Parasitic diseases Flashcards
List the 4 main arachnid ectoparasites of small animals
- demodecosis
- sarcoptic mange (scabies)
- cheyletiellosis
- trombiculariasis
Outline trombiculariasis:
name
signs
Tx
- (Neo) Trombicula autumnalis
- SIGNS: Larvae just visible, strictly seasonal (July-Sept-Oct), Asymptomatic –> severe pruritis
- Tx (NL) - fipronil
Describe the appearance of a dog with Cheyletiella
thin, greasy, oily, white flecks, alopecia,
- EGG attaches to hair shaft
- CS - scaling (walking dandruff), pruritus (mild >severe), primarily dorsal trunk, miliary dermatitis (Cats)
Which species can Cheyletiella affect? 3
cats, dogs, rabbits
Which Cheyletiella species infect the skin? 3
- C. blakei
- C. yasurgi
- C.parasitovorax
T/F: Cheyletiellosis is zoonotic
True
Tx - Cheyletiellosis
> 6 weeks usually, often difficult
- in contact dogs, cats and rabbits
- NL but can use amitraz, fripronil, selamectin, moxidectin, ivermectin, selenium sulphide shampoo,
Define Demodecosis
an inflammatory parasitic skin disease characterised by the presence of larger than normal numbers of demodectic mites (as normally a commensal)
List the demodex species in dogs, cats and horses
DOG - D.canis, (D. injai, short-bodied mite)
CAT - v rare, (D.cati, D.gatoi)
HORSE - v rare.
T/F: demodecosis is zoonotic
True
CS - demodecosis
- prominent hair follicles
- alopecia
What are the 3 main manifestations of canine demodecosis
- juvenile onset (up to 6 months), localised - often recovers spontaneously
- juvenile onset, generalised - inherited predisposition, Great Danes and SBTs
- adult onset, generalised or localised, usually > 2 years old, suspect underlying immunosuppression (drugs - GCs, endocrinopathy, neoplasia)
Tx - canine demodecosis (generalised cases)
- expect minimum 12 weeks tx
- minotr (CS and repeat scrapes/plucks)
- AVOID steroids
- manage client expectations
What species are affected by sarcoptic mange?
DOGS - common
CATS - rare, usually immunosuppressed and exposed
HORSES - very rare, UK notifiable
Define canine scabies
An intensely pruritic transmissible infestation of dogs caused by Sarcoptes scabei (var. canis?)
What are the 3 commonest CS of FAD?
- hair loss
- inflammation
- self-trauma
What are the main mechanisms of ectoparasite hypersensitivity?
- IgE mediated (MC activation)
- Delayed cell mediated: basophil hypersensitivity, TH1 (macrophages), TH2 (lymphocyte/eosinophil)
What antigens may be responsible for ectoparasite hypersensitivity?
- saliva *
- cuticule
- excreted metabolites/enzymes/toxins
- faeces
T/F: flea infestation in non-FAD animals is unlikely to cause skin lesions
True
What animals develop flea bite hypersensitivity?
- age usually 3-5 years
- breed predisposition?
- AD dogs predisposed?
- seasonal or non-seasonal (especially house cats)
Dx - flea bite hypersensitivity
- Hx and signs
- presence of fleas or flea faeces
- response to therapy
- allergy testing
How can you allergy test for flea bite hypersensitivyt?
- Intradermal testing (by whole body extract) causing immediate and delayed reactions. N.b. proportion of salivary gland in this is minimal therefore possible diluted response.
- Serology (saliva-specific)
How can flea bite hypersensitivity be managed?
- flea control regimen * (think of all possible sources)
- Antipruritic/anti-inflammatory medications (GCs, anti-histamines, EFA)
- Allergen-specific immunotherapy (whole flea extract is ineffective, salivary antigen rush protocol promising but is unavailable)
