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