[2] It causes small pustules in the skin of primarily sheep and goats, but can also occur on the hands of humans.

[4] However, it is sometimes required to excise the pustules..[4] The vaccine used in sheep to prevent orf is live and has been known to cause disease in humans.

Consequently, it is important to observe good personal hygiene and to wear gloves when treating infected animals.

[7] It has been recorded since the late 19th century and has been reported from most sheep-or goat-raising areas, including those in Europe, the Middle East, the United States, Africa, Asia, South America, Canada, New Zealand and Australia.

Symptoms include papules and pustules on the lips and muzzle, and less commonly in the mouth of young lambs and on the eyelids, feet, and teats of ewes.

Orf in the mouths of lambs may prevent suckling and cause weight loss, and can infect the udder of the mother ewe, thus potentially leading to mastitis.

[1] A live virus vaccine (ATCvet code: QI04AD01 (WHO)) is made from scab material and usually given to ewes at the age of two months, but only to lambs when there is an outbreak.

In rare cases, mostly involving young lambs, lesions are found on the tongue, gums, roof of the mouth and the esophagus.

In one case it was shown that a severe form of orf virus caused an outbreak involving the gastrointestinal tract, lungs, heart, as well as the buccal cavity, cheeks, tongue and lips.