Common Problems in Laboratory Animals

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Common Problems in Laboratory Animals

• Nirah H Shomer, DVM PhD Dip. ACLAM

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Barbering

• Normal grooming behavior
• Usually, but not always, one unmarked barber
• Barber is usually dominant
• Usually harmless, but can precipitate
  conjunctivitis, ulcerative dermatitis

Barber
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Periocular irritation (secondary to barbering)
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Fight Wounds

• Characteristic wound locations on fleeing mice
• Tails, rear feet, genitals

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There is typically a dominant aggressive mouse

• Even if you remove the aggressor, another mouse
  may take his place.
• Fights are almost exclusively between males
• In some strains, even littermates raised together
  will fight (BALB/c, SJL)

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Fight wounds (fatal)

• Mice may die, rapidly, of septicemia
• Treat with broad spectrum antibiotics

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Ulcerative Dermatitis
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• Ulcerative
• Dermatitis

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Skin lesions

• Etiology Pattern Treatment
• Barbering Normal grooming any (same all
  mice) remove barber
• Fight Wounds Fighting tail, back,
  genitals remove aggressor
• Ulcerative Dermatitis Unknown nape of neck,
  none under arms ointments
• pain drugs
• Linked to C57BL 2 infection
  common antibiotics

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Emaciation

• Look for underlying cause
• Report objectively using Body Condition Score

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These are littermates. What is the mouse on the
right?

• Runt
• What should you check for?

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Malocclusion

• Rodent incisors grow continuously
• Can be maintained by weekly clipping

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Malocclusion is heritable
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Diarrhea

• Mouse diarrhea is usually very subtle
• All you see is bedding stuck to pellets and anus

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Rabbit feces

• Normal pellets Diarrhea
• True or False diarrhea is normal in rabbits
• False they do have night feces, cecotrophs,
  which are usually eaten directly from the anus

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Hamster with wet tail

• Bacterial infection (Lawsonia intracellularis)-
  proliferative ileitis
• Clostridial overgrowth (spontaneous, age- or
  stress-related)
• Antibiotic toxicity (causes clostridial
  overgrowth)

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Rectal Prolapse

• Rectum protrudes through anus
• Associated with diarrhea, Helicobacter infection

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Seizures
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Dystocia(difficult birth)

• Dam neonate pup from last litter

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Whats wrong with this mouse?
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Inguinal Hernia

• Protrusion of an organ (e.g. gut) through a
  natural opening (e.g. inguinal canal) or
  unnatural rent (e.g. diaphragmatic rupture) in a
  body wall.
• Note that this mass is reducible.

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Why is this rabbit matted?

• Obesity

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Hunched Scruffy

• Non-specific sign indicating mouse is too ill to
  groom itself.

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Tumor

• Size/dimensions 1.5x2.5x2.5cm
• Shape irregular/lobulated
• Location scapular/right flank
• Color mottled
• Texture firm/fluctuant
• Ulceration ulcerated

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Zymbals Gland Tumor
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Circling
Head Tilt
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Porphyrin staining

• Pigment comes from Harderian glands
• Increased in stress, respiratory disease,
  sialodacryoadenitis virus (SDA) infection
• Prominent in rats and gerbils, not in mice
• Found around eyes, nares, paws (from grooming
  face)

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Conjunctivitis

• Inflammation of the conjunctival tissues aka
  pink-eye. Usually bacterial, may not respond well
  to antibiotics.

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Proptosis

• Bulging or protruding eye
• Causes include tumor, abscess, retroorbital
  bleed/hematoma, glaucoma
• Secondary effects include keratitis, loss of eye

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Paralysis

• Theilers mouse encephalomyelitis virus (TMEV
  strain GD VII)
• Spontaneous or iatrogenic trauma
• Experimental Allergic Encephalitis (EAE)
  (multiple sclerosis model)

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Find the barber

• X

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Pop Quiz
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1. Whats wrong with these mice?
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2. List all rule-outs for this condition
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3. Describe this mouse
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4. Which mouse should you remove from the cage,
and why?

• 1 2 3
  4

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5. Whats wrong with this rabbit?
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6. What is wrong with this mouse?
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7. Name the condition.
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8. What is wrong with this rat?
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1. Whats wrong with these mice?

• Barbering

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2. List rule-outs for this condition

• Fight wounds
• Ectromelia (pox virus)
• Footpad injection (swollen feet)
• Tail bleeding/overheating (tail lesions)

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3. Describe this mouse

• Emaciated
• Also nude (but this is not a problem)

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4. Which mouse should you remove from the cage,
and why?

• 1 2 3
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• These are fight wounds. Remove the aggressor.
• Hint he is the one without lesions

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5. Whats wrong with this rabbit?

• Malocclusion

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6. What is wrong with this mouse?

• Tumor. Most common tumor in this area?
• Mammary tumor

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7. Name the condition.

• Head tilt

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8. What is wrong with this rat?

• Reddish discharge around eyes
• What is this substance?
• Porphyrin

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The End
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Whats wrong with this frog?

• normal Xenopus
• Severe emaciation
• Skin lesions

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Whats wrong with this frog?

• Emaciation
• chronic kidney disease
• Mycobacteria spp. chronic bacterial infection,
  zoonotic

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Skin lesions

• No pattern

• Pseudocapillaroides xenopi (nematode parasite)

• Fungal infection

• Discoloration

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Mastitis
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E. coli Mastitis in a ferret