Biomedical Engineering Reference
In-Depth Information
Sharp, contaminated necropsy instruments always pose
a threat of accidental autoinoculation to the worker.
Aerosols may be created when cavities are opened, tissues
are incised, and fluids are sampled.
If an experimental or natural pathogen is known to be
involved, biosafety precautions commensurate with the
biosafety level for that agent should be the minimal criteria.
However, the cause of death of nonhuman primates is often
undetermined at necropsy for which the associated
biohazards are indeed unknown. The minimal protection
for anyone conducting a necropsy on any nonhuman
primate should be head protection, double gloves, face-
mask, face shield/goggles, waterproof shoe covers/boots,
and waterproof, disposable garments.
A dedicated necropsy facility is recommended. These
areas include equipment and features such as a downdraft
necropsy table, a one-pass air system for the room, an
oscillating saw with a vacuum adapter, adequate lighting,
and an array of necropsy instruments and tissue collection
materials. A biosafety cabinet may be used for certain work
involving special pathogens or small nonhuman primates.
Numerous facilities do not have dedicated space for
necropsies, and appropriatemeasuresmust bemade available
when needed. An empty animal room that can be decon-
taminated following necropsy may be a suitable location.
Normally, necropsies are not conducted in areas housing
animals. Most necropsies in this country require a minimum
of BSL-2 recommendations and some require BSL-3.
Because necropsy of nonhuman primates is such
potentially dangerous work, only properly trained and
experienced personnel should be allowed to conduct
nonhuman primate necropsies. Furthermore, proper
instruments and equipment to permit safe performance of
these procedures are critical.
Safe containment and proper labeling of blood, tissues, and
other items to be removed and transported from the necropsy
area to another location are important because accidents en
route may unnecessarily expose others to pathogens.
The proper disposal of carcasses and animal remains after
necropsy is essential. Usually double bagging in leak proof
bags with proper identification is necessary to transport for
incineration, tissue digesters, or other disposal means.
After necropsy procedures are completed, the necropsy
area should be decontaminated. Minimally, the necropsy
table, surfaces near the immediate work area, and the floor
of the immediate area should be decontaminated with
a suitable disinfecting solution such as diluted household
bleach or quaternary ammonium compounds.
In some situations, physical restraint of nonhuman
primates is necessary. With proper precautions, such
restraints may be used for handling certain species of
nonhuman primates, infant and very small nonhuman
primates, and those undergoing training regimens or in
studies precluding the administration of exogenous chem-
icals. In all cases, extreme caution must be used because
one is in direct contact with an alert animal capable of
inflicting a scratch or a serious penetrating or crushing bite
or of transmitting a natural or experimental pathogen.
Additionally, the facility must have an SOP for dealing with
escaped animals and adequately trained staff to prevent
injury to personnel or the escaped animal.
Persons handling nonhuman primates and using phys-
ical restraint must be knowledgeable and experienced.
They should never work alone, especially with a potentially
dangerous or unanesthetized animal in case emergency
assistance is required. Workers must be properly attired
with protective devices and clothing.
Nets and leather gloves are used in many facilities for
physical restraint. They should be free of defects and
repaired or replaced as necessary, as should all equipment
used in the physical restraint of nonhuman primates. Sharp
canine teeth can penetrate leather gloves.
Squeeze-back cages are necessary for working with
most nonhuman primates. A number of technical proce-
dures (inspections, bleedings, samplings, etc.) may be
performed safely through the cage structure itself, partic-
ularly with nonhuman primates that have been trained for
certain presentations.
Pole and collar techniques may be satisfactorily
employed under certain conditions. Restraint chairs may be
used rarely and with due consideration to the duration of
restraint and distress to the animal.
Chemical restraint is highly recommended in most
situations. The most commonly used chemical restraint
agent is ketamine hydrochloride. Its induction time and
effect are variable in certain individual nonhuman primates,
and extra caution should be exercised when hands-on
contact is first made. Also, some nonhuman primates
recover much faster than others and anesthetized animals
should never be left unmonitored. Nonhuman primates that
receive multiple injections of ketamine hydrochloride over
an extended period may become refractory to the drug.
Agents such as teletamine hydrochloride offer a prolonged
period of anesthesia and analgesia and can be used for
performing minor operative procedures. Additional
anesthetic, needle, and syringe should be nearby at all times
while the animal is out of its primary enclosure. Safe
handling of syringes and needles used to administer anes-
thetics is essential to prevent exposure to known or unknown
agents. A biohazard sharps container must be present so that
used needles can be safely disposed of and personnel must be
trained to never re-cap a needle prior to disposal.
Physical and Chemical Restraint
Nonhuman primates must be restrained humanely and
properly to prevent injury and undue distress to the animal
as well as for the safety of the worker.
