Chorioptic Mange

Introduction

Chorioptes is a non- burrowing mite which resides on the skin surface

Hosts: Cattle, Sheep, Goats, Horses, Rabbits

Predilection sites: Skin- especially legs, feet (particularly heavily feathered horses), udder, abdomen and base of tail

Life cycle: Egg- Larvae- Nymph- Adult. This lifecycle takes around three weeks to complete. Eggs are found attached the the surface of the skin. Adults can survive off the ground for around three weeks, meaning transmission can be via bedding and housing as well as by direct contact.

All species are thought to be affected by the same strain of mite Chorioptes bovis

Pathogenesis

Chorioptes' mouthparts do not pierce the skin and they feed on skin debris and exudate, meaning is pathogenic significance is mild.

In cattle, economic significance is the main factor as infestation can cause damage to the hide by self trauma.

Clinical Signs

Cattle and Small Ruminants

Usually mild conditon
Rubbing and scratching of affected area
Hide damage
Usually affects the base of the tail, perineum and udder in cattle
Usually found on legs of sheep
In goats, affects lower hindlegs, hindquarters and abdomen

Horses

Induce crusty skin and lesions on the pastern, fetlock and cannon regions
Often seen in rough-legged horses with heavy feathering
Stamping, rubbing or biting of affected area<span id="fck_dom_range_temp_1298978581579_938" /><span id="fck_dom_range_temp_1298978581579_587" />
Occurs more commonly in colder months
Exudative proliferative dermatitis with secondary bacterial infection (greesy heels) can occur in severe cases
Thickened, hairless skin in more severe cases

Diagnosis

History and clinical signs
A skin scraping from the edge of a fresh lesion will often demonstrate the presence of the mite under a microscope

Treatment

There are no products currently licensed for treatment of Chorioptes. The list below contains a number of products that have been reported effective

Topical

Clip affected area
1% Selenium sulphide shampoo. Whole body shampoo
Fipronil (Frontline spray) on affected area

Systemic

Ivermectin, paste for horses, good to eliminate the mite in a group infestation
Treat all in-contact animals, disinfect housing and dispose of bedding.

References

Brown, C.M, Bertone, J.J. (2002) The 5-Minute Veterinary Consult- Equine', Lippincott, Williams & Wilkins
Fox, M and Jacobs, D. (2007) Parasitology Study Guide Part 1: Ecotparasites Royal Veterinary College

Lloyd, D.H, Littlewood, J.D, Craig, J.M, Thomsett, L.R. (2003) Practical Equine Dermatology, Blackwell Science
Taylor, M.A, Coop, R.L, Wall, R.L, (2007) Veterinary Parasitology third edition, Blackwell Science To_Do_-_Review