Biomedical Engineering Reference
In-Depth Information
laboratory manipulations of each of these agents can be
safely conducted using good laboratory practices, barrier
precautions (gloves, gowns), and containment equipment
(Class II biological safety cabinets) recommended for
Animal Biosafety Level 2. In the absence of any demon-
strated aerosol infection hazard, no safety advantage is
gained by working with these agents using the additional
physical
involving infected laboratory animals, potentially and
known infected, as well as naturally and experimentally
infected. Descriptions regarding standard practices,
special practices, containment equipment, and animal
facilities are detailed in Biosafety in Microbiological and
Biomedical Laboratories (
Centers for Disease Control/
National Institutes of Health, 2009
). This excellent
publication also classifies most known human pathogens
according to the biosafety level and provides agent
summary statements.
Animal Biosafety Level 1 involves work with viable
microorganisms not known to cause disease in healthy
adult humans. Animal Biosafety Level 4 involves
dangerous and exotic agents that pose a high individual risk
of life-threatening disease (
Table 18.3
). Thus, most
nonhuman primate care and use must be conducted
according to recommendations for Animal Biosafety
Levels 2 and 3, which we have specified in detail from the
2009 CDC/NIH publication as follows.
containment
constraints
recommended for
Animal Biosafety Level 3.
Animal Biosafety Levels
Four biosafety levels are commonly referred to in working
with nonhuman primates and are designated as Animal
Biosafety Levels (ABSL) 1, 2, 3, and 4 and correspond
very closely to Biosafety Levels (BSL) 1, 2, 3, and 4 for
laboratories. These four combinations provide increasing
levels of protection to personnel and the environment and
are recommended as minimal standards for activities
TABLE 18.3
Summary of Recommended Biosafety Levels for Infectious Agents
Primary Barriers and
Safety Equipment
Facilities (Secondary
Barriers)
BSL
Agents
Practices
1
Not known to consistently
cause diseases in healthy
adults
Standard microbiological
practices
None required
Laboratory bench and sink
required
2
Agents associated with
human disease
Routes of transmission
include percutaneous
injury, ingestion, mucous
membrane exposure
BSL-1 practice plus:
Limited access
Biohazard warning signs
“Sharps” precautions
Biosafety manual defining
any needed waste
decontamination or medical
surveillance policies
Primary barriers:
Class I 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
transmission
Disease may have serious or
lethal consequences
BSL-2 practice plus:
Controlled access
Decontamination of all
waste
Decontamination of
laboratory clothing before
laundering
Baseline serum
Primary barriers:
Class I or II BSCs or other
physical containment
devices used for all open
manipulation of agents
PPEs:
Protective laboratory
clothing; gloves; respiratory
protection as needed
BSL-2 plus:
Physical separation from
access corridors
Self-closing, double-door
access
Exhaust air not recirculated
Negative airflow into
laboratory
4
Dangerous/exotic agents
which pose high risk of life-
threatening disease
Aerosol-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 facility
Primary barriers:
All procedures conducted in
Class III BSCs or Class I or II
BSCs in combination with
full-body, air-supplied,
positive pressure personnel
suit
BSL-3 plus:
Separate building or isolated
zone
Dedicated supply and
exhaust, vacuum, and
decontamination systems
Other requirements
outlined in the text
