Agent Summary Statement for Human Immunodeficiency Viruses
(HIVs) Including HTLV-III, LAV, HIV-1, and HIV-2*
INTRODUCTION
In 1984, the Centers for Disease Control (CDC) and the National
Institutes of Health (NIH), in consultation with experts from
academic institutions, industry, and government, published the
book Biosafety in Microbiological and Biomedical Laboratories
("Guidelines")** (1).
These Guidelines are based on combinations of standard and
special practices, equipment, and facilities recommended for use
in working with infectious agents in various laboratory settings.
The recommendations are advisory; they provide a general code for
operating microbiologic and biomedical laboratories.
One section of the Guidelines is devoted to standard and
special microbiologic practices, safety equipment, and facilities
for biosafety levels (BSL) 1 through 4. Another section contains
specific agent summary statements, each consisting of a brief
description of laboratory-associated infections, the nature of
laboratory hazards, and recommended precautions for working with
the causative agent. The authors realized that the discovery of
the availability of information about these agents would
necessitate updating the agent summary. Such a statement for
human immunodeficiency virus (HIV) (called HTLV-III/LAV when the
Guidelines were published) was published in MMWR in 1986 (2). The
HIV agent summary statement printed in this Supplement updates
the 1986 statement.
Attached to the updated HIV agent summary statement are the
essential elements for BSL 2 and 3 laboratories, reproduced from
the Guidelines (1) (see Addendum 1, p. 6). BSL 2 and 3 laboratory
descriptions are included because they are recommended for
laboratory personnel working with HIV, depending on the
concentration or quantity of virus or the type of laboratory
procedures used.
The HIV agent summary statement does not specifically address
safety measures for collecting and handling clinical specimens.
Nonetheless, it has been recommended that blood and body-fluid
precautions consistently be used for ALL specimens from ALL
patients. This approach, referred to as "universal blood and
body- fluid precautions" or "universal precautions," eliminates
the need to identify all patients infected with HIV (or other
bloodborne pathogens) (3). This subject is also covered in other
publications (3-8).
Laboratory directors, supervisors, and others are asked to
attach a copy of this revised "1988 Agent Summary Statement for
Human Immunodeficiency Virus" to each copy of the Guidelines and
to all copies of their laboratory biosafety manual; they should
review the recommended precautions with laboratory personnel,
provide appropriate training in practices and operation of
facilities, and ensure that all personnel demonstrate proficiency
BEFORE being allowed to work with HIV. The laboratory director
(or the designated laboratory supervisor) is responsible for
biosafety in the laboratory and must establish and implement
practices, facilities, equipment, training, and work assignments
as appropriate (9).
HIV AGENT SUMMARY STATEMENT
Agent: HIVs Including HTLV-III, LAV, HIV-1, and HIV-2
In the period 1984-1986, several health-care workers (HCWs) who
had no recognized risk behavior for acquired immunodeficiency
syndrome (AIDS) were reported to have HIV infection (10-15). Only
one of these HCWs was identified as a laboratory worker. These
and other reports assessed the risk of work-related HIV infection
for all HCWs as being very low (3,6,10-12,14-18).
In 1985, anecdotal reports were received indicating that
workers in two different HIV-reagent-production laboratories had
been exposed to droplets and splashed liquid from a vessel
containing concentrated virus. One of several workers had been
cut by glass from a broken carboy that contained HIV-infected
cells and medium. None of the persons exposed in these episodes
had developed antibody to HIV or had clinical signs of infection
18 and 20 months, respectively, after the reported exposure.
In 1987, CDC received reports that three HCWs had HIV
infection; none of the infections were associated with
needlesticks or cuts. Two of these HCWs were clinical laboratory
workers (11). One was a phlebotomist whose face and mouth were
splattered with a patient's blood when the rubber stopper was
suddenly expelled from a blood-collection tube. The second was a
medical technologist who inadver- tently spilled blood on her
arms and forearms while using an apheresis apparatus to process
blood from an HIV-seropositive patient.
In September 1987, a production-laboratory worker was reported
to have HIV infection (18). This person worked with large
concentrations of HIV in a BSL 3 facility. HIV was isolated from
the worker's blood; the isolate was genetically indistinguishable
from the strain of virus being cultivated in the laboratory. No
risk factors were identified, and the worker recalled no specific
incident that might have led to infection. However, there were
instances of leakage of virus-positive culture fluid from
equipment and contamination of the work area and centrifuge
rotors. The report concluded that the most plausible source of
exposure was contact of the worker's gloved hand with
virus-culture supernatant, followed by inapparent exposure to
skin.
In October 1987, a second person who worked in another HIV
production facility was reported to have HIV infection (18). This
laboratory was a well-equipped BSL 3 facility, and BSL 3
practices were being followed. This worker reported having
sustained a puncture wound to a finger while cleaning equipment
used to concentrate HIV.
Laboratory Hazards
HIV has been isolated from blood, semen, saliva, tears, urine,
cerebrospinal fluid, amniotic fluid, breast milk, cervical
secretions, and tissue of infected persons and experimentally
infected nonhuman primates. In the laboratory, virus should be
presumed to be present in all HIV cultures, in all materials
derived from HIV cultures, and in/on all equipment and devices
coming into direct contact with any of these materials.
In the laboratory, the skin (especially when scratches, cuts,
abrasions, dermatitis, or other lesions are present) and mucous
membranes of the eye, nose, mouth, and possibly the respiratory
tract should be considered as potential pathways for entry of
virus. Needles, sharp instruments, broken glass, and other sharp
objects must be carefully handled and properly discarded. Care
must be taken to avoid spilling and splashing infected
cell-culture liquid and other virus-containing materials.
Recommended Precautions
BSL 2 standards and special practices, containment
equipment, and facilities, as described in the CDC-NIH
publication Biosafety in Microbiological and Biomedical
Laboratories (Guidelines), are recommended for activities
involving all clinical specimens, body fluids, and tissues
from humans or from infected or inoculated laboratory
animals. These are the same standards and practices
recommended for handling all clinical specimens. For
example, and for emphasis:
Use of syringes, needles, and other sharp instruments
should be avoided if possible. Used needles and disposable
cutting instruments should be discarded into a
puncture-resistant container with a lid. Needles should not
be re-sheathed, bent, broken, removed from disposable
syringes, or otherwise manipulated by hand.
Protective gloves should be worn by all personnel engaged
in activities that may involve direct contact of skin with
potentially infectious specimens, cultures, or tissues.
Gloves should be carefully removed and changed when they
are visibly contaminated. Personnel who have dermatitis or
other lesions on the hands and who may have indirect
contact with potentially infectious material should also
wear protective gloves. Hand washing with soap and water
immediately after infectious materials are handled and
after work is completed--EVEN WHEN GLOVES HAVE BEEN WORN as
described above--should be a routine practice.
Generation of aerosols, droplets, splashes, and spills
should be avoided. A biological safety cabinet should be
used for all procedures that might generate aerosols or
droplets and for all infected cell-culture manipulations.
The Guidelines (pp. 11-13) contain additional precautions
for operating at BSL 2.
2. Activities such as producing research-laboratory-scale
amounts of HIV, manipulating concentrated virus
preparations, and conducting procedures that may produce
aerosols or droplets should be performed in a BSL 2
facility with the additional practices and containment
equipment recommended for BSL 3 (19) (Guidelines, pp.
14-17).
3. Activities involving industrial-scale, large-volume
production or high concentration and manipulation of
concentrated HIV should be conducted in a BSL 3 facility
using BSL 3 practices and equipment (19).
4. BSL 2 practices, containment equipment, and facilities for
animals are recommended for activities involving nonhuman
primates and any animals experimentally infected or
inoculated with HIV. Because laboratory animals may bite,
throw feces or urine, or expectorate at humans, animal-care
personnel, investigators, technical staff, and other
persons who enter the animal rooms should wear coats,
protective gloves, coveralls or uniforms, and--as
appropriate--face shields or surgical masks and eye shields
to protect the skin and mucous membranes of the eyes, nose,
and mouth.
5. All laboratory glassware, disposable material, and waste
material suspected or known to contain HIV should be
decontaminated, preferably in an autoclave, before it is
washed, discarded, etc. An alternate method of disposing of
solid wastes is incineration.
6. Laboratory workers should wear laboratory coats, gowns, or
uniforms when working with HIV or with material known or
suspected to contain HIV. There is no evidence that
laboratory clothing poses a risk for HIV transmission;
however, clothing that becomes contaminated with HIV
preparations should be decontaminated before being
laundered or discarded. Laboratory personnel must remove
laboratory clothing before going to nonlaboratory areas.
7. Work surfaces should be decontaminated with an appropriate
chemical germicide after procedures are completed, when
surfaces are overtly contaminated, and at the end of each
work day. Many commercially available chemical
disinfectants (5,20-23) can be used for decontaminating
laboratory work surfaces, for some laboratory instruments,
for spot cleaning of contaminated laboratory clothing, and
for spills of infectious materials. Prompt decontamination
of spills should be standard practice.
8. Universal precautions are recommended for handling all
human blood specimens for hematologic, microbiologic,
chemical, serologic testing; these are the same precautions
for preventing transmission of all bloodborne infections
including hepatitis B (17,21,24,25). It is not certain how
effective 56 C-60 C heat is in destroying HIV in serum
(22,23,26), but heating small volumes of serum for 30
minutes at 56 C before serologic testing reduces residual
infectivity to below detectable levels. Such treatment
causes some false-positive results in HIV enzyme
immunoassays (27-30) and may also affect some biochemical
assays performed on serum (27,31,32).
9. Human serum from any source that is used as a control or
reagent in a test procedure should be handled at BSL 2
(Guidelines, pp. 11-13). Addendum 2 (p. 16) to this report
is a statement issued by CDC on the use of all human
control and reagent serum specimens shipped to other
laboratories. The Food and Drug Administration requires
that manufacturers of human serum reagents use a similarly
worded statement.
10. Medical surveillance programs should be in place in all
laboratories that test specimens, do research, or produce
reagents involving HIV. The nature and scope of a
surveillance program will vary according to institutional
policy and applicable local, state, and Federal regulations
(9).
11. If a laboratory worker has a parenteral or mucous-membrane
exposure to blood, body fluid, or viral-culture material,
the source material should be identified and, if possible,
tested for the presence of virus. If the source material is
positive for HIV antibody, virus, or antigen, or is not
available for examination, the worker should be counseled
regarding the risk of infection and should be evaluated
clinically and serologically for evidence of HIV infection.
The worker should be advised to report on and to seek
medical evaluation of any acute febrile illness that occurs
within 12 weeks after the exposure (3). Such an
illness--particularly one characterized by fever, rash, or
lymphadenopathy--may indicate recent HIV infection. If
seronegative, the worker should be retested 6 weeks after
the exposure and periodically thereafter (e.g., at 12 weeks
and 6 months after exposure). During this follow-up
period--especially during the first 6-12 weeks after
exposure, when most infected persons are expected to show
serologic evidence of infection--exposed workers should be
counseled to follow Public Health Service recommendations
for preventing transmission of HIV (3,14,25,33). It is
recommended that all institutions establish written
policies regarding the management of laboratory exposure to
HIV; such policies should deal with confidentiality,
counseling, and other related issues.
12. Other primary and opportunistic pathogenic agents may be
present in the body fluids and tissues of persons infected
with HIV. Laboratory workers should follow accepted
biosafety practices to ensure maximum protection against
inadvertent laboratory exposure to agents that may also be
present in clinical specimens (34-36).
13. Unless otherwise dictated by institutional policy, the
laboratory director (or designated laboratory supervisor)
is responsible for carrying out the biosafety program in
the laboratory. In this regard, the laboratory director or
designated supervisor should establish the biosafety level
for each component of the work to be done and should ensure
that facilities and equipment are adequate and in good
working order, that appropriate initial and periodic
training is provided to the laboratory staff, and that
recommended practices and procedures are strictly followed
(9).
14. Attention is directed to a "Joint Advisory Notice" of the
Departments of Labor and Health and Human Services (9) that
describes the responsibility of employers to provide "safe
and healthful working conditions" to protect employees
against occupational infection with HIV. The notice defines
three exposure categories of generic job-related tasks and
describes the protective measures required for employees
involved in each exposure category. These measures are:
administrative measures, training and education programs
for employees, engineering controls, work practices,
medical and health-care practices, and record- keeping. The
recommendations in this report are consistent with the
"Joint Advisory Notice"; managers/directors of all
biomedical laboratories are urged to read this notice.
*The information and recommendations contained in this document
were developed and compiled by the Division of Safety, National
Institute of Allergy and Infectious Diseases, the National Cancer
Institute, and the Clinical Center of the National Institutes of
Health; Food and Drug Administration; and the following CDC
units: AIDS Program, Hospital Infections Program, Office of the
Director, Center for Infectious Diseases; the Training and
Laboratory Program Office; and the Office of Biosafety, Office of
the Centers Director; Representatives of the following
organizations also collaborated in the effort: the American
Academy of Microbiology, the American Biological Safety
Association, the American Society for Microbiology, the American
Society for Clinical Pathology, the Association of State and
Territorial Public Health Laboratory Directors, the College of
American Pathologists, the Pharmaceutical Manufacturers
Association, and the Walter Reed Army Institute for Research.
**Available from Superintendent of Documents, U.S. Government
Printing Office, Washington, DC 20402, Stock #01702300167-1; or
from National Technical Information Service, U.S. Department of
Commerce, 5285 Port Royal Road, Springfield, VA 22161, Stock
Biosafety Level 2 is similar to Level 1 and is suitable for
work involving agents that represent a moderate hazard for
personnel and the environment. It differs in that a) laboratory
personnel have specific training in handling pathogenic agents
and are directed by competent scientists, b) access to the
laboratory is limited when work is being conducted, and c)
certain procedures in which infectious aerosols are created are
conducted in biological safety cabinets or other physical
containment equipment.
The following standard and special practices, safety equipment,
and facilities apply to agents assigned to Biosafety Level 2:
Standard microbiological practices
Access to the laboratory is limited or restricted by the
laboratory director when work with infectious agents is in
progress.
Work surfaces are decontaminated at least once a day and after
any spill of viable material.
All Infectious liquid or solid waste is decontaminated before
being disposed of.
Mechanical pipetting devices are used; mouth pipetting is
prohibited.
Eating, drinking, smoking, and applying cosmetics are not
permitted in the work area. Food must be stored in cabinets or
refrigerators designed and used for this purpose only. Food
storage cabinets or refrigerators should be located outside the
work area.
Persons are to wash their hands when they leave the laboratory
after handling infectious material or animals.
All procedures are performed carefully to minimize the
creation of aerosols.
B. Special practices
Contaminated materials that are to be decontaminated away from
the laboratory are placed in a durable, leakproof container that
is closed before being removed from the laboratory.
The laboratory director limits access to the laboratory. In
general, persons who are at increased risk of acquiring infection
or for whom infection may be unusually hazardous are not allowed
in the laboratory or animal rooms. The director has the final
responsibility for assessing each circumstance and determining
who may enter or work in the laboratory.
The laboratory director establishes policies or procedures
whereby only persons who have been advised of the potential
hazard and who meet any specific entry requirements (e.g.,
vaccination) enter the laboratory or animal rooms.
When an infectious agent being worked with in the laboratory
requires special provisions for entry (e.g., vaccination), a
hazard warning sign that incorporates the universal biohazard
symbol is posted on the access door to the laboratory work area.
The hazard warning sign identifies the infectious agent, lists
the name and telephone number of the laboratory director or other
responsible person(s), and indicates the special requirement(s)
for entering the laboratory.
An insect and rodent control program is in effect.
Laboratory coats, gowns, smocks, or uniforms are worn while in
the laboratory. Before leaving the laboratory for nonlaboratory
areas (e.g., cafeteria, library, administrative offices), this
protective clothing is removed and left in the laboratory or
covered with a clean coat not used in the laboratory.
Animals not involved in the work being performed are not
permitted in the laboratory.
Special care is taken to avoid having skin be contaminated
with infectious material; gloves should be worn when handling
infected animals and when skin contact with infectious material
is unavoidable.
All waste from laboratories and animal rooms is appropriately
decontaminated before disposal.
Hypodermic needles and syringes are used only for parenteral
injection and aspiration of fluids from laboratory animals and
diaphragm bottles. Only needle-locking syringes or disposable
syringe-needle units (i.e., the needle is integral to the
syringe) are used for the injection or aspiration of infectious
fluid. Extreme caution should be used when handling needles and
syringes to avoid autoinoculation and the generation of aerosols
during use and disposal. A needle should not be bent, sheared,
replaced in the sheath or guard, or removed from the syringe
following use. The needle and syringe should be promptly placed
in a puncture-resistant container and decontaminated, preferably
by autoclaving, before discard or reuse.
Spills and accidents that result in overt exposures to
infectious material are immediately reported to the laboratory
director. Medical evaluation, surveillance, and treatment are
provided as appropriate, and written records are maintained.
When appropriate, considering the agent(s) handled, baseline
serum samples for laboratory and other at-risk personnel are
collected and stored. Additional serum specimens may be collected
periodically, depending on the agents handled or on the function
of the facility.
A biosafety manual is prepared or adopted. Personnel are
advised of special hazards and are required to read instructions
on practices and procedures and to follow them.
C. Containment equipment
Biological safety cabinets (Class I or II) or other appropriate
personal- protection or physical-containment devices are used
when:
Procedures with a high potential for creating infectious
aerosols are conducted. These may include centrifuging, grinding,
blending, vigorous shaking or mixing, sonic disruption, opening
containers of infectious materials whose internal pressures may
be different from ambient pressures, inoculating animals
intranasally, and harvesting infected tissues from animals or
eggs.
High concentrations or large volumes of infectious agents are
used. Some types of materials may be centrifuged in the open
laboratory if sealed heads or centrifuge safety cups are used and
if the containers are opened only in a biological safety cabinet.
D. Laboratory facilities
The laboratory is designed so that it can be easily cleaned.
Bench tops are impervious to water and resistant to acids,
alkalis, organic solvents, and moderate heat.
Laboratory furniture is sturdy, and spaces between benches,
cabinets, and equipment are accessible for cleaning.
Each laboratory contains a sink for hand washing.
If the laboratory has windows that open, they are fitted with
fly screens.
An autoclave for decontaminating infectious laboratory wastes
is available.
Biosafety Level 3
Biosafety Level 3 is applicable to clinical, diagnostic,
teaching, research, or production facilities in which work is
done with indigenous or exotic agents that may cause serious or
potentially lethal disease as a result of exposure by inhalation.
Laboratory personnel have specific training in handling
pathogenic and/or potentially lethal agents and are supervised by
competent scientists who are experienced in working with these
agents. All procedures involving the manipulation of infectious
material are conducted within biological safety cabinets or other
physical containment devices or by personnel wearing appropriate
personal-protection clothing and devices. The laboratory has
special engineering and design features. It is recognized,
however, that many existing facilities may not have all the
facility safeguards recommended for Biosafety Level 3 (e.g.,
access zone, sealed penetrations, and directional airflow). In
these circumstances, acceptable safety may be achieved for
routine or repetitive operations (e.g., diagnostic procedures
involving the propagation of an agent for identification, typing,
and susceptibility testing) in laboratories in which facility
features satisfy Biosafety Level 2 recommendations if the
recommended "Standard Microbiological Practices," "Special
Practices," and "Containment Equipment" for Biosafety Level 3 are
rigorously followed. The decision to implement this modification
of Biosafety Level 3 recommendations should be made only by the
laboratory director.
The following standard and special safety practices, equipment,
and facilities apply to agents assigned to Biosafety Level 3:
Standard microbiological practices
Work surfaces are decontaminated at least once a day and
after any spill of viable material.
All infectious liquid or solid waste is decontaminated
before being disposed of.
Mechanical pipetting devices are used; mouth pipetting is
prohibited.
Eating, drinking, smoking, storing food, and applying
cosmetics are not permitted in the work area.
Persons wash their hands after handling infectious
materials and animals and every time they leave the
laboratory.
All procedures are performed carefully to minimize the
creation of aerosols.
B. Special practices
Laboratory doors are kept closed when experiments are in
progress.
Contaminated materials that are to be decontaminated at a
site away from the laboratory are placed in a durable,
leakproof container that is closed before being removed
from the laboratory.
The laboratory director controls access to the laboratory
and limits access only to persons whose presence is
required for program or support purposes. Persons who are
at increased risk of acquiring infection or for whom
infection may be unusually hazardous are not allowed in the
laboratory or animal rooms. The director has the final
responsibility for assessing each circumstance and
determining who may enter or work in the laboratory.
The laboratory director establishes policies and procedures
whereby only persons who have been advised of the potential
biohazard, who meet any specific entry requirements (e.g.,
vaccination), and who comply with all entry and exit
procedures enter the laboratory or animal rooms.
When infectious materials or infected animals are present
in the laboratory or containment module, a hazard warning
sign (incorporating the universal biohazard symbol) is
posted on all laboratory and animal-room access doors. The
hazard warning sign identifies the agent, lists the name
and telephone number of the laboratory director or other
responsible person(s), and indicates any special
requirements for entering the laboratory, such as the need
for vaccinations, respirators, or other personal-protection
measures.
All activities involving infectious materials are conducted
in biological safety cabinets or other physical-containment
devices within the containment module. No work is conducted
in open vessels on the open bench.
The work surfaces of biological safety cabinets and other
containment equipment are decontaminated when work with
infectious materials is finished. Plastic-backed paper
toweling used on nonperforated work surfaces within
biological safety cabinets facilitates clean-up.
An insect and rodent control program is in effect.
Laboratory clothing that protects street clothing (e.g.,
solid-front or wrap- around gowns, scrub suits, coveralls)
is worn in the laboratory. Laboratory clothing is not worn
outside the laboratory, and it is decontaminated before
being laundered.
Special care is taken to avoid skin contamination with
infectious materials; gloves are worn when handling
infected animals and when skin contact with infectious
materials is unavoidable.
Molded surgical masks or respirators are worn in rooms
containing infected animals.
Animals and plants not related to the work being conducted
are not permitted in the laboratory.
All waste from laboratories and animal rooms is
appropriately decontaminated before being disposed of.
Vacuum lines are protected with high-efficiency particulate
air (HEPA) filters and liquid disinfectant traps.
Hypodermic needles and syringes are used only for
parenteral injection and aspiration of fluids from
laboratory animals and diaphragm bottles. Only
needle-locking syringes or disposable syringe-needle units
(i.e., the needle is integral to the syringe) are used for
the injection or aspiration of infectious fluids. Extreme
caution is used when handling needles and syringes to avoid
autoinoculation and the generation of aerosols during use
and disposal. A needle should not be bent, sheared,
replaced in the sheath or guard, or removed from the
syringe following use. The needle and syringe should be
promptly placed in a puncture-resistant container and
decontaminated, preferably by autoclaving, before being
discarded or reused.
Spills and accidents that result in overt or potential
exposures to infectious material are immediately reported
to the laboratory director. Appropriate medical evaluation,
surveillance, and treatment are provided, and written
records are maintained.
Baseline serum samples for all laboratory and other at-risk
personnel are collected and stored. Additional serum
specimens may be collected periodically, depending on the
agents handled or the function of the laboratory.
A biosafety manual is prepared or adopted. Personnel are
advised of special hazards and are required to read
instructions on practices and procedures and to follow
them.
C. Containment equipment
Biological safety cabinets (Class I, II, or III) or other
appropriate combinations of personal-protection or
physical-containment devices (e.g., special protective clothing,
masks, gloves, respirators, centrifuge safety cups, sealed
centrifuge rotors, and containment caging for animals) are used
for all activities with infectious materials that pose a threat
of aerosol exposure. These include: manipulation of cultures and
of clinical or environmental material that may be a source of
infectious aerosols; the aerosol challenge of experimental
animals; harvesting of tissues or fluids from infected animals
and embryonated eggs; and necropsy of infected animals.
D. Laboratory facilities
The laboratory is separated from areas that are open to
unrestricted traffic flow within the building. Passage
through two sets of doors is the basic requirement for
entry into the laboratory from access corridors or other
contiguous areas. Physical separation of the
high-containment laboratory from access corridors or other
laboratories or activities may also be provided by a
double-doored clothes-change room (showers may be
included), airlock, or other access facility that requires
passing through two sets of doors before entering the
laboratory.
The interior surfaces of walls, floors, and ceilings are
water resistant so that they can be easily cleaned.
Penetrations in these surfaces are sealed or capable of
being sealed to facilitate decontaminating the area.
Bench tops are impervious to water and resistant to acids,
alkalis, organic solvents, and moderate heat.
Laboratory furniture is sturdy, and spaces between benches,
cabinets, and equipment are accessible for cleaning.
Each laboratory contains a sink for washing hands. The sink
is foot, elbow, or automatically operated and is located
near the laboratory exit door.
Windows in the laboratory are closed and sealed.
Access doors to the laboratory or containment module are
self-closing.
An autoclave for decontaminating laboratory wastes is
available, preferably within the laboratory.
A ducted exhaust-air ventilation system is provided. This
system creates directional airflow that draws air into the
laboratory through the entry area. The exhaust air is not
recirculated to any other area of the building, is
discharged to the outside, and is dispersed away from
occupied areas and air intakes. Personnel must verify that
the direction of the airflow is proper (i.e., into the
laboratory). The exhaust air from the laboratory room can
be discharged to the outside without being filtered or
otherwise treated.
The HEPA-filtered exhaust air from Class I or CLass II
biological safety cabinets is discharged directly to the
outside or through the building exhaust system. Exhaust air
from Class I or II biological safety cabinets may be
recirculated within the laboratory if the cabinet is tested
and certified at least every 12 months. If the
HEPA-filtered exhaust air from Class I or II biological
safety cabinets is to be discharged to the outside through
the building exhaust system, it is connected to this system
in a manner (e.g., thimble-unit connection) that avoids any
interference with the air balance of the cabinets or
building exhaust system.
Doors to animal rooms open inward, are self-closing, and
are kept closed when infected animals are present.
Work surfaces are decontaminated after use or spills of
viable materials.
Eating, drinking, smoking, and storing of food for human
use are not permitted in animal rooms.
Personnel wash their hands after handling cultures and
animals and before leaving the animal room.
All procedures are carefully performed to minimize the
creation of aerosols.
An insect and rodent control program is in effect.
B. Special practices
Cages are decontaminated, preferably by autoclaving, before
being cleaned and washed.
Surgical-type masks are worn by all personnel entering
animal rooms housing nonhuman primates.
Laboratory coats, gowns, or uniforms are worn while in the
animal room. This protective clothing is removed before
leaving the animal facility.
The laboratory or animal-facility director limits access to
the animal room only to personnel who have been advised of
the potential hazard and who need to enter the room for
program or service purposes when work is in progress. In
general, persons who may be at increased risk of acquiring
infection or for whom infection might be unusually
hazardous are not allowed in the animal room.
The laboratory or animal-facility director establishes
policies and procedures whereby only persons who have been
advised of the potential hazard and who meet any specific
requirements (e.g., vaccination) may enter the animal room.
When an infectious agent in use in the animal room requires
special-entry provisions (e.g., vaccination), a hazard
warning sign (incorporating the universal biohazard symbol)
is posted on the access door to the animal room. The hazard
warning sign identifies the infectious agent, lists the
name and telephone number of the animal-facility supervisor
or other responsible person(s), and indicates the special
requirement(s) for entering the animal room.
Special care is taken to avoid contaminating skin with
infectious material; gloves should be worn when handling
infected animals and when skin contact with infectious
materials is unavoidable.
All waste from the animal room is appropriately
decontaminated--preferably by autoclaving--before being
disposed of. Infected animal carcasses are incinerated
after being transported from the animal room in leakproof,
covered containers.
Hypodermic needles and syringes are used only for the
parenteral injection or aspiration of fluids from
laboratory animals and diaphragm bottles. Only
needle-locking syringes or disposable syringe-needle units
(i.e., the needle is integral to the syringe) are used for
the injection or aspiration of infectious fluids. A needle
should not be bent, sheared, replaced in the sheath or
guard, or removed from the syringe following use. The
needle and syringe should be promptly placed in a
puncture-resistant container and decontaminated, preferably
by autoclaving, before being discarded or reused.
If floor drains are provided, the drain taps are always
filled with water or a suitable disinfectant.
When appropriate, considering the agents handled, baseline
serum samples from animal-care and other at-risk personnel
are collected and stored. Additional serum samples may be
collected periodically, depending on the agents handled or
the function of the facility.
C. Containment equipment
Biological safety cabinets, other physical-containment devices,
and/or personal-protection devices (e.g., respirators, face
shields) are used when procedures with a high potential for
creating aerosols are conducted. These include necropsy of
infected animals, harvesting of infected tissues or fluids from
animals or eggs, intranasal inoculation of animals, and
manipulation of high concentrations or large volumes of
infectious materials.
D. Animal facilities
The animal facility is designed and constructed to
facilitate cleaning and housekeeping.
A sink for washing hands is available in the room that
houses infected animals.
If the animal facility has windows that open, they are
fitted with fly screens.
It is recommended, but not required, that the direction of
airflow in the animal facility is inward and that exhaust
air is discharged to the outside without being recirculated
to other rooms.
An autoclave that can be used for decontaminating
infectious laboratory waste is available in the same
building that contains the animal facility. Animal
Biosafety Level 3
Standard practices
Doors to animal rooms open inward, are self-closing, and
are kept closed when work with infected animals is in
progress.
Work surfaces are decontaminated after use or after spills
of viable materials.
Eating, drinking, smoking, and storing of food for human
use are not permitted in the animal room.
Personnel wash their hands after handling cultures or
animals and before leaving the laboratory.
All procedures are carefully performed to minimize the
creation of aerosols.
An insect and rodent control program is in effect.
B. Special practices
Cages are autoclaved before bedding is removed and before
they are cleaned and washed.
Surgical-type masks or other respiratory protection devices
(e.g., respirators) are worn by personnel entering rooms
that house animals infected with agents assigned to
Biosafety Level 3.
Wrap-around or solid-front gowns or uniforms are worn by
personnel entering the animal room. Front-button laboratory
coats are unsuitable. Protective gowns must remain in the
animal room and must be decontaminated before being
laundered.
The laboratory director or other responsible person limits
access to the animal room only to personnel who have been
advised of the potential hazard and who need to enter the
room for program or service purposes when infected animals
are present. In general, persons who may be at increased
risk of acquiring infection or for whom infection might be
unusually hazardous are not allowed in the animal room.
The laboratory director or other responsible person
establishes policies and procedures whereby only persons
who have been advised of the potential hazard and meet any
specific requirements (e.g., vaccination) may enter the
animal room.
Hazard warning signs (incorporating the universal biohazard
warning symbol) are posted on access doors to animal rooms
containing animals infected with agents assigned to
Biosafety Level 3 are present. The hazard warning sign
should identify the agent(s) in use, list the name and
telephone number of the animal room supervisor or other
responsible person(s), and indicate any special conditions
of entry into the animal room (e.g., the need for
vaccinations or respirators).
Personnel wear gloves when handling infected animals.
Gloves are removed aseptically and autoclaved with other
animal room waste before being disposed of or reused.
All wastes from the animal room are autoclaved before being
disposed of. All animal carcasses are incinerated. Dead
animals are transported from the animal room to the
incinerator in leakproof, covered containers.
Hypodermic needles and syringes are used only for gavage or
parenteral injection or aspiration of fluids from
laboratory animals and diaphragm bottles. Only
needle-locking syringes or disposable syringe-needle units
(i.e., the needle is integral to the syringe) are used. A
needle should not be bent, sheared, replaced in the sheath
or guard, or removed from the syringe following use. The
needle and syringe should be promptly placed in a
puncture-resistant container and decontaminated, preferably
by autoclaving, before being discarded or reused. When
possible, cannulas should be used instead of sharp needles
(e.g., gavage).
If floor drains are provided, the drain traps are always
filled with water or a suitable disinfectant.
If vacuum lines are provided, they are protected with HEPA
filters and liquid disinfectant traps.
Boots, shoe covers, or other protective footwear and
disinfectant footbaths are available and used when
indicated.
C. Containment equipment
Personal-protection clothing and equipment and/or other
physical-containment devices are used for all procedures
and manipulations of infectious materials or infected
animals.
The risk of infectious aerosols from infected animals or
their bedding can be reduced if animals are housed in
partial-containment caging systems, such as open cages
placed in ventilated enclosures (e.g., laminar-flow
cabinets), solid-wall and -bottom cages covered by filter
bonnets, or other equivalent primary containment systems.
D. Animal facilities
The animal facility is designed and constructed to
facilitate cleaning and housekeeping and is separated from
areas that are open to unrestricted personnel traffic
within the building. Passage through two sets of doors is
the basic requirement for entry into the animal room from
access corridors or other contiguous areas. Physical
separation of the animal room from access corridors or from
other activities may also be provided by a double-doored
clothes change room (showers may be included), airlock, or
other access facility that requires passage through two
sets of doors before entering the animal room.
The interior surfaces of walls, floors, and ceilings are
water resistant so that they can be cleaned easily.
Penetrations in these surfaces are sealed or capable of
being sealed to facilitate fumigation or space
decontamination.
A foot, elbow, or automatically operated sink for hand
washing is provided near each animal-room exit door.
Windows in the animal room are closed and sealed.
Animal room doors are self-closing and are kept closed when
infected animals are present.
An autoclave for decontaminating wastes is available,
preferably within the animal room. Materials to be
autoclaved outside the animal room are transported in a
covered, leakproof container.
An exhaust-air ventilation system is provided. This system
creates directional airflow that draws air into the animal
room through the entry area. The building exhaust can be
used for this purpose if the exhaust air is not
recirculated to any other area of the building, is
discharged to the outside, and is dispersed away from
occupied areas and air intakes. Personnel must verify that
the direction of the airflow is proper (i.e., into the
animal room). The exhaust air from the animal room that
does not pass through biological safety cabinets or other
primary containment equipment can be discharged to the
outside without being filtered or otherwise treated.
The HEPA-filtered exhaust air from Class I or Class II
biological safety cabinets or other primary containment
devices is discharged directly to the outside or through
the building's exhaust system. Exhaust air from these
primary containment devices may be recirculated within the
animal room if the cabinet is tested and certified at least
every 12 months. If the HEPA- filtered exhaust air from
Class I or Class II biological safety cabinets is
discharged to the outside through the building exhaust
system, it is connected to this system in a manner (e.g.,
thimble-unit connection) that avoids any interference with
with the air balance of the cabinets or building exhaust
system.
ADDENDUM 2
CDC cautionary notice for all human-serum-derived reagents used
as controls:
WARNING: Because no test method can offer complete assurance that
laboratory specimens do not contain HIV, hepatitis B virus, or
other infectious agents, this specimen should be handled at the
BSL 2 as recommended for any potentially infectious human serum
or blood specimen in the CDC-NIH manual, Biosafety in
Microbiological and Biomedical Laboratories, 1984, pages 11-13.
If additional statements describing the results of any heat
treatment or serologic procedure(s) already performed on the
human-serum reagent or control are used in conjunction with the
above cautionary notice, these statements should be worded so as
not to diminish the impact of the warning that emphasizes the
need for universal precautions.
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