Tools - Belgian classification for micro-organisms based on their biological risks

(Note: cette page n'existe qu'en anglais - Nota: deze pagina bestaat enkel in het Engels)



In Belgium, all installations performing contained use activities involving human, animal or plant pathogens and their genetically engineered derivatives are subjected to regulatory provisions aiming at avoiding adverse effects on human health and the environment which might arise from the contained use of these micro-organisms.

To this end any user shall carry out an assessment of each contained use as regards the risks to human health and the environment that these contained uses may incur. The first stage in this assessment process is the identification of inherent harmful properties of the natural micro-organism.

In order to obtain the necessary information to implement this process the user may refer to classification lists (see table below).

These lists concern natural micro-organisms. They give the inherent risk of a pathogen and are based on the ability of the micro-organism to cause disease to humans, animals or plants on the basis of such factors as the severity of the disease it causes, the routes of infection, its virulence and infectivity. Other aspects such as the existence of effective therapies, possible effects on other species or possible environmental effects can also be taken into account.

> Criteria for the classification

The Regional decrees classify human and animal pathogens into three classes of risk and plant pathogens into two classes of risk.

> Definitions of classes of biological risk

The classification lists published in the Regional decrees were established in 1998 taking into account relevant Community legislation, international or national classification schemes as well as relevant scientific publications (see international classifications).

As a consequence of the evolution of scientific knowledge these lists are periodically revised for taxonomy and biological risk class, as well as supplemented with what is frequently notified in the framework of the legislation of contained use of GMO’s or pathogens in Belgium . The nomenclature of classified micro-organisms used to establish these lists reflects and is in conformity with the latest international agreements of the taxonomy and nomenclature of micro-organisms.
The revised lists are representative of pathogenic organisms that are prevalent or used for contained use activities in Belgium. Quarantine pests are no part of the revised lists. A recent list of quarantine organisms is available in annex of the Regulation (EU) 2019/2072 and Regulation (EU) 2019/1702.
It should be noted that micro-organisms which have not been classified for inclusion in classes of risk 2 to 4 of the lists are not implicitly classified in class 1.

As these revised classification lists provide updated information on pathogenic organisms, the user is advised to consult these revised lists for performing a risk assessment in the frame of the contained use legislation.

The revised classification lists are accompanied by an introductive note, explaining more in detail the methodology that has been used to establish the revised lists.

> Methodology used for revision of classification lists

Revised lists of pathogens and their corresponding class of biological risk

WARNING: The users must contact the Service of Biosafety and Biotechnology for any question relating to the classification and in particular for that of natural micro-organisms which would not appear in the lists. They can already use and complete the following form (only available in French or Dutch) which allows to gather the information available and necessary for the classification.

Human and animal pathogens

Plant pathogens


Please note that the biological risk class of some micro-organisms has been recently reviewed by the SBB taking into account the evolution of the classification list of human pathogenic micro-organisms of the Belgian federal legislation on the protection of workers, BOOK VII Biological agents (NL/FR), and the evolution of scientific knowledge.

The SBB is preparing a new general update of all the classification lists published in 2008 on its website. In the meantime, the following risk classes should be considered for risk assessment and management of contained use activities in Belgium:

  • Polio virus type 2 : Class of risk 3 for human
  • Kluyveromyces marxianus downscaled to class of risk 1, with the caution that it may cause disease in immunocompromised people and/or animals, newborns (0-3 months) and/or in the context of a hospital intervention (nosocomial infection), so-called opportunistic organisms. A deliberate activity with opportunistic organisms is not subject to notification under the regional contained use legislation, unless they are genetically modified.
  • Heterodera glycines downscaled to class of risk 2 for plant (31/01/2023)

  • Hepatitis E virus downscaled to class of risk 2 for human conform legislation Codex on well-being at work (Book VII) (07/02/2023)


As mentioned before, classification of a micro-organism on the basis of its biological risk is only a first step in the risk assessment. It gives only a provisional indication of the level of risk of the activity and the corresponding set of containment and other protective measures. It should be followed by a thorough consideration of how the micro-organism is to be manipulated.
Factors to be considered in determining the level of containment include:

  • the characteristics of the environment likely to be exposed (e.g. whether in the environment likely to be exposed to the micro-organism there are known hosts or biota which can be adversely affected by the micro-organism used in the contained use activity);
  • the characteristics of the activity (e.g. its scale, nature, the concentration of the micro-organism);
  • any non-standard operations (e.g. the inoculation of animals with pathogens; equipment likely to generate aerosols);
  • previous cases of laboratory acquired infection;
  • local availability of effective prophylaxis or therapeutic interventions.

A final assessment of risk based on all these considerations is therefore used to set the appropriate containment conditions for the experiment.  The containment level required may be equivalent to the risk classification of the micro-organism or it may be raised or lowered as a result of the above considerations.
Elements to be considered and the procedure to be followed to perform the full risk assessment are referred to in Annex III of the regional Decrees (see above).

 > Frequently Asked Questions (available soon)

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