Sarcoptic Mange

Transmission

Puppy with sarcoptic mange
Caroldermoid 2006, Wikimedia Commons

• Close contact

• Adults and larvae can be transferred from one skin surface to another

Pathogenesis

• Erythema with papule formation

• Scale and crust formation
  • Alopecia

• Intense pruritus for 1 week
  • Self-inflicted trauma
  • Scab formation

• Wrinkling and thickening of skin

• Hypersensitivity may develop
  • Rash develops

Sarcoptes scabiei

• Causes scabies

• Strains of S. scabiei can be passed between different animals and cause clinical signs although the infection is likely to resolve spontaneously and be unlikely to establish

Diagnosis

• Skin scraping until capillary blood appears
  • Adults, eggs, immature mites and faecal pellets can be seen microscopically

• Place material on a microscope slide

• Add 10% KOH

• Warm slide over bunsen flame

Treatment

• Acaricide
  • For more information on acaricides click here

• Treat both infected and in-contact animals

• Older products have to be given in repeat treatments

• Avermectins are effective in farm animals

• Selamectin is available as a good spot-on for dogs

Dog

• Sarcoptic Mange is highly contagious
• Intense pruritus
• First signs appear at edges of ears, then progresses to muzzle, face and elbows

Cat

• Is rare

Pig

• Sarcoptic Mange is an important condition, 35% pigs are asymptomatic carriers

• First signs of infestation appear on the ears before spreading to the rest of the body

• Transmission from sow to piglets whilst suckling and from boars to gilts at service

• Infestation adversely affects productivity
• Control for pigs:
  • Treat sows before entering the farrowing pen
  • Treat boars at 6 month intervals

Cattle

• Sarcoptic Mange is most frequently seen in housed cattle

• Notifiable in USA and Canada

• Often called 'neck and tail mange' as lesions most often seen on neck and tail

• Infestation adversely affects productivity

Sheep

• Sarcoptic Mange is Notifiable in UK

• Lesions on hairy parts of face
  • E.g. Face, ears, axillae and groin

• Causes considerable hide damage in local African breeds of long haired sheep

Horse

• Sarcoptic Mange is Notifiable in UK

• Lesions begin on head, neck and shoulders then spread to rest of body

Other

• Caused by Sarcoptes scabiei
• Highly contagious
• Mainly in pigs, dogs, also horses, cattle, sheep, goats and cats
• Intense pruritus due hypersensitivity to mites borrowing through stratum corneum
• Usually starts with external pinnae -> head -> neck -> generalised
• Grossly:
  • Erythematous macules, papules, crusts
  • If chronic -> lichenified, hairless
• Microscopically:
  • Hyperplastic, spongiotic, superficial perivascular dermatitis
  • Crusting, eosinophil infiltration
  • Mites are not commonly seen, but eggs and feces may be found in stratumn corneum

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