Orf is a viral skin disease that can be spread to humans by handling infected sheep and goats.
The disease – caused by a parapoxvirus – is also known as:
In humans, the first sign of orf is a small, red, itchy or painful lump (lesion) that usually appears on the fingers, hands, forearms or face after an incubation period of 3 to 5 days.
There may be more than 1 lesion in some cases.
The lesion will usually be firm, red or blue in colour, and 2 to 5cm in diameter.
As the condition progresses over a 3- to 6-week period, a pustule or blister that weeps fluid will develop on top and eventually crust over.
Other possible symptoms include a high temperature, general tiredness (fatigue) and enlarged lymph glands.
Orf is a zoonotic disease (zoonosis), which means it can pass between animals and humans.
It's not possible for humans to pass the virus on to each other.
The virus is spread by handling infected sheep or goats, infected carcasses, or contaminated material.
Handling infected animals near their mouth is thought to increase the risk of orf.
People who make direct close contact with infected animals are most at risk, including:
People with a weakened immune system (immunocompromised), open wounds or other skin diseases are more likely to be infected with orf and should take extra care around affected animals.
The best way to prevent the spread of orf is to follow good hygienic practices when handling or rearing sheep and goats.
This includes wearing protective gloves, good hand hygiene, and vaccinating animals at risk.
Orf is a self-limiting disease, which means it'll get better on its own without treatment. It usually clears up within 3 to 6 weeks.
It may be useful to cover the lesion with a sterile (hygienic) dressing and immobilise your finger to help reduce discomfort.
Read more about applying plasters and other dressings.
You should see your GP if the lesion is not healing, you develop a high temperature or you're in severe pain, as some people also develop a bacterial infection. This may require treatment with antibiotics.
In rare cases, the lesion may not go away and a minor surgical procedure may be required to remove it.
Although there's some evidence to suggest that using topical imiquimod cream may help to reduce lesions, you should speak to your GP or pharmacist for advice first.
Possible complications include: