What are the other Names for this Condition? (Also known as/Synonyms)

• Ecthyma Contagiosum
• Infectious Labial Dermatitis
• Orf

What is Orf Disease? (Definition/Background Information)

• Orf Disease is an infection caused by the parapoxvirus, Orfviridae. It is a zoonotic disease - one that is transmitted from animals to humans. The virus is primarily found in animals, such as sheep and goats, but it may be transmitted to humans via close contact, usually through open wounds
• The disease results in the formation of tender skin lesions, commonly on the fingers and hands. This may be rarely accompanied by low-grade fever and swollen lymph nodes. Orf Disease is generally not a severe illness and the affected individuals usually get better within about 6 weeks, with adequate treatment (such as topical applications)

Who gets Orf Disease? (Age and Sex Distribution)

• Any individual (child or adult) is susceptible to Orf Disease; it is caused by an exposure to infected sheep, lambs, or goats
• Both males and females are affected and there is no gender bias observed
• Worldwide, all racial and ethnic groups are at risk

What are the Risk Factors for Orf Disease? (Predisposing Factors)

Contact with infected animals, specifically goats, sheep, and lambs, increases one’s risk for Orf Disease. The risk factors may include:

• Contact with sheep, lambs, and goats, especially young ones, such as rearing these animals
• Children or adults using feeding bottles to nurse young sheep/lambs/goats
• Cleaning animal sheds
• Sheep shearing
• Meat handling and storage
• Working in slaughterhouses
• Cleaning dead animals and disposing carcasses of infected animals
• Veterinarians who handle the sick and infected animals
• Children playing with young animals on farms and grazing lands
• Handling raw meat while cooking
• Having open wounds and cuts on the body

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Orf Disease? (Etiology)

Orf Disease is an infection that is caused by the parapoxvirus (PPV), Orfviridae, a DNA virus. In many cases, the virus is accidentally transmitted from infected animals, such as sheep and goats, to humans through direct contact. In animals, the virus is a common pathogen that can cause a highly contagious infection.

The method of transmission from infected sheep and goats to humans may take place via:

• Cuts and wounds in the skin coming in direct contact with infected animal fluids - this is the primary route of infection in humans
• Direct contact with the infected animals; through the mucous membranes
• Inadvertent animal bites
• Handling or holding raw meat of infected animals
• Using/sharing materials (used for infected animals) that are infected

Following infection, an incubation period of 3-6 days is noted prior to onset of signs and symptoms. However, the condition is not known to spread from one individual to another.

What are the Signs and Symptoms of Orf Disease?

The signs and symptoms of Orf Disease may vary from one individual to another, and it may be mild or severe. These may include:

• Presence of well-defined and firm skin lesions that appear as red papules
• The papules then form blisters with blood and pus
• The blisters break and ooze pus to then form a firm crusted lesion. Following this, they heal with minimal to no scarring
• The lesions are usually tender and sometimes painful, particularly in the initial stages
• Many individuals present a solitary lesion, but multiple lesions are not uncommon
• Any part of the body may present the lesion, although common sites are the fingers, hands, and arms. Sometimes, the face, eye, or even the penis may be affected 
• The size of most lesions are between 2 to 3 cm, but some may be as large as 5 cm
• As the blister heals, it can temporarily leave a rough pebble-like appearance before transitioning to normal. At this stage, no treatment is generally needed

Sometimes, mild fever and enlarged lymph nodes (on the arms) may be noted.

How is Orf Disease Diagnosed?

An Orf Disease is diagnosed through the following tools:

• Complete physical examination with evaluation of medical history and occupational history (including contact with animals such as sheep, lambs, and goats)
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Complete blood count (CBC) and antibody tests
• Polymerase chain reaction (PCR) assay
• Tissue culture: A culture may be performed to confirm the presence of virus and to rule-out other causes of infection. In this culture, a small amount of pus or fluid from one of the sores is collected and sent to the lab for testing. The test results can help confirm the presence and type of virus (if any)
• Skin biopsy, if necessary: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

A differential diagnosis to eliminate other conditions may be considered, before arriving at a definitive diagnosis. These may include:

• Milker’s nodule
• Cutaneous anthrax

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Orf Disease?

There are usually no complications that arise from Orf Disease.

• In some individuals, it may give rise to cosmetic concerns and stress
• Scratching or itching of the lesions may lead to bleeding and ulceration. This can cause secondary bacterial or fungal infections to develop
• Eye infections can be severe and may even cause vision loss
• Recurrence of infection; although, recurrences are known to be milder than the initial infection
• Individuals with poor immune systems may have a progressive condition that does not spontaneously resolve
• In some cases, the presence of parapoxvirus may lead to other skin conditions such as erythema multiforme and pemphigoid

How is Orf Disease Treated?

In a majority of cases, no treatment is required for Orf Disease since it is a self-limited infection. In some cases, the healthcare provider may recommend the following measures:

• Symptomatic treatment
• Application of topical creams and ointments, if needed; the wounds have to be kept covered to avoid contamination
• Removal of large skin lesions using surgery (shave excision)
• Use antibiotics in case of superimposed bacterial infections

How can Orf Disease be Prevented?

The following preventive measures may be adopted to avoid contracting Orf Disease:

• Handwashing with soap and water before handling food/meat or eating
• Cooking meat thoroughly
• Cleaning all utensils and food preparation surfaces with soap and water
• Maintain personal and body hygiene
• Wearing gloves while handling sick or dead animals, especially to be practiced by veterinarians, farmers/farm hands, and slaughterhouse workers
• Adhering to safety precautions in high-risk work places that deal with animals
• Handling animal specimens under appropriate bio-safety conditions (since lab workers could be at risk)
• In slaughterhouses, separating the slaughtering place from the processing area, can help avoid spread of the virus
• Taking steps to rear healthy farm animals, such as by vaccinating the herd and cleaning sheds regularly
• Quarantining infected herds and eliminating them from the healthy stock of animals

Individuals with compromised immunity are strongly recommended to avoid handling farm animals or hold similar occupations.

What is the Prognosis of Orf Disease? (Outcomes/Resolutions)

The prognosis of Orf Disease is usually good since it is a self-limiting infection that resolves spontaneously within about 6 weeks.

Additional and Relevant Useful Information for Orf Disease:

• Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition
• The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse