Ruminant Dermatology, Pt. 2 Flashcards
Where are screwworm infestations most common?
SOUTH - Texas, Florida, Mississippi
- seen in horses, dogs, and deer
What is miasis?
fly strike - infestation with maggots that eat dead flesh (flies) or live flesh (screwworms)
How do animals with miasis present? How is it treated?
sick, depressed, maggots and odor observed
- clean and debride wound
- antibiotics
- systemic dewormer + fly spray
What conditions predispose to miasis?
- docked tails - decreased wound around tail + wound
- moist and unhygienic environments
- wooly breed sheep (Marinos) - can hide flies under wool and maintain a moist environment
What extreme measure has been taken decrease sheep death to miasis?
mulesing - removal of strips of wool-bearing skin from around the rear
- wool around here typically retains feces and urine, which attract flies
What ectoparasite is seen in this sheep’s coat?
sheep ked - wingless fly susceptible to Ivermectins
What is Stephanofilariasis?
infection caused by parasite carried by the horn fly presenting with ventral midline and udder dermatosis in adult cows
- common, not very serious
What are the 2 species of warbles (Hypodermiasis) that affect cows? Where are each found?
- H. bovis - northern US, migrates to spinal cord —> killing with OP can cause downers or bloat DO NOT TREAT IN WINTER
- H. lineatum - northern and southern US, migrates to esophagus
bee-like, hairy adults live for 1 week
What is the lifecycle of warbles like?
- eggs laid on extremities in spring and summer
- eggs hatch and larvae penetrate the skin and migrate to the spinal cord or esophagus to over-winter for 2-4 months —-> DO NOT TREAT
What is the cut-off to treating warble infections?
DO NOT TREAT November 15th to March 15th (Ivermectin)
- killing larvae in the spinal cord and esophagus can cause paralysis or bloat
Cattle warbles:
hypodermiasis - “blow holes” where larvae penetrate the skin and eventually return Jan-Feb and after March
How do cattle present with copper deficiencies?
lighter colored coats
- treat with copper supplementation
When are fleas most commonly a problem? Where do infestations most commonly originate? What signs are associated with infestation?
summer
barn cats —> fleas are not species-specific (Ctenocephalides felis)
rubbing, scratching, chewing, anemia, emaciated calves
What must treatment of fleas focus on?
treatment of affected and unaffected animals AND the environment
- insecticides and insect-growth regulators
- removal of staw bedding
- treat any barn cats
- remove feral cats from premises
What is the most common cause of ringworm in cattle? How is it transmitted?
Trichophyton verrucosum
ZOONOTIC - direct contact with infected animal or fomite (incubates for 1-6 weeks)
How do ringworm lesions progress? Where are lesions most commonly found?
- thickened and scaled skin = circular and crusty
- hair loss as hairs are invaded and break off
- expand for 4-8 weeks and resolve with immune response
head, neck - alopecia, scaling
Ringworm:
- halter is a common fomite!
- begins with crusting
What groups of cattle are commonly infected with Ringworm?
show cattle —> in contact with multiple other cows and bulls regularly
What are 5 predisposing factors to ringworm?
- age - young animals more susceptible
- immunity - prior exposure improves host resistance
- environment - more common in the winter, crowding
- remains in the environment for years
- nutrition - poorly conditioned animals are more susceptible
What fungus commonly infects show lambs? Why is it more common in show lambs?
Trichophyton —> contagious to humans!
frequent washing removes lanolin in the wool that usually protects lamb
What species of ringworm most commonly affects swine? What age is most susceptible? What predisposes?
Microsporum nanum —> ubiquitous in the environment + ZOONOTIC
adults
poor sanitation and high humidity
What is the most common cause of ear warts in cattle? How are they treated?
contaminated ear tag equipment
vaccination +/- cryotherapy and debulking
What clinical sign is associated with photosensitization? How is it treated?
sloughing of light-colored hair areas
remove cause (photodynamic/hepatotoxic plants) and sunlight
Photosensitization:
light colored areas affected
What are the most common signs of Dermatophilosis? What areas are specifically affected in llamas, cattle, sheep, and goats?
roughened coats with paint-brush lesions when plucked - painful and NOT pruritic
- LLAMAS = not pruritic
- CATTLE = back, sides, neck
- SHEEP = coronary band
- GOATS = tail and ears of kids, muzzle, dorsum, scrotum, and legs of adults
How is Dermatophilosis diagnosed?
- typical presentation with no pruritis
- smear of scabs or skin biopsy show train tracks of microorganisms
How does caseous lymphadenitis present?
- unilateral LN swelling filled with caseous (very contagious) material
- internal LN swelling causes systemic signs
What causes contagious echthyma? What ruminants are most commonly affected? What can cause outbreaks?
sore mouth, orf = Parapox virus —> ZOONOTIC
sheep, goats, llamas
persists for years in scabs/soil —> lambing/kidding
What clinical signs are associated with orf?
- lesions most common on lips, muzzle, oral cavity, udder, and coronary bands (MUCOCUTANEOUS JUNCTIONS)
- painful —> dams won’t let offspring nurse —> starvation in offspring
- affected offspring can infect udders
How is orf diagnosed?
- presumptive diagnosis based on signs
- skin biopsy and histopath
How is orf treated?
- usually self-limiting within 3 weeks
- TLC for affected young
What is the depicted insect that can be found in the wool of sheep?
a. flytick
b. ked
c. wool spider
B
