Occupational Issues in Laboratory Animal Handling
Raj Puri, MD, MPHClinical Assistant Professor of Medicine, Section of Occupational MedicineDirector of Strategic Health Initiatives & InnovationStanford University
Disclosure
I have no financial interests and nothing to disclose
Outline
I. Introduction
II. Oversight and Ethics
III. Animal handling: definition and techniques
IV. Unique Occupational hazards in lab animals
V. Cases
VI. Summary
Introduction
Occupational safety and health considerations are primary concerns of animal care and use program management regardless of the size of the program or facility
Hazard identification must be undertaken
Job hazard analysis (JHA) or job safety analysis (JSA) – subsequent risk assessment
Mitigation of identified hazards should follow the broadly accepted approach using the “hierarchy of controls” strategy
Roles and Responsibilities of Overseers
Strong, institutional commitment to safe and compassionate conduct of research
Team-based approach– At a minimum, occupational safety and health management team is
composed of a veterinarian with experience and training in the species
– Facility manager
– Safety and health specialist
Animal care and use committee or oversight body– ensuring an effective occupational safety and health program
– AAALAC accreditation (nonprofit and voluntary), every 3 years
Ethical and legal responsibility
• Careful handling so not to suffer from unnecessary pain
• Providing good care towards the health and well-being of animals
• Animal awareness of the handler’s presence before attempting to restrain them, particularly if the animal is initially asleep • Reduces stress for the animal and decreases risk to bite injuries
History Types of Animals Used in Labs
What is Animal Handling?
Definition: – Term describing how humans work with, respond to, and interact with
animals within their surroundings
– Includes all species, and all parts of production
Types of workers doing the handling– Researchers eg performing injections, surgeries, etc
– Staff eg animal technicians, census techs, etc
Specifics of Animal Handling1? Holding and restraining
Oral feeding
Subcutaneous and Intraperitoneal injections
Blood collections eg tail veins, etc
Husbandry practices eg including sanitation, diet, and adequate space
Health monitoring and record keeping
Species interactions, in the same room or area
Cages with bedding, cage changing and dumping soiled bedding in cage wash area
Surgeries and anesthesia administration
• 1AAALAC international 2020
PPE examplesHazards PPE
Source: NIH‐ Animal Research Advisory Committee, Guidelines for personnel protection in animal facilities, 2016
Types of lab animals
Large– Monkeys, pigs, dogs and cats
Small– Rodents (mice and rats), rabbits and frogs
Lab animal use
• “In Vivo” experiments when the whole intact animal is used
• “Ex Vivo” experiments when only a part of the animal is used– organ (e. g. heart, uterus, trachea. etc. )
– tissue (e. g. skeletal muscle) or cells (e. g. blood cells)
Mice
Most common mammal among laboratory animals
Characteristics– Mice are small weighing about 18 -30 g.
– Very sensitive and consume small doses of drugs
– Can be easily handled
– Highly exploring and mobile
– Drugs are best injected intraperitoneal or intravenously into one of their superficial tail veins
Mouse handling
1) Typically restraining by the tail– Mice may be picked up by grasping the base of the tail
– Do not grasp the tip of the tail, as this may cause the skin to be stripped off
– Only used for brief restraint e.g. transferring animals from cage to cage
– Never suspend the mouse for prolonged periods of time by its tail
2) Forceps Restraint – Picked up with rubber tipped forceps
gently grasping the animal by the scruff of the neck or the base of the tail
short-term procedures such as transferring animals to a new cage
Never suspend the animal for a prolonged period of time with the forceps.
Mouse handling
3) Two-Handed Method Technical procedures: injection and blood collection
– Place the mouse on a rough surface while holding the tail firmly
Note: Smooth surface will frighten the mouse because it cannot get a foothold. This may cause it to turn around and bite in its attempt to escape. Grasp the nape gently and firmly with your free hand and lift the mouse
– Scruff can be grasped between the thumb and forefinger whilst maintaining a grip on the tail
Mouse handling
4) One-handed method– Purpose: injections, ear tagging
– Place the mouse’s tail between the last two fingers of the hand that is holding the nape
Unique Hazards in Care and Use of Lab Animals
A. Allergen exposure
B. Physical hazards
C. Environmental Hazards
D. Zoonotic diseases
E. Hazardous material exposure
Allergens
May develop allergic reactions to an animal protein– found in dander, hair, urine, and saliva
– animal allergens carried through air and surfaces
– tend to stick to fur, dander, bedding, and dust
– those who develop allergy do so within the first 12 months of contact with an animal at home or in the workplace
– earliest symptoms consist of upper airway and skin complaints e.g. nasal congestion or stuffiness, runny nose with nasal drainage, sneezing, red and irritated eyes, skin itching, and hives
mean time to onset of nasal symptoms is seven months from the first exposure
– advanced cases consist of lower airway findings, e.g. cough, wheeze, SOB, asthma, and in rare circumstances, anaphylaxis
Allergen Risk
workers at greatest risk to laboratory animal proteins are those with a hx of allergic reactions to household pets
those at increased risk include those with hx of asthma, seasonal sinus issues, eczema, and other allergies
risks can be minimized by engineering controls, e.g. air containment devices (e.g., biological safety cabinets and chemical fume hoods) and waste handling equipment (e.g., HEPA-filtered bedding dump stations)
respiratory exposures can be controlled by housing animals in filter-topped cages and working in a well-ventilated area, such as a room with nonrecirculating room air or near a fume hood
Allergen Risk
standard operating procedures promoting frequent washing of hands with soap and water– alcohol-based hand rubs can be used but they are not effective for allergens
and not a substitution for hand washing with soap
disposable respirator, such as an N-95, or other negative-pressure respirator, such as a PAPR
Laboratory Animal Allergy (LAA)
Laboratory animal allergy (LAA) is the manifestation of an IgE-associated sensitization to animal proteins– a common cause of occupational allergy and asthma
– a condition that historically afflicted up to 20% of a highly trained workforce
conventional open cages
– evidence of an exposure–response relationship between airborne rat urinary proteins and LAA has long been established
increasing risks of IgE sensitisation and LAA at higher levels of exposure
evidence for allergy to mouse proteins is less clear
Laboratory Animal Allergy (LAA)
Risks of LAA are highest in the early years of employment and an estimated 95% of individuals who develop LAA do so in the first 3 years of exposure
Most studies found no association between smoking and sensitization to, primarily, rats but also other laboratory animal allergens
Atopy was strongly associated with sensitization to mice (Palmberg, 2015; Krop et al, 2011)
Survey study of 750 workers by Feary et al. (2019) demonstrated:– LAA can be “largely prevented” in modern research units using individually
ventilated cages (IVCs) to contain aeroallergen exposure and use of respiratory protection
Asymptomatic sensitization is well recognized may reflect a permanent state or transition phase from immunological
Individually Ventilated Cages (IVC)
LAA diagnosis and treatment Medical evaluation
Hx and PE: nature, severity and pattern of symptoms, temporality
spiro/PFT’s
performed before the beginning of the workweek and towards the end of the shift
decline of at least 20% of the FEV 1 or 25% of the FEF 25-75 is considered significant
symptomatic employee may be given a peak flow meter
serologic testing in occ clinic eg urine, epithelium, and salivary (mouse/rat/rabbit)
daily lower respiratory symptoms may require short- and long-acting beta-receptor agonist bronchodilator therapy and possibly inhaled corticosteroids
Referral to allergist, if needed
Eliminating exposure to allergens is the treatment of choice, if possible
Fitted for N-95 mask
OTC antihistamines eg Zyrtec, Allegra, Claritin prior to exposure
LAA Job options
reducing the airborne allergen through engineering controls
modifying work practices– job or task rotation initiatives
– review personal respiratory protection equipment to enhance comfort and practicality for worker
Physical Hazards
MSK injuries (ergo): Strains, sprains, back injuriesa. Caused by awkward postures (collecting blood/tissue samples, or
administering multiple vaccinations)
highly repetitive motions, hand force (when restraining animals), heavy, frequent, or awkward lifting
b. Slips, trips and falls: might occur when walking on uneven or wet surfaces (spills), PPE can limit your range of motion predisposing to fall
Physical Hazards
Animal-related incidents– Injuries, zoonoses
Bites (mice, police dogs- case of PSO bit by a Palo Alto Police Officer K-9), scratches, crush injuries, kicks
– Insects and wild animals
Vector-borne diseases: some insects transmit vector-borne disease eg Lyme disease or West Nile virus
Prevention: repellents with DEET and Picaridin; long sleeves and long pants
Physical Hazards
Sharps– Needlesticks and scalpel blade cuts common (multiple cases seen with small
and large animal surgeries eg mice, monkeys, pigs, etc)
Prevention:
1) do not recap needles
2) instead, directly dispose of needles into rigid containers
3) account for all sharps before and after use
Physical Hazards
Psychological into physical: Nausea, dizziness, headaches
Cognitive– Disorientation, memory
Emotional – Anxiety, guilt, grief, irritability
– Grief from administering euthanasia
– Stress from working in fast-paced environment and also high-stressenvironment
Behavioral– Anger, withdrawal, depression, drug or alcohol abuse
Environmental Hazards
Temperature/weather– Heat and cold:
Heat: Heat cramps, Heat exhaustion, Heat stroke (life-threatening)
sunburn, dehydration
Prevention: self-monitoring
Take breaks and seek shade
Cooling fans/air conditioning
Keep hydrated, avoid caffeine/alcohol
Cold: if combined with wet and windy conditions can lead to frostbite or hypothermia (symptoms include shivering, lack of coordination, slurred speech, numbness in extremities)
Environmental Hazards
Noise– Power tools, heavy equipment, animal vocalization
– Hazardous at 85dB over 8hour average
Prevention: Hearing Conservation Program (yearly- cage washers)
Roughly gauge loud noise: hazardous levels are probable when holding a conversation or hearing another responder is difficult at 3 feet or arm’s length
Electrical Shock
– Power equipment, power cords, downed power lines
Environmental Hazards Chemical exposure
– Animal waste gases eg ammonia- entering enclosed animal facilities
– Carbon monoxide released from gas-powered tools can build to hazardous levels when used in confined spaces
– Disinfectant products when aerosolized (preparation or application)
Mucous membrane and respiratory tract irritation
– Pesticides
– Waste anesthetic gases
Anesthesia machines vaporize small amounts of liquid drug (isoflurane, sevoflurane, etc) - tubes deliver it to the pt’s airway
When animals exhales, most (up to 90%) of the drug is captured by scavenging systems and the rest usually goes outside
can reach the operator in a number of ways: spills, air leaks, exhale
Environmental Hazards
Radiological hazards – Animals more challenging to image: may need physical restraints and
chemical restraints
– American College of Veterinary Radiology has a position statement on radiation safety
Follows ALARA (As Low As Reasonably Achievable)
Person’s body is never to be in the primary beam, collimation concept
Radiation badges are required
Zoonotic diseases
humans usually not susceptible to infectious diseases suffered by animals, there are some important exceptions
bacterium in the normal flora of a healthy animal may cause a serious disorder in a person exposed to it – because the animal has developed "resistance" to these microorganisms,
whereas humans with no previous exposure to the agent lack this protective immunity
Zoonotic diseases
Q-fever: infected sheep, cattle, goats, rodents, marsupials, fowls and their ticks– by the ricksettial agent Coxiella burnetii
Toxoplasma infectious agent found primarily in cat feces
Orf disease: Contagious ecthyma ("orf") from the mouth of an infected sheep can be transmitted to humans causing focal skin lesions on the hands.
Live Polio- injecting into animals; checking titers
Performing necropsies- rabies, injuries, Qfever, Herpes B
Zoonotic Diseases of Ungulates
Zoonosis in Rodents and rabbits
Relevant Zoonotic Diseases in Laboratory Nonhuman Primates (NHP)
Diarrhea; gram‐negative sepsis Enterobacteriaceae: Salmonella spp., Shigella spp., Campbylobacter spp., Yersenia spp.
Fecal‐oral
Protozoal diarrhea Entamoeba histolytica, Giardia spp., Balantidiumcoli, Cryptosporidium spp.
Fecal‐oral
Tuberculosis Mycobacteria tuberculosis,Mycobacteria bovis Splash, spray, inhalation of aerosols
B‐virus meningoencephalitis Macacine herpesvirus 1 Bite, scratch, splash exposure or blood/tissue exposure to contaminated instruments, needles, and equipment (e.g., cages)
Hepatitis Hepatitis A virus, hepatitis E virus Fecal‐oral
Rabies Rabies virus (Lyssavirus) Wound or bite, contact with saliva or brain
Measles Rubeola virus Splash/spray, aerosols, contact with contaminated fomites
Foamy virus Spumavirus Direct blood/tissue contact with infected tissue or contaminated materials
Herpes simplex Herpes simplex Direct contact
Helminths Oesophagostonum spp., Strongyloides spp. Fecal‐oral
Dermatomycosis (ringworm) Trichophyton spp. Direct contact
Zoonosis Agent Route of transmission
Source: National Institutes of Health”“Animal Research Advisory Committee, Guidelines for personnel protection in animal facilities, 2016
Zoonotic Diseases of Laboratory Fish and Frogs
Case 1 21-year-old female worker at a pharmaceutical company prepared rats for
experiments – no prior respiratory illnesses, but positive family history of allergies
– 3 months after started working, noted hives on forearms and hands
– symptoms worsened until every direct contact with rats produced hives
– wearing gloves alleviated the problem, but could not perform work adequately when using them
Later began to suffer episodes of sneezing, nasal drainage, watery eyes, and chest tightness– transferred to another department, where her symptoms ceased.
– recurred when entered room with rats or where rats had previously been housed
– positive skin tests to animal dander and to rat hair
– had elevated antibodies (IgE) to various rat proteins
Case 2 physician had been working on a research project involving rabbits for
several years – had allergy to cats but not to dust mites or other common allergens
– developed progressively worsening nasal congestion and eye irritation
during work with a rabbit, had a needlestick injury– ~ 15 minutes, developed progressive itching, swelling of the face, hives,
throat tightness, and inability to speak
– admitted to hospital and received emergency treatment for anaphylactic shock
– symptoms stabilized over a 5-hour period
– blood showed increased antibodies (lgE) to cat dander and rabbit epithelium
– antibodies to rabbit epithelium declined over the 6-month period after he left the job that involved rabbit contact
Case 3
38 students examined during their first year of training as laboratory technicians (median age, 21 years) – re-examined after working with various laboratory animals (primarily rats,
mice, and rabbits) for an average of 18 months
– At that time, 9 students (24%) had developed allergies to lab animals
– Symptoms included nasal and eye irritation in 7 students, skin rashes in 4, and chest problems in 3
Of the 9 students with animal allergies, 7 had reaction to rat or mouse antigen in skin-prick tests, and 8 showed asthma like reactions during lung testing
Summary
Dynamic and quality occupational safety and health program is a team event that requires the active, ongoing participation of all personnel
Effective program includes the assessment of facility design and equipment
Establishment of appropriate standard operating procedures and PPE
References
Feary, J., Schofield, S., Canizales, J., Fitzgerald, B., Potts, J.F., Jones, M.G., & Cullinan, P. (2019). Laboratory animal allergy is preventable in modern research facilities. The European respiratory journal, 53 6.
Krop EJ, Doekes G, Heederik DJ, et al. IgG4 antibodies against rodents in laboratory animal workers do not protect against allergic sensitization. Allergy 2011; 66: 517–522.
Palmberg L, Sundblad BM, Lindberg A, et al. Long term effect and allergic sensitization in newly employed workers in laboratory animal facilities. Respir Med 2015; 109: 1164–1173.
MCQ Questions
Question #1
Risks of Laboratory animal allergy (LAA) are highest when in a worker?
– A. first 6 months of working with lab animals
– B. first 1 year
– C. last half of career
– D. first 1 month
– E. first 3 years
MCQ Questions
Question #2
Orf zoonotic disease can be contracted from the mouth of an infected?
A. Pig
B. Cow
C. Rabbit
D. Sheep
E. Mouse
MCQ Questions
Question #3
Which technique in mouse handling is not an accepted method?
A. Forceps technique
B. Tail restraint
C. One hand method
D. Two hand method
E. Head/Jaw restraint (choke hold)