7. Ectoparasites: Sarcoptes, Notoedres, Cheyletiella, and Lice

If you asked 100 small animal veterinarians, which mite or

insect is the most clinically relevant in this lecture, the answer would be?

sarcoptes

T/F Sarcoptes sp. is species specific

True

What is the sarcoptes species that are seen in dog, fox (reservoir),

coyote?

S. scabiei var. canis

What is the Sarcoptes spp that is seen in the cat?

Notoedres sp.

What is the Sarcoptes spp that is seen in the pig?

S. scabiei var. suis

What is the Sarcoptes spp that is seen in the cow?

S. scabiei var. bovis

What is the Sarcoptes spp that is seen in the humans?

S. hominis

How does sarcoptes infect their host?

Transiently

T/F Sarcoptes is considered zoonotic

True

When do sarcoptes die?

7-21 days

What are the clinical signs of Sarcoptes that are characteristic?

Pruritic papular rash - arms, neck, belt- line

Life cycle of sarcoptes go!

• Female burrows into the skin, forms a tunnel

• Mites do not live very long off the host

T/F Highly contagious and transmitted by intimate contact with skin

True

What is the HALLMARK sign of Sarcoptes sp?

Intense pruritus within 21-30 days

T/F Variable pruritus within multi-dog household it can be asymptomatic ->intense pruritus

True

How many mites does it take to cause intense pruritus in dog?

few (

What type of hypersensitivity response does sarcoptes cause?

Type 4 (delayed)

What are the clinical signs of Sarcoptes sp?

• Extreme pruritus - 10/10

• Papular dermatitis

• Erythema

• Excoriations

• Secondary pyoderma (folliculitis)

• Lichenification, hyperpigmentation -chronicity

What is the KEY distribution of sarcoptes? (4)

• Lateral pinna margin

• Lateral hocks and elbows

• Ventrum

• Generalized

(less haired areas)

What is the MAIN diagnostic test for sarcoptes?

Superficial skin scraping

What do sarcoptes look like under the microscope?

LONG, unsegmented pedicels on pretarsi with terminal suckers;

adult 200-400 microns

T/F It is very easy to find the sarcoptes mites

Fasle, HARD to find them

Does a negative skin scrape rule out sarcoptes?

NO Negative skin scrapes do NOT rule out!!!

What is one of the best way to diagnose sarcoptes sp?

Response to treatment

What are THREE other things you can do to diagnose Sarcoptes?

• Fecal evaluation

• Biopsy with histopathology

• ELISA

What side effect can ivermectin cause and it is the reason you have to titrate up?

neurotoxicity

What are the breeds you should NOT treat with ivermectin due to neurotoxicity?

Collie, Sheltie, Border Collie, Aussie, OESD, Sighthounds (white feet dont treat)

What drug is contraindication with ivermectin? ( an old timey flea and tick in the 2000s)

Spinosad

How do you treat neurotoxicity due to ivermectin?

IV lipid

What are the THREE drugs that are safe for treating sarcoptes?

Selamectin, Moxidectin, Milbemycin

What is the NEW treatment for sarcoptes?

Isoxazolines

What are some of the examples of Isoxazolines that can be used to treat Sarcoptes?

• BravectoTM - fluralaner

• Nexgard® - afoxolaner

• Simparica® - sarolaner

• Credelio® - lotilaner

What is the prognosis for treating Sarcoptes sp?

• Good with appropriate treatment

• Advise owners to seek medical treatment if

symptomatic

What is the name of the mite that causes "cat scabies" and head mange?

Notoedres sp

T/F Notoedres sp is contagious through indirect and direct contact

True

What is the MAIN pathogenesis of Notoedres sp?

Highly pruritic

What is the mite count of Notoedres sp that causes highly pruritic?

HIGH

What are the FOUR animals/patients that can get a transient infection from Notoedres sp?

fox, dog, rabbit, humans

What are the clinical signs of Notoedres sp? Chronic or Early lesions?

• Severe pruritus

• Early lesion - erythematous papule

• Chronic lesions - lichenification, thick yellow

crusts, excoriations

What is the lesion distribution of Notoedres sp.? (3)

He said this was the most important slide

• Head - ear pinna, face, periocular, neck

• Feet

• Perineum

(note: he said that feet and Perineum help him point that it is Notoedres rather than skin allergy)

How do you diagnose Notoedres sp?

• Clinical signs

• Superficial skin scrape

What can you give to help treat the pruritus caused from ectoparasites?

Steroids

How do you topically treat Notoedres sp?

• Clip hair and bathe keratolytic

shampoo

• Lime sulfur dip (Weekly x 6-8 wks)

What topical treatment is like superrrrr toxic to the kitty cat?

Permethrin

What are some of the systemic treatment for Notoedres?

• Selamectin/Sarolaner - q2 wks x 3

tx

• Moxidectin- q2 wks x 3 tx

• Ivermectin

T/F Ivermectin has increased toxicity in cats

True

What drug class should you give to treat notorides?

Isoxazolines

What is known as the walking dandruff?

Cheyletiella sp

What is the lifecycles of Cheyletiella sp?

• 21-day lifecycle

• Obligate parasites

How would you describe Cheyletiella sp.?

- Nonburrowing surface feeders

-HUGE mouthparts

What are the clinical signs of Cheyletiella sp?

• Pruritus

• Severe dorsal scale - moves!

• Papules

• Exfoliative erythema

• Miliary dermatitis and "fur mowing"

What is the lesion distribution of Cheyletiella sp?

• Dorsum

• Face - muzzle, eyes, dorsal head

How do you diagnose Cheyletiella sp.?

• Moving dorsal scale - magnification lens

• Nits in hair coat

• Superficial skin scrape

• Acetate tape prep

• Fecal exam

• Flea comb

What is the MAIN treatment for Cheyletiella sp?

Isoxazolines

What are some other treatments for Cheyletiella sp?

• Keratolytic shampoo

• Lime sulfur

• Ivermectin

What should you treat the environment with in regards to Cheyletiella sp?

pyrethrin/permethrin

T/F Cheyletiella sp is zoonotic and prognosis is good

True

How would you describe lice?

• Flat, wingless, elongated insect

• Highly host-specific

T/F There are TWO types of lice- sucking and chewing

True

What is the clinical signs of lice?

• Nits on hair

• Adult lice close to skin

• Pruritus

• Scale

• Crust

• Excoriation

• Papules

What is the lesion distribution with lice?

• Ears

• Neck

• Shoulder

• Anus

• Extremities

How do you diagnose lice?

• Visualization of lice or nits in

hair coat

• Handheld magnification

• Microscopic magnification

• Flea comb

• Acetate tape prep

• Trichogram

How do you treat lice?

• Any flea treatment

• Lime sulfur

• Pyrethrin spray

• Ivermectin

What is the prognosis of Lice?

Excellent

What is seen in the in the dog and Bartonella henselae?

Acanthocheilonema reconditum