Entom: Chapter 11: Astigmata

Sarcoptidae

burrowing mite in the skin, feathers, and hairs of the host

Sarcoptidae

globose or round body and striae of skin are interrupted by scales and spinose areas

Sarcoptidae

coxae are sunk into the body "short-legged", the 3rd and 4" pair do not propel from the margin of the body

Anus

terminal which is ventral or dorsal in position

Cutting/Sucking

The chelicerae of sarcoptidae are adapted for

Clinical signs of scabies in dogs

• Loss of hair

• Thickened, wrinkled skin covered with crusts

• Formation of papules in young lesion, which later form vesicles and exudates

• Rupture of papules with encrustation of lymph

Clinical signs of scabies in Pigs

• Generalized focal erythema

• Pruritus and later encrustation on the ears and skin on the back region which may become very thick then crack after leaving deep wounds which becomes invaded by secondary bacterial infection

Clinical signs of scabies in horses

• Papule formation and pruritus

• Formation of crusts and scabs which is associated with loss of hair

  • Emaciation and cachexia

Clinical signs of scabies in Cattle and Carabao

• Rubbing against suitable objects

• Pruritus and bald patches on head and neck with marked thickening of the skin

Clinical signs of scabies in Sheep

• Sarcoptic mange is a prevalent condition in sheep, especially in wool-producing breeds.

• Lesions typically appear on areas without wool, such as the head and legs, starting as erythematous and scurfy.

• Affected sheep experience intense pruritus, leading to continuous scratching and rubbing, hindering their ability to graze, which results in progressive emaciation.

• Thick crusts form on the affected areas.

• In haired sheep, the condition can affect the entire body.

Clinical signs of scabies in Goats

• Sarcoptic mange in goats is a chronic issue, often misidentified as "skin disease" for extended periods prior to diagnosis.

• Lesions in goats also involve irritation, crusting, hair loss, and excoriation due to rubbing and scratching.

  • In chronic cases, the skin becomes thickened, and nodules may develop on less well-haired skin areas, such as the muzzle, around the eyes, and inside the ears.

Notoedres

Dorsal striations of the idiosoma are in concentric rings (thumb-print like) no scales or spines are present

Notoedres

Highly contagious; largely affecting domestic cats land causes ear mange

Notoedres

lesions occur chiefly on the ears and back of neck but may extend to the face, foot, and hind paw or even the whole body in kittens

Notoedres

burrowing activity of females damages keratinocytes, leading to cytokine release and to cutaneous inflammation; the skin becomes marked thickened and wrinkled tips of ears and skin over the face and neck develop crust and scale formation

Notoedres

affected animal may become severely debilitated and may be fatal in 4-6 months

Notoedres cati

ears, head, and back of the neck of cat

Notoedres cati variabilis cuniculi

ear of rabbit

Ntoedres muris

Rats

Knemidocoptidae

the only astigmatid mites found in poultry and birds

Knemidocoptidae

round body, short, stubby legs

Knemidocoptes gallincae

Depluming itch mite

Knemidocoptes gallinae

mites burrow deep into the skin alongside the shafts of the feathers and cause intense itching, inflammatory condition particularly on the back, head and neck, top of the wing, and around the vent

Knemidocoptes gallinae

birds pull out the feathers which break off readily

Knemidocoptes mutans

highly contagious mite; common in the Phils.

Knemidocoptes mutans

Scaly leg mite

Knemidocoptes mutans

• mites burrow beneath the scales into the skin of the foot and leg of poultry from the ground

  • females give birth to live larvae

Knemidocoptes mutans

inflammation with exudate that hardens on the surface and displaces the scales; this is accompanied by keratinization which renders the scales "powdery" in appearance

Knemidocoptes pilae

• occurs in caged birds like parakeets and lovebirds

• beaks become deformed, scaly, and crusty

Psoroptidae

oval-bodied, non-burrowing mite; parasitic in surface layers of skin causing the formation of a thick, heavy scab rather than a thickened skin

Psoroptidae

long legs, and pretarsi with long three-segmented pedicels

Psoroptes ovis

Serious and reportable form of mange (Scabies or sheep scab) in sheep, pruritic dermatosis in cattle, and horses

Psoroptes cuniculi

causes ear canker in rabbit