Orf virus infection in humans--New York, Illinois, California, and Tennessee, 2004-2005.

Orf virus is a zoonotic parapoxvirus endemic to most countries in the world and is principally associated with small ruminants (e.g., sheep and goats). Human orf infections appear as ulcerative skin lesions after contact with an infected animal or contaminated fomite. This report summarizes the epidemiologic and laboratory investigations of four sporadic cases of human orf infection, emphasizing the temporal association between human lesions and skin trauma or recent flock vaccination with live orf vaccine. This zoonotic infection shares clinical manifestations and exposure risks with other, potentially life-threatening zoonoses (e.g., cutaneous anthrax) and is likely under-recognized because of a lack of clinical suspicion and widely available diagnostics. Barrier precautions and proper hand hygiene are recommended for the prevention of orf virus infection in humans.