Agent: factor whose presence (or absence) is necessary for the occurrence of a disease.
Carrier: individual who harbors a specific infectious agent without visible symptoms of the disease. In the case of violence, a carrier can transmit violence without directly committing an act of violence.
Cluster: aggregation of cases of a disease that are closely grouped in time and place. Frequently the expected number of cases is not known.
Contagion: transmission of a disease from one individual to another through direct contact or indirect exposure.
Disease: condition in which the functioning of the body or a part of the body is interfered with or damaged. Usually the body will show some signs and symptoms of the interference with or damaged functioning and exhibit adverse health outcomes. A disease, such as violence, can be either acute or chronic.
Infectious disease: disease that is caused by the invasion of a host by agents and can be transmitted to other individuals.
Epidemic: occurrence of cases of a disease in a community or region that is in excess of the number of cases normally expected for that disease in that area at that time.
Exposure: instance of being subjected to an action or influence.
Dose exposure: refers to the amount of exposure, which can be along spectrum of acute to chronic.
Immunity: resistance to infection; in the case of violence, an individual’s level of immunity is frequently increased through exposure to protective factors and decreased through exposure to risk factors.
Incubation: period of inapparent infection following disease exposure and ending with the onset of symptoms of apparent infection. In the case of violence, the incubation period varies widely; individuals can be exposed to violence, but not exhibit any violent behavior until a significant period of time has lapsed.
Infection: entry and development of an infectious agent in the body. An infection can be either apparent (showing outward symptoms of illness) or unapparent (showing no outward symptoms of illness).
Interruption: prevention of disease transmission.
Latency: time period between infection and infectivity to others.
Mediators and cofactor: either a risk or protective factor that affects the transmission or prevention and interruption of a disease.
Protective factor: aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that is associated with a decreased occurrence of disease.
Risk factor: aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or inherited characteristic that is associated with an increased occurrence of disease.
Spread: movement of an infectious disease from a vector to a host. In the case of violence, one type of violence can spread virally to multiple cases of the same type of violence, such as suicide clusters. Violence also can spread through a spillover effect, with one type of violence spreading to other types; for example, child abuse can lead to later occurrences of intimate partner violence.
Susceptibility: level of immunity or resistance to a disease. Susceptibility varies depending on mediators and cofactors such as time, context, and biological circumstances.
Transmission: any mechanism by which an infectious disease is spread from a source to an individual. Violence can be transmitted horizontally, from individual to individual, and vertically, through intergenerational transmission.
Vector: carrier that transmits an infectious agent from one host to another.