Hazards Associated with Laboratory Animals

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Hazards Associated with Laboratory Animals

• EMD 545b
• Lecture 11

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Physical Hazards

• Ergonomic issues
• Strained postures
• Heavy lifts
• Repetitive motion
• Slips/Trips/Falls
• Noise/Heat in Cage Washing Rooms
• Bites

3
Risks of Work with Research Animals
4
Risks of Work with Research Animals
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Risks of Work with Research Animals
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Zoonoses

• Infectious diseases capable of being transmitted
  from animals to humans

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Dogs and Cats Rabies Virus

• Feral animals represent the greatest risk
• Acquire animals documented free of disease
• Pre-exposure immunization required for exposed
  personnel (3 shot series)
• Titers after vaccination and at 2 year intervals
• Post bite evaluation for need for Rabies booster,
  wound prophylaxis, tetanus

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Dog or Cat - Bites

• Infections common
• Organisms are Staph, Strep, Pasturella, anaerobes
• C. canimorsus
• Proper wound care/ tetanus immunization
• Appropriate antibiotic prophylaxis

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Cats

• Cat scratch disease--Bartonella henselae
• Toxoplasmosis---T.gondii
• Especially important in immunocompromised/pregnant
  workers
• Prevention--good hygiene
• May offer temporary transfer to pregnant women
  without immunity to Toxoplasma
• Yersinia pestis--fleas from cats/ rodents in
  southwest

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Dog and Cat

• Dermatomycosis--ringworm
• Gastrointestinal infections---Salmonella,
  Campylobacter, Shigella,
• Prevent by prompt recognition and isolation of
  ill animals

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Rodents

• Rat Bite Fever-Spirillum minor, Streptobaccilis
  moniliformis
• Leptospirosis
• Lymphocytic choriomeningitis

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Sheep

• Sheep--Q fever (Coxiella burnetti)
• Aerosols from urine, feces, birth products
• Persists in environment
• Nonspecific viral symptoms but serious illness in
  those with pre-existing liver or valvular heart
  disease

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Hepatitis Viruses

• Hepatitis A
• Enteric (oral/fecal spread).
• No chronic carrier state
• Reservoir is man, but occasionally NHPs.
• Vaccine available- not routinely recommended for
  NHP workers.

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Hepatitis Viruses

• Hepatitis B
• Bloodborne
• Low mortality (1 case fatality rate)
• Up to 10 of those infected become chronic
  carriers with high incidence of cirrhosis and
  liver cancer.
• Reservoir is man, chimps are susceptible.
• Vaccine available, but only indicated for
  potential human BBP exposure.

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Hepatitis Virus

• Hepatitis C
• Bloodborne.
• Disease is milder vs. hepatitis B, but higher
  rate of chronic carriers.
• Reservoir is man, chimps are susceptible.
• No vaccine, but treatment within weeks of
  infection can prevent chronic disease.

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Tetanus

• Caused by exotoxin of Clostridium tetani
• Uncommon 1995-1996, 124 U.S. cases reported.
• Case fatality rate proportional to age (2.3 in
  ages 20-39, 18 for gt60) and availability of
  adequate medical care.
• Reservoir is intestines of most animals,
  including humans and NHPs

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Tuberculosis

• Reservoir is man and rarely NHPs, badgers, and
  other mammals.
• NHPs are susceptible.
• Screening is done by intradermal challenge with
  purified protein from M. bovis. Positive tests
  indicate previous infection. Chest x-rays are
  then required to r/o active disease.

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Enteric Infections

• Viral
• Hepatitis A and E
• Possibly rotaviral gastroenteritis
• Bacterial
• Campylobacter jejuni and coli (NHPs may be a
  reservoir).
• Salmonella (NHPs may be a reservoir)
• Shigella (man is reservoir, but outbreaks have
  been reported in NHP colonies).

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Bacterial Infections from Bite Wounds

• gt200 species of bacteria in the mouths of many
  animals, including humans.
• Streptococcal species, staphylococcal species,
  tetanus.
• Bite wounds need to be thoroughly cleaned and
  debrided.
• Prophylaxis for moderate to deep bites with
  Amoxacillin/clavulinic acid (Augmentin).

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Non- Human Primates (NHP)

• Unique hazards
• size
• intelligence
• strength
• Zoonotic hazards
• herpes B virus (Macaques)
• Salmonella
• TB
• SIV, STLV
• endogenous retroviruses

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Simian Immunodeficiency Virus (SIV)

• NHPs may be infected with several retroviruses,
  including simian immunodeficiency virus, simian
  spumaviruses (foamy viruses or SFV), simian
  T-lymphotrophic viruses (STLV), and/or simian
  type D retroviruses (SRV).

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Non Human Primates

• B virus--Cercopithecine herpesvirus 1
• Hepatitis A
• Hepatitis B
• Other exotic agents--Marburg, Ebola, Simian
  immunodefeciency virus

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Non Human Primates

• Screen workers for risk factors
• Enroll in serum banking is recommended
• Prompt recognition and treatment of injuries

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B Virus (Cercopithecine Herpesvirus 1)

• Naturally occurring infection seen only in genus
  Macaca (rhesus, cynomolgus, pig-tailed, others).
• Very high prevalence of captive macaques gt2.5
  years old have been infected. 20 for animals lt
  2.5 years old.
• Infected monkeys may have mild or no symptoms

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B Virus (Cercopithecine Herpesvirus 1)

• Human disease is rare and has been identified in
  about 50 cases and well-documented in 26 cases.
• 70 case fatality rate in humans
• Potentially infectious material
• ocular, oral, genital secretions
• Central nervous system tissue and CSF
• Primary cell cultures from macaque kidneys

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Transmission of CHV-1

• Route of Exposure
• bites and scratches
• needlestick injuries with contaminated needles
  or scalpels, often during surgery
• eye and mucous membrane exposure to body fluids
  or particulates from animal
• most recent death (12/10/97) attributed to an
  unknown particle which entered the eye of a
  researcher at Yerkes Primate Center during
  observation without PPE

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Exposures to Non-Human Primates

• Immediate Response
• Mucous membrane flush in an eye wash or potable
  water for a minimum of 15 minutes.
• Skin exposures Wash with soap and water or
  antiseptic for 15 minutes Consider dilute
  solutions of bleach (Dakins solution) for skin
  and wounds.

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Safe Handling of Non-Human Primates

• Full-length leather gloves and appropriate PPE
• Squeeze-back cages
• Behavioral conditioning or training

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Handling NHPs

• ABSL-2 required
• Restraint required
• squeeze-back cages
• pole and collars
• primate chairs
• Cover long hair and remove all jewelry.

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Protection of NHP workers

• Gloves
• appropriate to use
• Gowns/coveralls
• Face protection
• goggles
• face shield
• surgical mask or respirator
• Other
• head and beard covers
• shoe covers/boots

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NHP Facilities Access Control and Staff Training

• Training (more extensive periodic)
• Personnel must enroll in med surveillance
  program
• Restricted/controlled access
• Animal BSL2 containment conditions
• Written emergency response plans

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Laboratory Animal Allergy

• 10 of those without previous history will
  develop allergy to lab animals
• 70 of those with pre-existing allergies will
  develop a new allergy
• Overall risk is 30

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Allergies

• Symptoms---upper respiratory irritation, can
  progress to asthma and anaphylaxis
• Screen with personal and family history

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Allergy Screening

• Personal history of allergies/ atopy/eczema
  strongly associated with increased risk
• Family history of allergy also important
• Only test in case of pre-existing symptoms when
  patient plans on working with that species
• Periodic screen by history for development of new
  allergies in high risk patients

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Common allergy sources

• Rats/ Mice--major allergens in urine/saliva
• Cats--sebaceous glands, hair, saliva
• Dogs--saliva, hair, skin
• Rabbits--fur,saliva, urine
• Birds--droppings
• Bedding
• Note non occupational sources of exposure

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Prevention of Lab Animal Associated Allergies

• Employee selection
• Biosafety cabinets
• Filter top cages
• Ventilated cage racks

• Choice of bedding
• Animal density
• Proper humidity
• Personal protective equipment

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Treatment of Lab Animal Associated Allergies

• Prevention is preferred
• Education of employees
• Proper use of personal protective equipment
• Re-assign employees when needed
• Medical treatment to reduce symptoms

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Risk Factors for Development of LAA

• Exposure to allergens
• duration
• frequency
• intensity
• Previous allergic conditions
• Other predisposing conditions
• illness
• immunocompromised
• pets

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Routes of exposure for LAAs
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Routes of exposure for LAAs
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LAA Exposure Control

• Engineering controls
• enclosure
• dilution ventilation
• Administrative controls
• reduce time with animals
• reduce density of animals
• housekeeping practices
• Personal protective equipment
• respirators and clothing
• Medical surveillance (screening and ongoing
  monitoring)

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LAA Exposure Control
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Administrative Considerations

• The key elements in the review and approval of
  animal experiments
• Institutional Animal Care and Use Committee
  (IACUC)
• Institutional Biosafety Committee (IBC)
• Environmental Health and Safety/ Biosafety
  Officer (BSO)
• Director of Veterinary Services
• Communication and coordination is important
• work together to review protocols

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Administrative Considerations

• Consider unique aspects of each protocol
• IACUC/IBC assignment of
• location
• containment level
• All handlers must be informed of
• medical surveillance requirements
• specific risks of species, agent
• signs/symptoms of infection
• containment protocol selected
• emergency response procedures