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.

Case 1. On March 1, 2004, a woman aged 51 years from upstate New York noted an area of erythema approximately 4 mm in diameter on the middle finger of her right hand. During the next several days, the lesion evolved into a clear, solitary vesicle with surrounding erythema. On March 12, she visited her family physician, who prescribed penicillin and warm water soaks. The patient did not recall any trauma, including animal bites, although she regularly cared for goats on her family farm. She reported having bottle-fed a kid goat with a sore on its mouth approximately 1 week before the appearance of the lesion.

The patient did not improve and, on March 15, she went to a local hospital. The lesion on her finger had progressed to 2 cm in diameter with a 3--4 mm central white ring and umbilication. Her examination was otherwise unremarkable. At the hospital, the ulcer was debrided and a serous/gelatinous material was extracted. Routine bacterial cultures were negative. The patient was treated empirically with ciprofloxacin and amoxicillin-clavulanate.

On March 22, after discussion with local veterinarians, she contacted the New York State Department of Health to inquire about diagnostics for orf virus infection. Specimens collected on March 15 were forwarded to CDC and determined to be positive at both genus (Parapoxvirus) and species (orf virus) level by real-time polymerase chain reaction (PCR); standard PCR (i.e., visualization of amplicons by gel electrophoresis) (1) for genus and species was negative. By April 1, the lesion had spontaneously healed without scarring. No other family members or farm attendants reported similar skin lesions.

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Source: CDC MMWR Weekly
January 27, 2006

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