1. Common Problems in Laboratory Animals
Nirah H Shomer, DVM PhD Dip. ACLAM

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

3. Periocular irritation (secondary to barbering)

4. Fight Wounds Characteristic wound locations on fleeing mice:
Tails, rear feet, genitals

5. 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)

6. Fight wounds (fatal) Mice may die, rapidly, of septicemia
Treat with broad spectrum antibiotics

7. Ulcerative Dermatitis

8. Ulcerative
Dermatitis

9. 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

10. Emaciation Look for underlying cause
Report objectively using Body Condition Score

11. These are littermates. What is the mouse on the right?
Runt
What should you check for?

12. Malocclusion Rodent incisors grow continuously
Can be maintained by weekly clipping

13. Malocclusion is heritable

14. Diarrhea Mouse diarrhea is usually very subtle
All you see is bedding stuck to pellets and anus

15. 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

16. Hamster with “wet tail”
Bacterial infection (Lawsonia intracellularis)- proliferative ileitis
Clostridial overgrowth (spontaneous, age- or stress-related)
Antibiotic toxicity (causes clostridial overgrowth)

17. Rectal Prolapse Rectum protrudes through anus
Associated with diarrhea, Helicobacter infection

18. Seizures

19. Dystocia (difficult birth)
Dam neonate pup from last litter

20. What’s wrong with this mouse?

21. Note that this mass is reducible.
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.

22. Why is this rabbit matted?
Obesity

23. “Hunched” “Scruffy”
Non-specific sign indicating mouse is too ill to groom itself.

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

25. Zymbals Gland Tumor

26. Circling
Head Tilt

27. 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)

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

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

30. Paralysis Theiler’s mouse encephalomyelitis virus (TMEV strain GD VII)
Spontaneous or iatrogenic trauma
Experimental Allergic Encephalitis (EAE) (multiple sclerosis model)

31. Find the barber X

32. Pop Quiz

33. 1. What’s wrong with these mice?

34. 2. List all rule-outs for this condition

35. 3. Describe this mouse

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

37. 5. What’s wrong with this rabbit?

38. 6. What is wrong with this mouse?

39. 7. Name the condition.

40. 8. What is wrong with this rat?

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

42. 2. List rule-outs for this condition
Fight wounds
Ectromelia (pox virus)
Footpad injection (swollen feet)
Tail bleeding/overheating (tail lesions)

43. 3. Describe this mouse
Emaciated
Also nude (but this is not a problem)

44. 4. Which mouse should you remove from the cage, and why?
These are fight wounds. Remove the aggressor.
Hint: he is the one without lesions

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

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

47. 7. Name the condition.
Head tilt

48. 8. What is wrong with this rat?
Reddish discharge around eyes
What is this substance?
Porphyrin

49. The End

50. What’s wrong with this frog?
normal Xenopus
Severe emaciation
Skin lesions

51. What’s wrong with this frog?
Emaciation
chronic kidney disease
Mycobacteria spp. chronic bacterial infection, zoonotic

52. Skin lesions No pattern Pseudocapillaroides xenopi (nematode parasite)
Fungal infection
Discoloration

54. Mastitis

55. E. coli Mastitis in a ferret