L2: Flea Allergy (Marsella) Flashcards
most common external parasite
fleas
most common skin disease
flea allergy dermatitis
flea biology
- belongs to order siphonoptera
- blood sucking insect
- chitin exoskeleton with hairs and spines
- laterally compressed body with no wings
- suctorial mouthparts and combs
- resilient to high pressure and cold
- males smaller
why can fleas jump so high
elastic protein resillin above hind legs
most common flea on dogs and cats**
Ctenocephalides felis
human flea
Pulex irritans
stick tight fleas
- fleas in birds/poultry
- literally stick to skin of dogs/cats
- easily seen on margin of pinnae
Ctenocephalides felis: transmission of dz
- plague
- murine typhus and tularemia
- Dipylidium caninum
- Cat scratch fever
- NOT host specific (occurs on many wildlife)
Ctenocephalides felis: life cycle***
- adult spends entire life on host
- 21 days = ideal life cycle***
- doesn’t like high altitude or low humidity
- eggs laid after blood meal and seed environment
flea eggs resistant to all insecticides except:
IgR
Ctenocephalides felis: larva
- in environments
- small hairs help wrap around carpet
- molt twice
- don’t like light or too much heat
- rudimental eyes
- limited movement
- like dark, warm areas
- eat flea feces
Ctenocephalides felis: cocoon or pupa**
- most resistant stage**
- difficult to remove vacuuming
- can be dormant for months
Ctenocephalides felis: emergence of young fleas triggered by:
- vibtration
- body temp
- low conc. CO2
adults compose what percent of total flea population?
5%
T/F: not all animals exposed to fleas develop allergy**
T
predisposing factors to flea allergy
- lack of exposure neonatally or at young age
- intermittent exposure
- small amounts
- atopy
Mixed Hypersensitivity***
Type I hypersensitivity (IgE mediated)
Type IV: delayed (cell mediated) hypersensitivity
Cutaneous basophil hypersensitivity
mixed pathogenesis has consequences on diagnostic tests and therapy
CS of FAD
- no breed/sex
- 1-5yrs onset
- papule = primary lesion
- self trauma with ABSENCE of fleas
- worsens over time with waxing/waning of signs, seasonal
- lesions in back half
- distr.: lower back , perineum, tailhead, hind legs, umbilical region
- alopecia, lichenification, hyperpigmentation
- 2ary staph infection common
3 most pruritic diseases in dogs**
FAD
Scabies
Food allergy
Feline FAD char. by:
- miliary dermatitis
- feline symmetrical alopecia
- eosinophilic granuloma complex
- plaques in inguinal area
Dx of Feline FAD
- CS and R/O’s
- presence of fleas or feces
- carrier animals
- tapeworm history
- Intradermal skin testing (neg. doesn’t rule out!)
- whole flea antigen
histopath fo dx of FAD
- non-specific (tells you there is an allergic rxn but not what kind)
- superficial perivascular dermatitis with eosinophils
Dx of FAD
positive response to elimination of fleas**
clinical appearance
intradermal allergy testing or blood testing
FAD therapy
- varies with pet(s) & env.
- env. must be considered in Florida**
- chemical adulticides on pets
- repellents in allergic dogs
- IGR’s
- combo/rotation of products (pick products that work via different MOA)
- all year round
- no immunotherapy
- kill fleas!
- tx pyoderma
- antipruritic therapy
- antihistamines? (not very effective)
