Equine dermatophilosis

Definition

•It is self limiting disease of equine caused by dermatophilus conglensis, characterized by moist exudative dermatitis and lesion appear as tufts of matted hair and crust over the shoulder and back

Etiology

•Dermatophilus conglensis live in crust or scab from infected animal for 42 m

•Predisposing factors:▫Change in atmospheric temperature and

humidity or prolonged skin wetness▫Trauma and concurrent disease▫Biting insect

Epidemiology•Distribution: It is worldwide distributed and

reported in Egypt.•Animal susceptibility: horse, donkeys and

mules•Mode of infection

▫Source of infection; crust or scabs from infected animals

▫Mode of transmission; invasion of organism through cutaneous wound or abrasion, through contact with infected animal and spread mechanically by stable fly (stomoxys) and house fly (musca domestica)

Pathogenesis

•Following infection, under normal condition, the stratum cornium is an effective barrier against infection, but when the resistance of skin was lowered, the organism penetrate deeply and invade living dermis inducing an acute inflammation or exudative dermatitis

Clinical signs•In long haired horses;

▫There are large plaques of matted hairs and crusts which cover a moist gray to pink indurated surface

•In short haired horses;▫There are multifocal nodules covered with

crusts or scales in size of 1 to 2.5 mm ▫The lesion present on muzzle, around eye,

distal extremities and along the back•In racing horses;

▫Lesion may present at pastern or fetlock as numerous scabs adherent to base of hair follicles with excessive exudation fissures and cracks resulting in lamness.

Diagnosis

•Direct impression smear for isolation and identification of the organism

•Isolation of the organism on blood agar, showed small brown hemolytic colony having rough texture

Treatment

•Clipping the hair of infected area and remove the crust

•Local application of .25% chloramephnicol for 5-7 days

•Systemic antibiotic in generalized cases as pencillin streptomycin for 3-5 days

•Bandage over pastern and fetlock with application of creams for neomycin sulfate and hydrocortisone