Animal Biosafety Levels

Summary of Recommended Biosafety Levels for Activities Using Experimentally or Naturally Infected Animals

ABSL Agents Practices Safety Equipment (Primary Barriers) Facilities (Secondary Barriers)
1 Not known to consistently cause disease in healthy human adults Standard animal care and management practices, including appropriate medical surveillance programs As required for normal care of each species Standard facility
No recirculation of exhaust air
Directional airflow recommended
Hand washing sink recommended
2 Associated with human disease.
Hazard: percutaneous exposure, ingestion, mucus membrane exposure
ABSL-1 practices plus:

– Limited access

– Biohazard warning signs

– “Sharps” precautions

– Biosafety manual

–  Decontamination of all infectious wastes and of animal cages prior to washing

ABSL-1 equipment plus primary barriers:Containment equipment appropriate for animal species; PPEs:Laboratory coats, gloves, face and respiratory protection as needed ABSL-1 facility plus:
Autoclave available
Hand washing sink available in the animal room
Mechanical cage washer used
3 Indigenous or exotic agents with potential for aerosol transmissionDisease may have serious health effects. ABSL-2 practices plus:

– Controlled access

– Decontamination of clothing before laundering

– Cage decontaminated before bedding removed

– Disinfectant footbath as needed

ABSL-2 equipment plus:
Containment equipment for housing animals and cage dumping activitiesClass I or II BSCs available for manipulative procedures (inoculation, necropsy) that may cause infectious aerosols. PPEs:Appropriate respiratory protection
ABSL-2 facility plus:
Physical separation from access corridors
Self-closing double door access
Sealed penetrations
Sealed windows
Autoclave available in facility
4 Dangerous/exotic agents that pose high risk of life threatening diseaseAaerosol transmission, or related agents with unknown risk of transmission. ABSL-3 practices plus:- Entrance through change room where personal clothing is removed and laboratory clothing is put on; shower on exiting- All wastes are decontaminated before removal from the facility ABSL-3 equipment plus:Maximum containment equipment (i.e. Class III BSC or partial containment equipment in combination with full body, air supplied positive-pressure personnel suit) used for all procedures and activities ABSL-3 facility plus:Separate building or isolated zone
Dedicated supply and exhaust, vacuum and decontamination systems
Other requirements as explained in the text (book)

 

Biosafety Levels

Summary of Recommended Biosafety Levels for Infectious Agents

BSL Agents Practices Safety Equipment (Primary Barriers) Facilities (Secondary Barriers)
1 Not known to consistently cause disease in healthy human adults Standard Microbiological practices None required Open bench top sink required
2 Associated with human disease.Routes of transmission include percutaneous injury, ingestion, mucus membrane exposure BSL-1 practices plus:- Limited access- Biohazard warning signs

– “Sharps” precautions

– Biosafety manual defining any needed waste decontamination or medical surveillance policies

Primary barriers:Class 1 or II BSCs or other physical containment devices used for all manipulations of agents that cause splashes or aerosols of infectious materials; PPEs:Laboratory coats, gloves, face protection as needed BSL-1 plus:
Autoclave available
3 Indigenous or exotic agents with potential for aerosol transmissionDisease may have serious health effects. BSL-2 practices plus:- Controlled access- Decontamination of all waste

– Decontamination of lab clothing before laundering

– Baseline serum

Primary barriers:Class 1 or II BSCs or other physical containment devices used for all manipulations of agentsPPEs: Protective laboratory clothing, gloves, respiratory protection as needed BSL-2 plus:- Physical separation from access corridors
– Self-closing double door access- Exhausted air not recirculated- Negative airflow into laboratory
4 Dangerous/exotic agents that pose high risk of life threatening diseaseAerosol transmitted laboratory infections have occurred, or related agents with unknown risk of transmission. BSL-3 practices plus:>- Clothing change before entering- Shower on exit

– All material decontaminated on exit from the facility

Primary barriers:All procedures conducted in Class III BSC or Class I or II BSCs in combination with full body, air supplied positive-pressure personnel suit. BSL-3 facility plus:- Separate building or isolated zone- Dedicated supply and exhaust, vacuum and decontamination systems

– Other requirements as explained in the text (book)


From Biosafety in Mircobiological and Biomedical Laboratories, US Department of Health and Human Services, Public Health Service, CDC and NIH, 5th edition, 2007.

BSL = Biosafety Level; ABSL = Animal Biosafety Level; PPE = Personal protective equipment; BSC = Biosafety cabinet.

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