1.3 Key surveillance terms

• Data – This term refers to a set of observations or measurements relating to a particular entity. An entity, in keeping with the ‘public health’ scope of this module, can be an individual, for example, a hospital patient or a bacterial isolate. Data can be processed or unprocessed and represented as text, numbers or multimedia. A more detailed discussion around this term is provided in the module Fundamentals of data for AMR.
• Dataset – A dataset is a structured collection of data, usually taking the form of a table with rows and columns. A more detailed discussion around this term is provided in the module Fundamentals of data for AMR.
• Database – A database is an organised collection of multiple datasets. Databases are generally hosted on a computer network, allowing for easy access and manipulation.
• Infection – Refers to a state of disease which occurs when a foreign pathogenic organism, for example, a bacterium, enters the body, multiplies and causes the host harm.
• Bacterial infection – When an infection is caused by bacteria.
• Carriage – A state when a person (or animal) harbours a specific infectious agent without discernible symptoms of disease. The infectious agent lives on some specific surface of the body or somewhere inside the body (the niche). This ‘carriage state’ serves as a potential source of infection, either to the individual themselves or following transmission to another individual. Carriage may exist in an individual with an infection that is not apparent throughout its course, known as inapparent. This individual is commonly referred to as healthy or asymptomatic carrier.
• Healthcare-associated infection – An infection acquired by a patient while in a hospital or healthcare facility, in whom it was not present or incubating at the time of admission to the facility. Healthcare-associated infections are also referred to as nosocomial infections.
• Community-associated infection – An infection occurring in an individual contracted outside of a hospital or healthcare facility. For a patient admitted to hospital, it is assumed that any infection occurring within 48 hours of admission has been acquired in the community.
• Healthcare facility – Generally refers to a location where healthcare is provided, for example, a hospital or clinic, or a veterinary clinic or hospital.
• Incidence – The number of new cases of a specified disease diagnosed or reported during a defined period of time. When this number of new cases is divided by the number of persons in a stated population in which the cases occurred, it gives you the incidence rate. This is usually expressed as cases per 1000 or 100,000 population.
• Prevalence – The total number of persons (or animals) sick or exhibiting symptoms of a certain condition in a stated population at a particular time (point prevalence), or during a stated period of time (period prevalence), regardless of when that illness or condition began. When this number is divided by the population at risk of having the disease or condition at the point in time (or midway through the period in which it occurred), it gives you the prevalence rate.