Also known as
Scabby mouth, sheep pox or ecthyma contagiosum
What is orf?
Orf is an infection caused by the parapox virus which primarily infects sheep and goats. The condition is most commonly seen in animal handlers, butchers and farm workers. Anyone can become infected by touching the affected animals or by contact with infected pastures. Orf occurs worldwide.
What causes orf?
Orf is spread through direct contact with lesions of infected animals or through fomites found in animal enclosures (touching contaminated surfaces or particles). Typically, infected animals have warty sores and scabs on their muzzle and, less commonly, on their lower legs and teats. However, some infected animals may not have any visible sores at all.
What does orf look like?
Orf lesions are usually seen on the fingers or hands of an individual who has touched the infected animal (e.g. bottle feeding or shearing the animal). Occasionally the orf lesions can also be seen on the face or other parts of the body that may have been in contact with the infected animal.
The orf lesion evolves through distinctive stages and can be painful. A red bump develops about 1 week after contact with the virus. An infected person may experience mild fever and malaise for the first few days. Red streaks (infected lymph channels) may be visible on the affected limb and the nearby lymph glands can be enlarged.
The red bump may grow from 2 to 5 cm and develop rings of white and red around a central red area, after which it usually becomes a blood/pus/fluid filled blister which can weep and bleed easily. A dry crust usually develops on top and the lesion then starts to take on a warty appearance. The lesion will heal without treatment after 4 to 6 weeks, usually without scarring. The infection does not usually spread from person to person.
How is orf treated?
There is no specific treatment as orf usually heals on its own. Appropriate dressing care and pain relief may be given if necessary. Antibiotics may be given if there is a secondary bacterial infection.
How can orf be prevented?
Those at risk should wear protective non-porous gloves when handling sheep and goats and practise good hand hygiene.
Further information about orf
This information has been written by Dr Yin Vun