Defining the term Micro-organism in the context of the Human Pathogens and Toxins Act

This Statement of Administrative Intent is intended to clarify the definition of micro-organism within the scope of the Human Pathogens and Toxins Act (HPTA).

  1. Definition of a Micro-organism

    A human pathogen is defined in section 3 of the HPTA as "a micro-organism, nucleic acid or protein that, (a) is listed in any of Schedules 2 to 4 or in Part 2 of Schedule 5; or (b) is not listed in any of the Schedules but falls into Risk Group 2, Risk Group 3 or Risk Group 4."

    The term micro-organism is not defined within the HPTA, but they are generally defined as an organism that is too small to be visible to the naked eye (i.e., microscopic), including bacteria, fungi, protists, protozoa, microalgae and, in the context of the HPTA, viruses.

    Organisms with multiple stages of development, such as helminths, may fit within the definition of a micro-organism during some developmental stages (e.g., eggs or larvae) but not others (e.g., adult form).

    • For the purpose of the HPTA, micro-organism means any organism that cannot be reasonably detected by the naked human eye, where reasonably detected means:
      1. any dimension of the organism is less than 100 μm; or
      2. all dimensions of the organism are more than 100 μm, but the organism can only be seen under ideal conditions of lighting and/or contrasting surface.
  2. When is a Micro-organism a Human Pathogen?
    • If the micro-organism meets the definition of a Risk Group 2, Risk Group 3 or Risk Group 4 human pathogen, then it is considered a human pathogen.
    • If the micro-organism is not listed in any of the Schedules to the HPTA, and it is unclear whether it meets the definition of Risk Group 2, Risk Group 3 or Risk Group 4 human pathogen, then a risk assessment should be conducted and the Agency should be consulted.
      • Note that the risk assessment should be more precautionary as the level of potential risk increases.
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