Animals and Allergens

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Animals and Allergens
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Risk Assessment for Work with Research Animals

• Risks associated with the research agent used in
  the animal
• chemical, physical, biological
• Risks associated with the species of animal used
• zoonotic agents
• Risks associated with animal maintenance
• ergonomic factors, bites, scratches, allergens

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Risks Associated with the Agent Used

• Chemical agents
• carcinogens, mutagens
• toxic chemicals
• anesthetics
• Physical agents
• radiation
• heat
• sound

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Risks Associated with the Agent Used

• Potentially biohazardous agents
• deliberate use of an infectious agent in animals
  for research purposes
• maintenance of infected animal for duration of
  experiment
• sacrifice, necropsy and harvesting of
• agent or infected tissue

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Transmission of Biohazards During Work with
Animals

• Airborne
• Release of infectious aerosols by animal by
  sneezing, coughing
• Release during nasal infection or aerosol
  challenge
• Aerosolization from bedding and excreta
• During surgical procedures
• During birthing

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Transmission of Biohazards During Work with
Animals

• Direct Inoculation
• Needlesticks during injection/inoculation process
• Bites and scratches from infected animal

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Transmission of Biohazards During Work with
Animals

• Direct exposure of mucous membranes
• (by splash or splatter)
• During surgical procedures
• During injection
• During necropsy

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Transmission of Biohazards During Work with
Animals

• Indirect transmission and ingestion
• From contaminated hands or gloves to mouth
• Facial contamination directly from animal
• Transfer of parasites by animal handling
• Indirect transmission with eye or mucous
• membrane exposure
• Dust from bedding
• Splash during cage washing
• Dirty environment

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Risk Reduction Containment of Infectious Agent

• Containment must include
• Primary containment
• Enclosed filtered caging system
• Biosafety cabinets
• Safety equipment
• PPE
• Secondary containment
• The containment facility
• Negative pressurization
• Nonrecirculated air supply
• Ventilation must consider wellbeing of animal
  

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Containment Caging Systems

• No Containment
• Open (standard) cage
• Some Containment
• Filter top cage
• (microisolator cage)
• Full Containment
• Fully enclosed in
• ventilated rack

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Containment Caging Systems

• Microisolator Cage
• works like a Petri dish
• open gaps around lid edge allow limited air
  exchange
• may lead to more labor intensive husbandry due to
  moisture and ammonia buildup

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Containment Caging Systems

• Individual cages sealed into rack with supplied
  air under negative pressure
• Both supply and exhaust usually HEPA filtered
• Ventilation must control humidity and buildup of
  ammonia

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Containment Caging Systems

• Can install cages in class III biosafety cabinet
• Cages are completely contained with glove port
  access
• Very motion-limiting
• Transfer in and out may be an issue

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Containment Caging Systems

• BioBubble (Ft. Collins, CO) makes soft-wall
  ventilated enclosures
• Can be containment or barrier style
• Large equipment can be surface-mounted in wall

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Special Animal Housing Situations

• Barrier colonies
• Special breeds - often immunocompromised,
  fragile, expensive (SCID-Hu, nude athymics)
• Transgenics - often even more fragile and
  expensive (knockouts, microinjected, combos)
• Specific pathogen-free (SPF) - bred and raised to
  be missing certain specific microorganisms
• Isolation colonies
• Extensive SPFs and defined flora animals
• Gnotobiotes (an entirely different animal!)

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Zoonoses

• Zoonotic disease A disease of animals that can
  be transmitted under natural conditions and cause
  disease in humans
• Wild caught animals most hazardous
• Random source animals (e.g., from a pound) are
  also a risk
• Purpose bred animals pose least risk

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Some Animals and Their Zoonoses

• Disease
• Herpes B virus
• Q fever
• Hantavirus
• Rabies
• Tuberculosis
• Toxoplasmosis
• Psittacosis
• Avian influenza

• Animal
• Macaque monkeys
• Sheep
• White mouse
• Dogs, cats, skunks, raccoons, bats
• Cattle, NHP
• Cats
• Parrots, macaws
• Chickens

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Rodent Zoonoses

• Rat bite fever (Streptobacillus moniliformis,
  Spirillum minus)
• transmission direct contact (bites)
• Lymphocytic choriomeningitis (LCM, a virus)
• transmission inhalation
• Leptospirosis (Leptospira spp.)
• transmission inhalation
• Others include ringworm (fungal), scabies (mites,
  an ectoparasite)

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Transmission of Zoonoses

• Enteric route (fecal/oral)
• Salmonella, Shigella, Campylobacter,
• Giardia, Toxoplasma, Cryptosporidium,
• Entamoeba, Hepatitis A
• Respiratory route
• Q fever, Chlamydia, Measles
• Skin contact
• Ringworm (Tinea), Measles, Monkeypox

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Control of Zoonoses

• Get information on species and agent
• Quarantine animals prior to use
• Use Engineering controls
• facility construction and
• secondary barriers
• Consider the need for containment caging

• Use Administrative controls
• written SOPs and
• manuals
• Use PPE
• additional protection for
• worker
• Practice good facility and personal hygiene
• Provide staff training

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Laboratory Acquired Allergies (LAA)

• Significant occupational disease
• Affects gt30 of all personnel working with
  animals
• No minimum safe exposure levels to allergens have
  been established
• Animal allergens found in hair, dander, urine,
  saliva, serum
• fel-d-l cat allergen (in saliva and thus on skin)
  is one of the strongest allergens known for humans

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Sources of Exposure to LAA

• Hair and dander shed from animal
• Urine and feces dried in bedding
• Particulates shed from bedding material
• Animal saliva

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Routes of Exposure to LAA

• Inhalation of airborne allergens
• during cage changing
• during animal handling
• Skin or eye contact
• usually indirect by touching skin, eyes
• Percutaneous exposure
• animal bites (saliva)

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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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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