Common Problems Common Problems in Laboratory Animalsin Laboratory Animals

Nirah H Shomer, DVM PhD Dip. ACLAMNirah H Shomer, DVM PhD Dip. ACLAM

BarberingBarbering

• Normal grooming behaviorNormal grooming behavior

• Usually, but not always, Usually, but not always, one unmarked barberone unmarked barber

• Barber is usually dominantBarber is usually dominant

• Usually harmless, but can Usually harmless, but can precipitate conjunctivitis, precipitate conjunctivitis, ulcerative dermatitisulcerative dermatitis

BarberBarber

Periocular irritation Periocular irritation (secondary to barbering)(secondary to barbering)

Fight WoundsFight Wounds

Characteristic wound locations on fleeing mice:Characteristic wound locations on fleeing mice:

• Tails, rear feet, genitalsTails, rear feet, genitals

There is typically a dominant aggressive mouseThere is typically a dominant aggressive mouse

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

Fight wounds (fatal)Fight wounds (fatal)

• Mice may die, rapidly, of septicemiaMice may die, rapidly, of septicemia

• Treat with broad spectrum antibioticsTreat with broad spectrum antibiotics

Ulcerative DermatitisUlcerative Dermatitis

Ulcerative Ulcerative

DermatitisDermatitis

Skin lesionsSkin lesions

EtiologyEtiology PatternPatternTreatmentTreatment

BarberingBarbering Normal groomingNormal grooming any (same all mice)any (same all mice) remove barberremove barber

Fight WoundsFight Wounds Fighting Fighting tail, back, genitalstail, back, genitals remove remove aggressor aggressor

Ulcerative DermatitisUlcerative Dermatitis Unknown Unknown nape of neck, nape of neck, nonenoneunder armsunder arms ointmentsointments

pain drugspain drugs

Linked to C57BLLinked to C57BL 2° infection common2° infection common antibioticsantibiotics

EmaciationEmaciation• Look for underlying causeLook for underlying cause

• Report objectively using Body Condition ScoreReport objectively using Body Condition Score

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

What should you check for?What should you check for?

MalocclusionMalocclusion

• Rodent incisors grow continuously Rodent incisors grow continuously

• Can be maintained by weekly clippingCan be maintained by weekly clipping

Malocclusion is heritableMalocclusion is heritable

DiarrheaDiarrhea

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

Rabbit fecesRabbit feces

Normal pellets DiarrheaNormal pellets Diarrhea

True or False: diarrhea is normal in rabbitsTrue or False: diarrhea is normal in rabbits

False: they do have “night feces”, cecotrophs, which are usually eaten directly from the False: they do have “night feces”, cecotrophs, which are usually eaten directly from the anusanus

Hamster with “wet tail”Hamster with “wet tail”

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

Rectal ProlapseRectal Prolapse

• Rectum protrudes through anusRectum protrudes through anus

• Associated with diarrhea, Associated with diarrhea, HelicobacterHelicobacter infection infection

SeizuresSeizures

DystociaDystocia(difficult birth)(difficult birth)

DamDam neonateneonate pup from pup from last litterlast litter

What’s wrong with this mouse?What’s wrong with this mouse?

Inguinal HerniaInguinal Hernia

Protrusion of an organ (e.g. gut) through a natural opening Protrusion of an organ (e.g. gut) through a natural opening (e.g. inguinal canal) or unnatural rent (e.g. diaphragmatic (e.g. inguinal canal) or unnatural rent (e.g. diaphragmatic rupture) in a body wall. rupture) in a body wall.

Note that this mass is reducible.Note that this mass is reducible.

Why is this rabbit matted?Why is this rabbit matted?ObesityObesity

““Hunched” “Scruffy”Hunched” “Scruffy”

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

TumorTumor

• Size/dimensionsSize/dimensions 1.5x2.5x2.5cm1.5x2.5x2.5cm

• ShapeShape irregular/lobulatedirregular/lobulated

• LocationLocation scapular/right flankscapular/right flank

• ColorColor mottledmottled

• TextureTexture firm/fluctuantfirm/fluctuant

• Ulceration Ulceration ulceratedulcerated

Zymbals Gland TumorZymbals Gland Tumor

Porphyrin stainingPorphyrin staining

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

ConjunctivitisConjunctivitis

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

ProptosisProptosis

• Bulging or protruding eyeBulging or protruding eye

• Causes include tumor, abscess, retroorbital Causes include tumor, abscess, retroorbital bleed/hematoma, glaucomableed/hematoma, glaucoma

• Secondary effects include keratitis, loss of eyeSecondary effects include keratitis, loss of eye

ParalysisParalysis

• Theiler’s mouse encephalomyelitis virus (TMEV strain GD VII)Theiler’s mouse encephalomyelitis virus (TMEV strain GD VII)

• Spontaneous or iatrogenic traumaSpontaneous or iatrogenic trauma

• Experimental Allergic Encephalitis (EAE) (multiple sclerosis model)Experimental Allergic Encephalitis (EAE) (multiple sclerosis model)

Find the barberFind the barber

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Pop QuizPop Quiz

1. What’s wrong with these mice?1. What’s wrong with these mice?

2. List all rule-outs for this 2. List all rule-outs for this conditioncondition

3. Describe this mouse3. Describe this mouse

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

1 2 3 41 2 3 4

5. What’s wrong with this rabbit?5. What’s wrong with this rabbit?

6. What is wrong with this 6. What is wrong with this mouse?mouse?

7. Name the condition.7. Name the condition.

8. What is wrong with this rat?8. What is wrong with this rat?

1. What’s wrong with these mice?1. What’s wrong with these mice?BarberingBarbering

2. List rule-outs for this condition2. List rule-outs for this condition

• Fight woundsFight wounds

• Ectromelia (pox virus)Ectromelia (pox virus)

• Footpad injection (swollen feet)Footpad injection (swollen feet)

• Tail bleeding/overheating (tail lesions)Tail bleeding/overheating (tail lesions)

3. Describe this mouse3. Describe this mouse

• EmaciatedEmaciated

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

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

1 2 3 1 2 3 44These are fight wounds. Remove the aggressor.These are fight wounds. Remove the aggressor.

Hint: he is the one without lesionsHint: he is the one without lesions

5. What’s wrong with this rabbit?5. What’s wrong with this rabbit?MalocclusionMalocclusion

6. What is wrong with this mouse?6. What is wrong with this mouse?Tumor. Most common tumor in this area=?Tumor. Most common tumor in this area=?

Mammary tumorMammary tumor

7. Name the condition.7. Name the condition.Head tiltHead tilt

8. What is wrong with this rat?8. What is wrong with this rat?Reddish discharge around eyesReddish discharge around eyes

What is this substance?What is this substance?

PorphyrinPorphyrin

The End

What’s wrong with this frog?What’s wrong with this frog? normal normal XenopusXenopus

Severe emaciationSevere emaciation

Skin lesionsSkin lesions

What’s wrong with this frog?What’s wrong with this frog?EmaciationEmaciation

• chronic kidney diseasechronic kidney disease• Mycobacteria spp. chronic Mycobacteria spp. chronic

bacterial infection, bacterial infection, zoonoticzoonotic

Skin lesionsSkin lesions•No patternNo pattern

•Pseudocapillaroides Pseudocapillaroides xenopixenopi (nematode (nematode parasite)parasite)

•Fungal infectionFungal infection

•DiscolorationDiscoloration

MastitisMastitis

E. coliE. coli Mastitis in a ferret Mastitis in a ferret