced, or viral (HIV)
Coexisting diseases, especially chronic	Mechanism of disease production: inflammatory, immunopathologic, or toxic
Dosage: amount and virulence of organism to which person is exposed
Double infection	Nutritional status
Duration of exposure to organism	Receptors for organism on cells needed for attachment or entry of organism