Epidemiology and the Chain of Infection

A set of flashcards covering key vocabulary terms and definitions related to epidemiology and the chain of infection.

Chain of Infection

The series of steps involved in the spread of disease-causing pathogens from one host to another.

Reservoir

A natural host or habitat where a pathogen lives and multiplies.

Zoonoses

Diseases that are transmitted from animals to humans.

Portals of Exit

Routes through which a pathogen exits the body, including respiratory secretions, feces, and skin.

Vertical Transmission

Transmission of infection from a pregnant woman to her fetus or from mother to infant during childbirth.

Horizontal Transmission

Transmission of infection from person to person through air, contact, ingestion, or via vectors.

Direct Transmission

Immediate transfer of an infectious agent to a portal of entry.

Indirect Transmission

Transmission of a pathogen through an intermediary, such as a vehicle or vector.

Fomites

Inanimate objects that can carry pathogens.

Vector-borne Transmission

Transmission of an infectious agent by living organisms (vectors) such as insects.

R0 (Reproduction number)

A measure of the contagiousness of an infectious disease in a completely susceptible population.

Localized Infection

An infection that is confined to a specific area of the body.

Systemic Infection

An infection that spreads throughout the body, affecting multiple systems.

Herd Immunity

Immunity in a population that protects individuals who are not immune by reducing the overall presence of the pathogen.

Antigenic Variation

The ability of an infectious agent to change its surface proteins to evade the immune response.

Factors influencing Epidemiology

Elements such as host population immunity, general health, and genetic background that impact disease spread.