Ovine and Caprine Contagious Ecthyma – NAVLE Study Guide
Overview and Clinical Importance
Contagious ecthyma (also known as orf, sore mouth, scabby mouth, or contagious pustular dermatitis) is a highly contagious, zoonotic viral skin disease caused by the Orf virus (ORFV), a member of the genus Parapoxvirus in the family Poxviridae. This disease has worldwide distribution and primarily affects sheep and goats, with goats typically experiencing more severe disease than sheep. It is one of the most common skin diseases in small ruminants and represents an important topic on the NAVLE due to its zoonotic potential and need for differentiation from foreign animal diseases.
The disease is characterized by proliferative skin lesions at mucocutaneous junctions, most commonly affecting the lips and muzzle. While typically self-limiting with low mortality in uncomplicated cases, secondary bacterial infections can significantly increase morbidity and mortality, especially in young lambs and kids.
Etiology
Causative Agent
The causative agent is the Orf virus (ORFV), which is the prototype species of the genus Parapoxvirus. Key characteristics include:
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