VIII. OCCUPATIONAL
HEALTH AND SAFETY
Those working with experimental animals risk exposure
to physical hazards (e.g., heat, noise, radiation), chemical hazards (e.g.,
disinfectants, cleaning solutions), as well as intestinal parasites, enteric
bacteria, pathogenic organisms, and animal bites (Soave and Brand, 1991). As
well, those working with swine in confinement buildings may suffer future chronic
and irreversible lung damage, according to Donham and Leininger (1984). Those
working with non-human primates (NHP) must take special precautions. Guidance
for these individuals may be found in Volume 2 of this Guide.
A. REGULATORY REQUIREMENTS
As is the case with other laboratories,
the animal care facility should have an Occupational Health and Safety
program. All persons using the facility should also be familiar with the
requirements of relevant federal, provincial and municipal legislation.
This would include, for example, the federal Health of Animals Act (38-39
Elizabeth II, Chapter 21, pgs. 387-421), which replaced the Animal Disease
and Protection Act and which governs control of animal diseases and toxic
substances. Those working with animals should also be cognizant of institutional
and/or facility safety program (see also Volume 2 of this Guide
[CCAC, 1984a]).
The Workplace Hazardous Materials Information
System (WHMIS), which resulted from federal and provincial co-operation,
was instituted in 1988. Federal government laboratories are governed by
federal WHMIS and the Canada Labour Code. The following publications are
available free of charge from Labour Canada: The Employer and WHMIS;
Introduction to the WHMIS Program; Exercise WHMIS in the Workplace,
and a relevant poster.
Elsewhere, provincially enacted Health
and Safety legislation specifies the accountability of owners and directors
and the rights and responsibilities of employers, supervisors and workers
in the workplace. The right to refuse unsafe work is a part of the Occupational
Health and Safety (OHS) Act. WHMIS regulations are also a section of this
legislation and require that each employer provide safe working conditions
and that employees be informed about all hazards they will face in the
course of their duties. Employees are also given the right to withdraw
from the workplace if faced with an unsafe condition. All hazardous substances,
including microorganisms, must be labelled in a specified manner, and a
Material Safety Data Sheet (MSDS) must be available to accompany each hazardous
substance. Each province has adapted these federal government guidelines
for its own purposes. WHMIS material may be obtained from provincial Ministries
of Labour.
All personnel working with animals must
understand how to handle the species involved, both for their own safety
and health, and for that of the animals. Training for this should be provided.
B. BIOLOGICAL HAZARDS
Guidelines for working with biohazards
(e.g., bacteria, viruses, parasites, fungi and other infectious agents),
are provided in the Health and Welfare Canada/Medical Research Council
Laboratory
Biosafety Guidelines (HWC/MRC, 1990). The guidelines include such items
as biohazard containment, laboratory design, personal hygiene and safety
facilities, and can be used to provide training for employees as mandated
by WHMIS.
The biosafety guidelines apply to all research
carried out or supported by the federal government and have been adopted
by many industries.
Standard Operating Procedures (SOP) based
on the guidelines, aimed at minimizing risks to humans in biohazard risk
areas, should be developed and enforced.
Personal cleanliness is an important barrier
to infection and washing of hands after handling any animal will reduce
the risk of disease spread and self-infection. All employees working with
animals, as well as visitors to the facility, should wear protective clothing,
minimally a lab coat.
All contaminated material must be decontaminated
before disposal. Necropsy of animals infected with highly infectious agents
should be carried out in certified and tested biological safety cabinets.
Necropsy material for disposal should be sealed in plastic bags, properly
labelled and incinerated. The necropsy room should be properly equipped
to provide adequate refrigeration and hand-washing facilities.
C. ZOONOSES
Those infections that are "secondarily
transmitted from animals to humans" are referred to as zoonoses (Schnurrenberger
and Hubbert, 1981; August and Loar, 1987; Acha and Szyfres, 1989) and can
seriously affect research (Hamm, 1986; Bhatt, Jacoby, Morse et al.
1986; ILAR/NRC, 1991).
While most infectious agents show a considerable
degree of species specificity, they also may, from time to time, vary widely
in virulence and in their capacity to break through species barriers. Thus,
infections that have not commonly been considered to be zoonotic hazards
may sporadically affect susceptible persons or animals. Persons potentially
at higher risk are those who suffer from defective immune systems and those
who are under severe stress or who have non-overt clinical disease. Numerous
pathogenic microorganisms, such as those responsible for tuberculosis,
brucellosis, rabies, etc., which are normally perpetuated by direct transmission
from one or more species of vertebrate animals, are also readily transmissible
to humans.
Transmission of infections from animals
to humans can generally be avoided through proper veterinary care and adherence
to SOPs for control of transmission. However, when animals are obtained
from areas in which zoonotic diseases are known to exist, e.g., in NHP
acquired from the wild (Houghton, 1986) special attention is required.
Work involving exposure to hazardous microorganisms
might require prior immunization of the staff, if a vaccine is available.
It is recommended, for example, that all personnel handling random-source
dogs and cats, including dealers and handlers, should receive routine rabies
vaccination (see also Special Animal Colonies, Infectious Disease Units).
Serological testing and banking of reference
serum samples from all personnel working in the animal facility is advisable.
This is of particular importance where NHP are being handled and/or agents
infectious to humans are being used.
Caution should be exercised in assigning
women
of childbearing status to animal care duties that might expose them to
potential or known teratogens. For example
Toxoplasma gondii, a
protozoan that infects most species of warm-blooded animals, including
humans, is spread primarily by oocysts shed in cat feces. These oocysts
sporulate in two to four days and may survive for more than a year (Fraser
and Mays, 1986). Human toxoplasmosis can result in spontaneous abortion,
prematurity, stillbirth or congenital defects (Schnurrenberger and Hubbert,
1981).
The life cycle of the causative organisms
implicated in a number of indirect zoonoses may involve transmission through
one or more other vertebrate and/or invertebrate intermediate hosts before
affecting humans (for example, in taeniasis, tularemia, and vesicular stomatitis).
Amongst invertebrate vectors of zoonotic disease, the biting insects are
the main offenders. A list of some of the diseases transmitted to humans
from animals is included in Appendix VII.
The role of cold-blooded vertebrates in
the epidemiology of zoonoses should not be overlooked. In particular, turtles
infected with salmonella may constitute a human health hazard in the student
laboratory as well as in the animal facility (Sherris, 1990).
D. PROCEDURES FOR WORKING
WITH NON-HUMAN PRIMATES
This topic has also been discussed in Volume
2 of this Guide (CCAC, 1984b).
All animals must be regarded as potential
sources of zoonoses, although the risk of this occurring will vary widely
with the class, species, and source of the animal involved. In general,
the more closely related phylogenetically a species is to humans, (Anon.,
1987a, 1987b; FRAME, 1987; Rice, 1987a, 1987b), the greater the likelihood
of zoonoses. It is for this reason that special precautions must be followed
for NHP (Love, 1980; Wong and Gardell, 1982; Richter, Lehner and Henrickson,
1984; Else, 1988).
Each institution that maintains a NHP facility
is responsible for providing the proper veterinary and human medical services
to safeguard the health and safety of both personnel and animals. International
guidelines have been prepared for those working with NHP (FRAME/CREA, 1987;
Kaplan, 1987; Anon., 1989; MRC, 1985).
Outbreaks of viral diseases, e.g., Callitrichid
Hepatitis Virus (Anderson, 1991) recently "rocked the primatologist's world,"
and current procedures for the rapid diagnosis of primate viral diseases
include serology, virus isolation, direct visualization using electronmicroscopy
or immunofluorescence, and detection of viral components (Kalter and Herberling,
1990).
The most reasonable and effective approach
in reducing occupational infection risks is to develop and follow SOPs
that preclude or minimize overt occupational exposure among personnel working
with NHP or biological samples therefrom. SOPs should be established for
an Occupational Health and Safety Program for personnel which would include
serological screening and vaccination, use of protective clothing, containment,
stress on personal hygiene, procedures for accidents including bite wounds
and/or other exposure to potential risk, and for quarantine and quality
control procedures for confined animals.
Guidelines have been prepared for prevention
of Herpes Simiae (B-Virus) infection by a B-Virus Working Group
which convened at the Centers for Disease Control (Anon., 1987c; Kaplan,
Balk, Brock et al. 1987; Schulhof, 1990). Herpes Simiae is
fatal in humans (Kalter and Herberling, 1989).
Similarly, because of the expanding use
of Simian Immunodeficiency Virus (SIV), which is closely related to the
Human Immunodeficiency Virus (HIV), guidelines in this regard have been
prepared as well (Anon., 1989). Standard serological procedures to identify
SIV antibody are used in laboratories conducting research with the virus,
and the National Institutes of Health (NIH) and World Health Organization
(WHO) have expanded their diagnostic services (Kalter, 1987).
In addition to NHP from the wild, those
within the colony may also carry indigenous latent infections (Baulu, Everard
and Everard, 1987; Dance, King, Aucken et al. 1992). It is important
to establish rigid quarantine and quality control procedures for the animal
colony and to better define and be more aware of the potential risks. The
Ebola-like virus outbreak in the U.S. in 1989 exemplified such risks (Anon.,
1990; Anderson, 1990a, 1990b; Dalgard, Hardy, Pearson et al. 1992).
Adherence to the following list of precautions
is recommended:
a) all NHP must be considered as
potentially carrying a disease transmissible to humans;
b) NHP, or anything that has been
in direct contact with them, should not come in contact with the skin;
c) protective clothing, including
coveralls, boot covers, surgical caps, masks and gloves should be worn
when working with NHP, and removed when leaving the NHP quarters;
d) smoking and bringing food and
drink into NHP rooms are strictly forbidden;
e) facilities for washing hands
must be made available and used by all personnel immediately upon leaving
NHP rooms;
f) personnel with sores, cuts, and
other lacerations should not come in contact with NHP. However, if this
is unavoidable, then the lesion must be adequately covered prior to and
during any activity in a room containing NHP, and dressings must be changed
immediately upon leaving. These dressings and any other disposable items
so exposed must be treated as biological hazardous waste;
g) all cuts, bites, scratches, or
needle punctures acquired while working with or in proximity of NHP must
be reported to the medical authority designated by the institution. SOPs
for all wounds so encountered should be developed and followed accordingly.
Immediate treatment must ensure that the wound is made to bleed freely
and thoroughly scrubbed and cleansed with soap and water. A flushing of
the wound area with a provodine iodine solution is recommended. In the
event that sterility has been breached (e.g., tearing or puncture of a
surgical glove) the hands must be re-scrubbed before leaving the room and
re-gloved before continuing the procedure.
Following injury by a NHP, the animal concerned
must immediately be immobilized and examined for excessive salivation and
for lesions of the oral cavity which may be characteristic of Herpes (B-Virus).
SOPs must be followed for dealing with this type of accident. Procedures
for sampling for Herpes B of the animal and of the injured person must
be followed. The results of the examination must be communicated to the
previously designated medical authorities, along with information on the
species of NHP, length of time in the colony, and contacts with other species;
h) special precautions should be
taken whenever conducting necropsies on NHP that have died during the conditioning
period; necropsy procedures should include the wearing of protective clothing,
surgical caps, and masks, gowns and surgical gloves. The use of biosafety
cabinets for conducting all necropsy of NHP tissue is
recommended;
i) because of the possible danger
of contacting Hepatitis A, it is recommended that personnel working with
newly imported chimpanzees receive hyper-immune serum globulin prophylactically.
Animals should be tested for human hepatitis antigens and, if positive,
strictly quarantined;
j) all personnel having contact
with NHP must be free of tuberculosis and should receive a tuberculin
skin test not less than once yearly and X-ray examination as prescribed.
It should be noted that it has recently been reported that misleading positive
tuberculin reactions were caused in squirrel monkeys that had received
Freund's Complete Adjuvant (FCA) (Pierce and Dukelow, 1988);
k) protective leather gauntlets
should be worn when handling conscious NHP. Several varieties are available
commercially;
l) all laundry that has been in
direct contact with NHP or their excreta should be autoclaved prior to
being sent out for washing.
E. ALLERGIES
Allergies to laboratory animals are a significant
occupational health concern for people regularly working with the common
laboratory animal species (Aoyama, Ueda, Manda et al. 1992; Olson,
1986; Bland, Levine, Wilson et al. 1986; Botham, Davies and Teasdale,
1987; Kibby, Powell and Cromer, 1989; Lutsky, 1987; Slovak and Hill, 1987;
Venables, Tee, Hawkings
et al. 1988). Laboratory animal allergy
(LAA) is an immediate-type hypersensitivity reaction, IgE-mediated, which
develops upon exposure to a laboratory animal, its fur or dander, its urine,
saliva, serum or other body tissues. Typical symptoms range from mild (e.g.,
upper respiratory signs such as sneezing, itchy and/or runny nose and eyes,
and skin reactions such as red, raised and itchy wheals after contact with
animals, their tissues or their excreta), to severe [e.g., wheezing, shortness
of breath, and a feeling of chest tightness (asthma)]. Persons experiencing
such symptoms should be advised to contact their physician for diagnosis
and treatment.
Measures which can reduce the degree of
exposure to laboratory animal allergens include:
a) use of protective gear such as
gloves, face masks, gowns, shoe covers, etc., worn only in animal rooms;
b) regular hand-washing, and showering
after work;
c) use of improved filtration in
animal room ventilation systems, and the use of special filtered caging
systems; and
d) educational programs for employees
identifying high risk (e.g., high allergen load) areas and tasks, and strict
use of preventive measures, as set out by the institution's SOPs.
Institutions are encouraged to include
a consideration of LAA in their Occupational Health and Safety programs.
As noted above, identifying high risk areas and tasks (Eggleston, Newill,
Ansari et al. 1989; Gordon, Tee, Lowson et al. 1992; Swanson,
Campbell, O'Hallaren et al. 1990), and the use of SOPs in these
areas, along with education of staff, are useful in reducing the severity
of the problem (Botham, Davies and Teasdale, 1987). Procedures for monitoring
exposure, health-monitoring of staff at risk, and for dealing with staff
who become allergic should also be considered (Botham, Davies and Teasdale,
1987; Lutsky, 1987; Newill, Evans and Khoury, 1986).
F. PHYSICAL INJURIES
AND CHEMICAL HAZARDS
Physical injuries related to the handling
of animals may be kept to a minimum by ensuring that:
a) all staff are trained and experienced
in handling the species with which they work, and that they know the particular
hazards associated with each species;
b) all staff are familiar with the
hazards of the experiment, and are provided with (and use) a proper working
area, protective clothing and equipment;
c) a mechanism is in place in every
unit to deal with animal-inflicted injury, and for referral for any further
medical treatment if this is required.
Responsibility for ensuring that first
aid kit(s) are available and always properly stocked must be clearly identified.
The location of the first aid kit(s) should be prominently marked and all
personnel using the facility should be made aware of these locations.
Injuries from chemicals can be avoided
by treating all chemicals with care, by knowing their properties and adhering
to the accepted safety practices for handling that type of product. WHMIS,
legislative and institutional requirements must be met.
Care should always be taken in handling
such common chemicals as industrial detergents used in cage washers, cleaning
agents, and powerful disinfectants. These substances should be stored separate
from animal feed and bedding materials. Volatile liquids used as anesthetics
or for euthanasia, and other toxic and volatile materials, should be stored
in well-ventilated fume hoods or cabinets designed for that purpose.
G. RADIATION AND ULTRAVIOLET
LIGHT
Radioactive materials present special hazards.
All persons working with these materials should know the properties of
each, and be familiar with the appropriate safe handling techniques. The
possession of radioactive materials is authorized by Radioisotope Licences
issued by the (federal) Atomic Energy Control Board (AECB) to the institutions.
The Radiation Safety Program is administered by a Radiation Safety Officer,
who the AECB recommends sit as an ex-officio member of the institution's
Occupational Health and Safety Committee. Use of X-rays is governed by
Occupational Health and Safety Acts under provincial Ministries of Labour.
Isotope-treated animals may pass radioactive
material in their excrement, which should therefore be disposed of in an
approved manner, as must the animal itself after death. Complete records
should be kept through to the final disposition of these animals.
The eye and skin are critical areas for
exposure to ultraviolet (UV) light. The eye, in particular, can be seriously
injured. Staff should not be exposed to UV rays; however, if they must
be, they should be warned of the hazards and provided with "wraparound"
safety glasses. As well, the source of illumination should be suitably
marked. The maximum intensities tolerated by sensitive faces for a seven-hour
day, range from 0.1 to 0.5 milliwatt per square foot.
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