Biosafety risk groups

Risk Groups

Risk Group 1 (RG1): Low individual and community risk

• Those capable of causing disease are considered pathogens that pose a low risk to the health of individuals or animals, and a low risk to public health or animal populations.
• A microorganism, nucleic acid, or protein that is either a) not capable of causing human or animal disease; or b) capable of causing human or animal disease, but unlikely to do so.
• May be opportunistic in immunocompromised individuals.
• Examples: Saccharomyces cerevisiae, Lactobacillus acidophilus

Risk Group 2 (RG2): Moderate individual risk and low community risk

• A pathogen that poses a moderate risk to the health of individuals or animals, and a low risk to public health or animal populations.
• These pathogens are able to cause serious disease in a human or animal but are unlikely to do so. Effective treatment and preventative measures are available and the risk of spread of diseases caused by these pathogens is low.
• It is important to remember that the definition assumes that an individual/animal is not immunocompromised (e.g., immune system is weakened by disease or treatment). For such individuals, these agents may be able to cause serious disease and even death. If your immune system is compromised by a cold or if you are pregnant, additional safety considerations may be required.
• Examples: Listeria monocytogenes, Campylobacter jejuni, Hepatitis A virus, Hepatitis B virus, Norwalk virus

Risk Group 3 (RG3): High individual risk and low community risk

• A pathogen that poses a high risk to the health of individuals or animals and a low risk to public health.
• These pathogens are likely to cause serious disease in a human or animal. Effective treatment and preventive measures are usually available and the risk of spread of disease caused by these pathogens is low for the public. The risk of spread to the animal population, however, can range from low to high depending on the pathogen.
• Examples: Yersinia pestis, Mycobacterium tuberculosis, Rabies virus, Severe acute respiratory syndrome (SARS) associated coronavirus

Risk Group 4 (RG4): High individual risk and high community risk

• A pathogen that poses a high risk to the health of individuals or animals and a high risk to public health.
• These pathogens are likely to cause serious disease in a human or animal, which can often lead to death. Effective treatment and preventive measures are not usually available and the risk of spread of disease caused by these pathogens is high for the public. The risk of spread of disease to the animal population, however, ranges from low to high depending on the pathogen.
• Examples: Ebola virus, Marburg virus, Herpes B virus

Containment Laboratories

• Containment levels similarly range from CL1 to CL4
• In general, the RG equals the CL required to handle the pathogen
• Factors to consider
  • Aerosol generation
  • Quantity
  • Concentration of pathogen: e.g. pure cultures (high concentration) compared to diagnostic specimens (low concentration)
  • Type of proposed work: e.g. type of animal required to study the pathogen
  • Shedding (of animals)

Containment Level 1 (CL1)

• Basic lab seen in any school
• No special features required except for a well-designed and functional space with cleanable work surfaces
  • Biological safety cabinets (BSCs) not required
• Must have appropriate PPE available, keep the lab clean, and decontaminate work surfaces

Containment Level 2 (CL2)

• Includes diagnostic healthcare laboraties and many university labs
• Primarily for RG2 that are not airborne-transmissable
• May need to follow agriculture requirements if housing animals (CL2-Ag)
• Require BSCs
• Need administrative controls and well-defined procedures

Containment Level 3 (CL3)

• More isolation required
  • Sealed windows
  • Use of a BSC for all work with open vessels
  • Inward-directional airflow
  • HEPA filtration of exhaust air
  • Strictly controlled lab access
• Requires higher-level operational practices
  • PPE with designated clean and dirty change areas
  • Decontamination of clothes before removing it
• Most of Canada's 100 CL3 labs are research-oriented

Containment Level 4 (CL4)

• Maximum containment
  • Complete seal of facility perimeter verified by pressure decay testing
  • Windows as well as plumbing and electrical conduits are sealed
  • Full-coverage positive-pressure suit with dedicated breathing supply, or working with samples in isolated, sealed BSC using long-sleeved gloves
  • Decontamination of effluents, including HEPA filtration of all supply and exhaust air
• Full-coverage PPE must be decontaminated with a chemical shower
• Only two labs in Canada, one for human pathogens and the other for animal pathogens

Further Reading

• Health Canada ePathogens database of risk groups
• Health Canada Pathogen Safety Data Sheets (PSDSs)