Biomedical Engineering Reference
In-Depth Information
minimize the accumulation of debris or fomites. Floor
drains must be maintained and filled with water, and/or
appropriate disinfectant to prevent the migration of
vermin and gases.
8.
Cages are washed in a mechanical cage washer. The
mechanical cage washer has a final rinse temperature
of at least 180
F. Cages should be autoclaved or
otherwise decontaminated prior to removal from
ABSL-3 space. The cage wash facility should be
designed and constructed to accommodate high pres-
sure spray systems, humidity, strong chemical disin-
fectants, and 180
F water temperatures, during the
cage cleaning process.
9.
BSCs (Class II, Class III) must be installed so that
fluctuations of the room air supply and exhaust do not
interfere with its proper operations. Class II BSCs
should be located away from doors, heavily traveled
laboratory areas, and other possible airflow disrup-
tions. HEPA filtered exhaust air from a Class II BSC
can be safely re-circulated back into the laboratory
environment if the cabinet is tested and certified at
least annually and operated according to manufac-
turer's recommendations. BSCs can also be connected
to the laboratory exhaust system by either a thimble
(canopy) connection or a direct (hard) connection.
Provisions to assure proper safety cabinet performance
and air system operation must be verified. BSCs
should be certified at least annually to assure correct
performance. Class III BSCs must supply air in such
a manner that prevents positive pressurization of the
cabinet or the laboratory room. All BSCs should be
used according to manufacturers' recommendations.
When applicable, equipment that may produce infec-
tious aerosols must be contained in devices that
exhaust air through HEPA filtration or other equivalent
technology before being discharged into the animal
facility. These HEPA filters should be tested and/or
replaced at least annually.
10.
An autoclave is available which is convenient to the
animal rooms where the biohazard is contained. The
autoclave is utilized to decontaminate infectious mate-
rials and waste before moving it to the other areas of the
facility. If not convenient to areas where infectious
materials and/or animals are housed or are manipulated,
special practices should be developed for transport of
infectious materials designated alternate location/s
within the facility. Vacuum lines must be protected with
HEPA filters, or their equivalent. Filters must be
replaced as needed. Liquid disinfectant traps may be
required. Emergency eyewash and shower are readily
available; location is determined by risk assessment.
11.
The ABSL-3 facility design and operational proce-
dures must be documented. The facility must be tested
to verify that the design and operational parameters
have been met prior to use. Facilities should be re-
verified at least annually against these procedures as
modified by operational experience. Additional envi-
ronmental protection (e.g. personnel showers, HEPA
filtration of exhaust air, containment of other piped
services, and the provision or effluent decontamina-
tion) should be considered if recommended by the
agent summary statement, as determined by risk
assessment of the site conditions, or other applicable
federal, state or local regulations.
Universal and Enteric Precautions
The CDC established the strategy of universal protection
fromblood and body fluids to address concerns regarding the
transmission of HIV in the healthcare setting (
Antiterrorism
and Effective Death Penalty Act, 1996
). These guidelines,
referred to as “universal precautions,” are based on the
concept that all patients should be assumed to be infectious
for HIV and other bloodborne pathogens. Since a similar
assumption ismadewhenworkingwith nonhuman primates,
these universal precautions should be followed when
workers are exposed to nonhuman primate blood, or other
body fluids (saliva, amniotic fluid, pericardial fluid, perito-
neal fluid, pleural fluid, synovial fluid, cerebrospinal fluid,
semen, and vaginal secretions), and, particularly, any body
fluid visibly contaminated with blood.
The modes of transmission of HBVand HIVare similar,
and in occupational settings blood is the single most
important source of HIV and HBV. Both viruses have been
transmitted only by percutaneous inoculation or contact
with open wounds, nonintact (e.g. chapped, abraded,
weeping, or dermatologic) skin, or mucous membranes with
blood, blood-contaminated body fluids, or concentrated
virus. Since HIV and HBV transmission has not been
documented from exposure to other body fluids (feces, nasal
secretions, sputum, sweat, tears, urine, and vomitus), the
CDC does not apply “universal precautions” to these fluids.
Universal precautions apply to saliva only in the dental
setting, where it is likely to be contaminated with blood
(
Centers for Disease Control, 1985
). However, trans-
mission of HBV to gibbons and of non-A, non-B hepatitis
(NANBH) to chimpanzees by saliva has been reported
(
Abe et al., 1987
); saliva is the major vehicle for the spread
of herpes B virus infection, so universal precautions
should be observed for all contact work with all nonhuman
primates.
General universal precautions address such topics as
training and competence, vaccines and other prophylaxis,
appropriate protective clothing, the necessity and value of
hand washing, and the proper disposition of sharps. These
topics are covered elsewhere in this chapter.
