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)