Occupational Issues in Laboratory Animal Handling Raj Puri, MD, MPH - - PDF document

Occupational Issues in Laboratory Animal Handling

Raj Puri, MD, MPH Clinical Assistant Professor of Medicine, Section of Occupational Medicine Director of Strategic Health Initiatives & Innovation Stanford 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 examples

Hazards 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 injuries
• a. 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-stress environment

• 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., Campb ylobacter spp., Yersenia spp. Fecal‐oral Protozoal diarrhea Entamoeba histolytica, Giardia spp., Balantidium coli, 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)