This glossary was created with input from members of PICNet, PHAC Infection Control Guidelines and the BC Ministry of Health. A list of references is available here. Definitions will be updated frequently and may change or be removed. Please send us your comments and feedback by email to picnet@phsa.ca.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Decontamination: The removal of disease-producing microorganisms to leave an item safe for further handling (7).

Denominator: The lower portion of a fraction, used to calculate a rate or ratio. The population (or population experience, as in person-years, passenger miles, etc.) at risk in the calculation of a rate or a ratio. Valid information on denominators is essential in clinical and epidemiological research and also in many public health activities. (17)

Disease: Clinical expression of infection; signs and/or symptoms are produced (9).

Disinfection: The inactivation of disease-producing microorganisms. Disinfection does not destroy bacterial spores. Disinfection usually involves chemicals, heat or ultraviolet light. (8, 17).

Disorder: A disturbance or departure from normal health function.

Disease: A disorder that can be assigned to a diagnostic category; it usually has a distinct clinical course and usually a distinct etiology. (11)

Droplet Transmission: Transmission occurs from droplets that are equal to or over five microns in diameter, generated from the respiratory tract of the source patient during coughing or sneezing or some procedures such as suctioning or bronchoscopy. These droplets are propelled a short distance, <2 meters, through the air. An infection is spread when droplets of contaminated respiratory secretions come into direct contact with the mucous membranes of the mouth, nose and possibly eyes of another person. (9)

Droplet Transmission Precautions: Measures to reduce the risk of droplet transmission of infectious agents (6).

Droplet Nuclei: a type of particle implicated in the spread of airborne infection. Droplet nuclei are tiny particles (1-10µm diameter) that represent the dried residue of droplets. They may be formed by 1) evaporation of droplets coughed or sneezed into the air or 2) aerosolization of infective materials. (11)

Drug Identification number (DIN): In Canada, disinfectants are regulated under the Food and Drugs Act and Regulations. Disinfectants must have a drug identification number (DIN) from Health Canada prior to marketing. This ensures that labeling and supportive data have been provided and that it has been established by the Therapeutic Drugs Dictorate that the product is effective and safe for its intended use. (13)