Sarcoptes scabiei (1)

Question 1

What are the common names?

Answer 1

Sarcoptic mange mite

Itch mite

Scabies mite

Cattle: Neck and Tail mange

Question 2

What are the hosts?

Answer 2

Dogs

Pigs

Cattle

Humans

Each host has its own strain

Largely host specific

Question 3

Describe adults

Answer 3

Up to 400 micro m

Many spines on body

Round

Legs short

Suckers on long, unsegmented stalks differ between sexes

Pretarsi or pedicels are long and unsegmented

Question 4

Explain the life cycle

Answer 4

Main mode of transmission

 - Carrier sows to piglets during suckling
 - During service between infested boars to gilts
 - Piglets: signs appear within 3 weeks of birth

Females burrow in skin

Lay eggs in burrow

Larvae hatch, return to surface of skin

All stages tunnel in epidermis, resurface, burrow again

Transmission: by direct contact

 - Infestation by indirect contact through fomites, less frequent
 - Pigs: transmission from mother to offspring during nursing

PPP: 2-3 weeks

Question 5

What are the predilection sites?

Answer 5

Varies for host

Epidermal layers if skin, generally less haired areas

Question 6

What are the predilection sites in dogs?

Answer 6

Earwax

Elbows

Ventral thorax

Abdomen

Most zoonotic concern

Question 7

What are the predilection sites in pigs?

Answer 7

Head

Inner surface of ears

Question 8

What are the predilection sites in cattle?

Answer 8

Neck

Base of tail

REPORTABLE

Question 9

Describe the clinical signs

Answer 9

Scratching

Rubbing

Chewing

Self-excoriation

Erythema

Alopecia

Oozing of blood and serum - forms crust, eventually scabs

Thickened skin

Begins on hairless areas of body

Lateral elbow

Pinna of ear

Lesions of follicular papules, areas of erythema, crusts of dried serum and blood and pruritis

Thickened ear edge of sarcoptic mange

Lose condition

First lesions are wheals; general erythema around eyes, snout, external ears, front of hocks

Skin becomes wrinkled, covered with crusty lesions, thickened

Lesions progress to hyperkeratosis

Potentially most severe cattle mange

Mild infection - scaly skin

Severe infection - thickened skin

Downgrading of hides

Drop in meat and milk production

Question 10

Describe the Pathogenesis

Answer 10

Tunneling activity along with secretions -> Hypersensitivity

 - Pruritis - sudden and intense
 - Dermatitis
 - Epidermal Hyperplasia

Pigs
- Hypersensitivity phase followed by desensitization/no
hypersensitivity and development of a carrier state
- May also occur in dogs

Question 11

How do you diagnose?

Answer 11

Skin scraping - margin of lesions
- Several often required

Pigs - mites are more reliably found in earwax

Pruritis is frequently a better indicator of infestation than mite recovery, especially in sows and nursing piglets

Question 12

How do you treat and prevent?

Answer 12

MCLs effective

Dogs - treatment based on clinical signs

Cattle - treatment carried out under supervision

Sows - treatment prior to farrowing as prevention method
- Swine facility eradication protocols

Treatment of pets cure the humans they infest

Eprinomectin approved for lactating dairy cattle - Must be reported to
authorities

Question 13

What is important about Sarcoptes scabiei?

Answer 13

It is ZOONOTIC!