Demodex Consensus Statement Flashcards
Most likely cause of generalized demodicosis in young dogs
Temporary immune alteration
Usually CELL-MEDIATED deficiency
Most likely cause of generalized demodicosis in older dogs
Immunosuppressive conditions, treatments
Which demodex species can infect healthy cats
Demodex gatoi
T or F: a single gene mutation is responsible for juvenile generalized demodicosis
False. It is genetic, but likely multiple genes
Which is longer: Demodex canis or Demodex injai
Injai is longer!
Which is longer: Demodex cati or Demodex gatoi
Cati. Demodex gatoi is short
Which breeds are predisposed to Demodex injai
Terriers. Excessively greasy
Clinical sign of Demodex gatoi
Truncal pruritus
Best diagnostic for demodex
Deep skin scrape
But can do trichograms, tape strips, examine exudate too!
T or F: if you find a single mite on a deep skin scrape, that is confirmatory of clinically relevant demodicosis
False. But more than 1 does confirm clinical relevance
T or F: A dam or sire may be breed again if one of their puppies has generalized demodicosis
False. Dogs with generalized demodicosis and their parents should not be bred.
Monitoring protocol for a dog with generalized demodicosis
Skin scraping q1month until 2 negative scrapings
How long should treatment continue for demodicosis
At least 4 weeks past 2nd negative monthly skin scrape
Topical treatment protocol for dogs with demodicosis
Amitraz 0.025-0,05% weekly.
Clip long haired animals
Oral ivermectin, moxidectin, milbemyxin oxime protocol for demodicosis in dogs
Ivermectin 0.3-0.6mg/kg PO q24h
Moxidectin 0.3-0.5 mg/kg PO q24h
**START AT LOWER DOSE AND TAPER UP- in case sensitivity to macrocyclic lactones (toxicity)
Milbemycin oxime 1-2 mg/kg PO q24h
SC doramectin protocol for demodicosis in dogs
0.6 mg/kg SC q1w
T or F: Topical moxidectin/imidacloprid should be considered for mild-moderate cases of
canine demodicosis
True
Topical treatments for cats with demodicosis
2% Lime sulfur dip weekly
Amitraz bath 0.0125% weekly
OR
Weekly moxidectin/imidacloprid spot on
T or F: demodex is a commensal of many mammals
True.
Transmitted from dam to puppies within first days of life
What type of immunity is deficient in dogs with juvenile demodicosis?
Cell mediated!
*Low CD4 T cells
*Low TNFa (proinflam)
*Increased IL-2, IL-5, IL-6, IL18, IL-10, TGF-b (immunosuppressive)
Normal humoral response
Are MHC class II molecules upregulated or downregulated on keratinocytes of dogs with demodex
Upregulated
Which TLR is increased in dogs with demodicosis
TLR2– recognizes chitin
T or F: Most dogs with juvenile generalized demodicosis have recurrence once it is treated
FALSE. Recurrence is very uncommon
Likely a TEMPORARY immune aberration to allow mites to overpopulate
Diseases/drugs in adult dogs that predispose them demodicosis
*Leishmaniosis
*HAC
*Hypothyroidism
*Neoplasia
*Babesiosis
*Ehrlichiosis
*Glucocorticoids
*Chemotherapy
Diseases in adults cats that predispose them to demodicosis
*FIV
*Xanthoma
*Diabetes mellitus
Localized form with BISC
Breeds predisposed to generalized demodicosis
*American Staffordshire terrier
*Staffordshire bull terrier
*Chinese Shar Pei
*French bulldog
Breeds predisposed to juvenile onset demodicosis
*English bull dog
*Pit bull
*Sealyham terrier
Which DLA haplotypes (encode for MHC) are associated with generalized demodicosis in mastiffs and boxers?
FH2002
FH2975
FH2054
Is Demodex cornei it’s own species?
No. It is a short version of D canis (or dying ones!)
Are D injai females or males longer?
Males are longer than females
T or F: there is a third, unnamed species of demodex mites in cats (other than D gatoi, D felis)
True.
It has a longer gnathosoma and short opisthosoma than D cati.
Where in the USA is Demodex gatoi common
Southeast USA
Very regional
T or F: Short D canis (aka Demodex cornei) is more pruritic than D canis
True
Also, pruritic if 2’ bacterial infection
Clinical lesions of Demodex injai
Marked greasiness of dorsal trunk
Where in the skin does Demodex gatoi live
Stratum corneum (like sarcoptes)
NOT hair follicle
How to perform a trichogram for demodex
Pluck hairs from 1 cm^2 (50-100 hairs) in direction of growth. Put on mineral oil w/cover slip.
In intact female dogs, what can trigger recurrences of demodicosis
Estrus
T or F: systemic antibiotics should only be used for SEVERE bacterial pyoderma 2’ to demodicosis
True! Topical benzoyl peroxide shampoo was enough to clear mild/moderate cases, as long as ivermectin was administered for demodex
MOA of amitraz leave-on rinse
Monoamine oxidase inhibitor
Alpha 2-adrenergic agonist
Inhibits prostaglandin synthesis
AE of topical metaflumizone+ amitraz; topical fipronil + amitraz spot on products
Pemphigus foliaceus-like drug eruption
How to perform amitraz leave-on rinse
-Clip hair short
-Apply with sponge; allow to dry without rinsing
-Do not get wet BETWEEN weekly baths, so amitraz stays on the skin
-Do not ingest
AEs of Amitraz
*Depression, sleepiness
*Ataxia
*Pruritus, urticaria, edema
*Skin irritation
*Polydipsia, polyphagia
*Hypotension, bradycardia, hyperglucemia
*Vomiting, diarrhea
Reversal to amitraz toxicity
Yohimbine, atipamezole
Which humans need to avoid contact with amitraz
Diabetic humans
Which dogs are predisposed to amitraz toxicity
Small breeds: Pomeranians, Chihuahuas
CHIHUAHUAS ARE ON THE LABEL
Which medications should be avoided with amitraz
Other sedating agents (bc Amitraz is alpha-2 agonist)
Synergistic toxicity
What percent of dogs with amitraz monotherapy for their demodicosis do not achieve cytologic cure
20% – combo with other meds
T or F: Ivermectin is labeled for treatment of demodicosis in dogs but not cats
False. Only approved treatment for demodicosis in dogs is Amitraz
What is the most effective route to administer ivermectin (for tx demodex)
PO daily
> > > SC q1w, pour on 3x/w
AEs of ivermectin
Neurotoxicity!!
Early:
Mydriasis, temporary blindness
Lethargy
Vomiting
Ataxia, tremors
Late: Seizures, coma, respiratory failure, death
What is the first clinical sign of ivermectin toxicity
Mydriasis
Mydriasis is also the last sign to resolve of ivermectin toxicity
What is the antidote for ivermectin toxicity
None
Charcoal, IV lipids
(Flumazenil in rats, Physostigmine helps CNS short term but AEs)
Which breeds are sensitive to ivermectin? Mutation?
Collies
Australian shepherd dogs
Shetland sheepdogs
English sheepdogs
ABCB1 gene (formerly mdr1); autosomal recessive–> nonfunctional P-glucoprotein = ATP-dependent transmembrane transporter protein, esp at the blood-brain barrier. Cannot transport drugs OUT of the CNS
What medications should be avoided with ivermectin
Other substrates of P-glycoprotein efflux transporter
ALSO Spinosad products —> inhibitor of P-gp!
Which medication is safer than ivermectin in ABCA1 dogs (though still titrate dose up!
Moxidectin
What is the best tolerated method of moxidectin/imidacloprid administration
Topical q1w
Isoxazoline MOA
Bind to ligand-gated chloride channels (GABA receptors). Block Cl ions across cell membrane of pre and postsynaptic cleft.
=
Prolonged hyperexcitation –> death
How is fluralaner excreted
Unchanged in feces by hepatic elimination
How is afloxolaner excreted
Biliary excretion of unchanged afoxolaner
Biliary and renal clearance of afoxalaner metabolites
At what age can afoxolaner, surolaner be administered to puppies?
8 weeks
T or F: inactivated Parapox virus suis subcutaneously with amitraz leave on may be benefitical. Immunostimulant
True
Which oral isoxazoline has been successful in treating a CAT with demodicosis
Fluralaner
