Orf Viral Infection

Excerpt

Orf viral infection, also known as contagious pustular dermatitis or ecthyma contagiosum, is a zoonotic and occupational infection acquired from infected sheep and goats. Orf is caused by the parapoxvirus Orfviridae. The orf virus plagues young sheep and goats, which are their natural host range. The virus induces vesicular, papular, and nodular lesions, prominently appearing in the lips and mouth of affected animals, where observers may perceive it as a mouth sore. In humans, however, it usually presents on the dorsal hands or fingers at areas of contact with the infected animals. Orfviridae is notorious for jumping hosts to human populations after close contact with a zoonotic source with active lesions or via fomites.

Orf passes through 6 clinical stages and is usually diagnosed with a clinical history of handling sheep, goats, or other associated animals during one of the 6 clinical stages in a classic area. Testing through a skin biopsy or a polymerase chain reaction test may be used to aid in the diagnosis of suspicious lesions for which there is no specific clinical history of vague clinical symptoms. Additional testing, such as cell culture or electron microscopy, may be needed when considering other causes of nodules on the hands (eg, Milker nodule, cutaneous anthrax). Histopathologically, Orfviridae appears similar to other viruses with eosinophilic intracytoplasmic inclusions and ballooning degeneration. Treatment may not be necessary for immunocompetent patients, as the disease usually resolves in 6 to 8 weeks. However, multiple treatments can be implemented to prevent the worsening of the disease in patients with immunosuppression.