Etiology
It is caused by parapox virus. The disease is found all over the world.
Species affected
It affects domestic sheep and goats. Man is infected accidentally. It has been observed in dogs fed affected unskeamed carcasses.
Transmission
The disease is very contagious.
Clinical signs
The natural disease is proliferative and after a few days of incubation period, papules appear, enlarge and exude. This is followed by crust formation. The scabs are firmly adhered. The scabs fall of 3-5 weeks leaving white scar of new epithelium. There is no fever in this disease. The scabs are centrifugally distributed. In lambs and kids, the lesions cluster around the lips, muzzle and lower limbs. In sucking lambs, tooth eruption may favour development of oral lesions which spread to lips, muzzle. Lesions may also develop at castration and docking site. Outbreaks of induced balanoposthitis and vulvitis can also occur. Mastitis may occur when the teat are infected. The disease is rarely fatal but can cause significant loss in condition when the lesions make feeding very difficult.
Diagnosis
This is based on clinical signs, isolation and recognition of the virus.
It can be diagnosed using immunodiffusion test.
Differential diagnosis
Blue tongue
Labial streptotricosis
PPR
Rinderpest
Foot and mouth disease
Immunology
Animals that are recovered possess circulatory antiboby passed to the young in the colostrum. Majority of infected animals are able to resist the infection if re-exposed.
Prevention and control
Orf appears to be endemic in most flocks. Prevention is difficult. Live vaccines are commercially available. Antibody therapy, removal of scabs and application of antibiotic cream or iodine or antibiotic ointment is necessary.
Systemic antibiotic can be given to animals.
Post a Comment