Orf

ORF

Orf is an old Saxon term for a human infection caused by a parapoxvirus of sheep andgoats. Synonyms for the infection in animals include contagious pustular dermatitis, ec-thyma contagiosum, pustular ecthyma, and “scabby mouth.” Humans usually acquire the infection by close contact with infected animals and accidental inoculation through cuts or abrasions on the hand or wrist. The typical skin lesion is solitary; it begins as a vesicle and then evolves into a nodular mass that later develops central necrosis. Regional lym-phadenopathy sometimes develops. Dissemination is rare. The average duration of the le-sion is 35 days, followed by complete resolution. The diagnosis is usually made on the basis of clinical appearance and occupational history. Serologic confirmation or electron microscopy of the lesion can be performed but is rarely necessary.