Knemidocoptiasis

Introduction

Knemidocoptes is a small, round burrowing mite found in birds. It has short legs and a U- shaped chitinous bar found behind the head. It' lifecycle is very similar to Sarcoptes.

Knemidocoptes is the only genus of burrowing mite found in birds. There are three main species of Knemidocoptes that affect birds and these are K. mutans, K. gallinae and K. pilae, which all cause different disease manifestations and clinical signs.

Clinical Signs

Signs are dependent on which mite is present:

K. gallinae

The disease associated with this mite is called depluming itch. Mites burrow into the feather shafts and cause intense pruritus and pain, so much so that the bird will pull out its feathers. Therefore clinical signs include loss of feathers by self trauma, depression, intense pre-occupation in pulling out feathers. The bird will often not eat and will appear to lose weight.

K. mutans

The disease caused by this mite is called scaly leg. This specie of mite burrows beneath leg scales and causes them to loosen and rise. Clinical signs will include the bird having distorted legs and claws and may appear lame. The bird may also be paying particular attention to their legs and may show signs of pruritus.

K. pilae

The disease associated with this mite is called scaly beak and is caused when the mites burrow into feathered parts of the beak and into the lightly feathered areas of the face and body. Clinical signs will include loss of feathers and scaliness around the base of the beak and spreading over the face. There may be mild pruritus but not as severe as other forms in the genus.

Diagnosis

History and clinical signs are very suggestive of the disease. A deep skin scraping is required to identify the mites and this should be performed by scraping the skin until capillary blood is seen.

Treatment and Control

There are few licensed acaracidal treatments for poultry. Repeated treatment with one of the licensed treatments is necessary to cure this disease. Prophylactic acaracidal treatment can be used for prevention.

References

Jordan, F, Pattison, M, Alexander, D, Faragher, T, (1999) Poultry Disease (Fifth edition), W.B. Saunders

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition), Merial

Randell, C.J, (1985) Disease of the Domestic Fowl and Turkey, Wolfe Medical Publication Ltd

Saif, Y.M, (2008) Disease of Poultry (Twelfth edition) Blackwell Publishing