Orf (disease)

Orf ( ecthyma contagiosum, Contagious Pustular Dermatitis, Lip Grind the small ruminants, foot and Fußgrind ) is a skin disease and general infection of sheep, goats, chamois, reindeer and musk oxen and by the Orf virus ( Parapoxvirus ovis ), the genus Parapoxvirus ( PPV) belongs to the family Poxviridae, causes.

General

The disease has a cyclical pattern. In addition to the general infection, local and latent infections occur.

Epidemiology

Orf is spread worldwide and highly contagious. Transmission occurs through contact, through the air, and over fallen crusts and scabs. Also on skins, wool and meat, the infection can take place. Lambs are infected at birth or later. The morbidity is very high, the mortality only at 1%, albeit in lambs partly 20 - 50 %. Virus reservoir are latently infected older animals. Humans and monkeys are susceptible. People who are in close contact with ruminants are infected. However, the virus causes only minor skin rashes in humans.

Pathogenesis, pathology

The virus is absorbed through mucous membranes and small skin lesions. Then a local virus replication and subsequent washout occurs in the blood and lymphatic vessels in the lymphatic system and the liver, where the virus multiplies. Then usually there is a further washout and the viruses attach themselves to the typical locations of the skin. This cycle can be interrupted at any time.

Clinic

The incubation period is 3-8 days.

The labial form (" lip Grind ", " mouth Grind" ) is in the form pea-sized vesicles and pustules on the lips, which can extend to the nose, eyelids and ears. By drying it comes to the dark scabs that heal after 3 weeks.

The podale form (" Fußgrind " ) manifested by pustules at the coronet and between the claws, which are very painful.

The genital form shows up in pustules on udder (some with mastitis ), inner thighs, labia and foreskin.

The malignant ( malignant) form is characterized by an excitation propagation in the internal organs and manifests itself in fever, fatigue, swollen lymph nodes, lung inflammation and edema. The recovery extends over weeks. Especially lambs can starve because growths in the mouth, throat, esophagus and stomach lead to a loss of appetite.

Immunology

Convalescent animals are immune. The immunity is depending on the severity but not stable.

Diagnosis

Electron microscopic detection of viruses in the crusts. Also ELISA possible. Longer the cultivation in culture. After 3 weeks, PPV -antibody detection is possible.

Combat

The control can be effected by vaccination with a live vaccine. Also lambs need to be vaccinated, as the mother animal vaccination is not sufficient.

Legal provisions

Orf is one of the zoonoses. It is a notifiable animal disease.