The Orf virus - sometimes misdiagnosed as a more serious disease such as anthrax - is most commonly transmitted to humans on farms. It has also been reported in children who visited petting zoos and livestock fairs, the Centers for Disease Control and Prevention said.

But the CDC said people could also contract Orf by preparing infected sheep or goat meat for household use or when slaughtering the animals, and detailed four such cases in the report.

"In ethnically diverse communities, health-care providers might be unaware of patients having this type of animal contact and of the seasonal increases in contact associated with religious events," the report said.

"The popularity of hobby farming and home butchering also increases opportunities for household Orf exposures."

The report said that in 2010, a 42-year old man in Massachusetts assisted in a lamb sacrifice for the Muslim feast holiday Eid al-Adha, holding the animal's head with his left hand. Five days later, a small lesion appeared on one of the fingers of his left hand.

In another case, a 35-year-old man of Ethiopian descent cut his left thumb with a knife while slaughtering a lamb as part of Easter festivities and later suffered a thumb lesion.

Orf lesions often heal within a few weeks, CDC veterinarian Danielle Tack told Reuters. Doctors, particularly in urban areas, can sometimes misdiagnose Orf, she said.

(Editing By Cynthia Johnston and Eric Walsh)

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