Background

• Orf disease is also known as contagious ecthyma, is a viral skin infection that primarily affects sheep, goats, and occasionally other ruminants. The disease is caused by the Orf virus, a member of the Parapoxvirus genus. Orf is zoonotic, meaning it can be transmitted from animals to humans, particularly individuals who come into close contact with infected animals or their tissues. The virus is most encountered in regions with significant livestock farming or during periods of lambing and kidding. Orf can survive in the environment for extended periods and can enter the human body through broken skin, causing characteristic skin lesions.
• In humans, Orf typically manifests as localized, painful, and self-limiting papules or pustules that develop into crusted, scab-like lesions. While the infection is usually mild and resolves spontaneously in healthy individuals, it may cause more severe symptoms in immunocompromised patients. Preventive measures, such as wearing gloves when handling animals and their tissues, are essential to reduce the risk of transmission to humans. Orf is an ancient disease with documented cases dating back centuries. It has various regional names, such as “scabby mouth” or “sore mouth” in different parts of the world.

Epidemiology

Incidence and Prevalence:

• Orf is widespread in many regions with significant livestock farming, such as sheep and goat-rearing areas. Outbreaks often occur during lambing and kidding seasons.
• The incidence of Orf varies with climatic conditions, animal husbandry practices, and population density of susceptible animals.

Geographical Distribution:

• Orf is found worldwide, with higher prevalence in areas where sheep and goat farming are common.
• The disease is more prevalent in regions with a temperate climate, as the virus can survive for extended periods in the environment under favorable conditions.

Seasonal Variations:

• Orf outbreaks often coincide with lambing and kidding seasons when animals are more susceptible to the virus due to hormonal changes and exposure to infectious materials during parturition.
• Human cases may also show seasonal patterns related to increased contact with infected animals during specific farming activities.

Age and Species Susceptibility:

• Young animals are more susceptible to Orf, and lambs and kids are at higher risk of infection compared to adult animals.
• While sheep and goats are the primary reservoir hosts, other ruminants, such as deer and camels, can also be infected.
• Impact on Livestock and Public Health:
• Orf can cause economic losses in the livestock industry due to reduced productivity, weight loss, and treatment costs for infected animals.
• In humans, Orf typically presents as self-limiting skin lesions. However, immunocompromised individuals may experience more severe symptoms and complications.

Preventive Measures:

• Preventive measures to reduce the risk of Orf transmission to humans include wearing gloves and other protective clothing when handling infected animals or their tissues.
• Vaccination strategies have been developed for livestock to control the spread of virus and reduce the impact on animal health.

Anatomy

Pathophysiology

Viral Entry:

• Orf virus enters the host’s body through breaks in the skin, such as cuts, scratches, or abrasions.
• The virus may also enter through mucous membranes if there is direct contact with infected animal secretions.

Replication in the Epidermis:

• Once inside the host, the Orf virus infects keratinocytes, which are the predominant cells in the epidermal layer of the skin.
• The virus utilizes host cell machinery to replicate and produce viral particles.

Formation of Pustules and Nodules:

• As the Orf virus replicates in the infected keratinocytes, the host cells become enlarged and rounded, forming characteristic pustules or nodules.
• These pustules contain a mixture of virus particles, keratin, and inflammatory cells.

Inflammatory Response:

• The presence of virus and viral replication triggers an inflammatory response in the infected skin tissue.
• Immune cells like neutrophils and macrophages, migrate to the site of infection.

Development of Crusts and Scabs:

• Over time, the pustules and nodules progress to form crusts and scabs as the inflammatory response resolves.
• The crusts are composed of keratin, virus particles, and debris from the immune response.

Spontaneous Regression:

• In many cases, the host’s immune response eventually controls the viral infection, leading to the spontaneous regression of the lesions.
• The immune system clears the virus, and the skin gradually heals.

Transmission to Other Hosts:

• Orf is highly contagious and can spread from infected animals to other susceptible hosts.
• Humans can contract Orf through direct contact with infected animals or their tissues.

Etiology

Reservoir Hosts

• Sheep and goats are primary reservoir hosts for the Orf virus. These animals often serve as the source of infection for other susceptible species, including humans.

Zoonotic Potential

• Though Orf primarily affects animals, it can be transmitted to humans, particularly individuals with close contact with infected animals, such as farmers, veterinarians, and butchers. Zoonotic cases of Orf are self-limiting and rarely pose significant health risks to immunocompetent individuals.

Seasonal Variation

• Orf outbreaks often show a seasonal pattern, with higher incidences during the spring and early summer. This increase in prevalence may be associated with the birthing season of sheep and goats when newborns are more susceptible to infection.

Global Distribution

• Orf is prevalent worldwide, occurring in various regions with sheep and goat populations. The infection is more common in rural areas and places where these animals are reared for agriculture.

Risk Factors

• Several factors may increase the risk of contracting Orf, including occupational exposure to infected animals, handling of meat or carcasses from infected animals, and poor hygiene practices during animal husbandry.
• Understanding the etiology of Orf is essential for implementing effective preventive measures, early diagnosis, and appropriate management of the infection in both animals and humans.

Genetics

Prognostic Factors

Immunocompetence

• In immunocompetent individuals, Orf is usually a mild and self-limiting infection. The body’s immune system can mount an effective response to the virus, leading to the resolution of the lesions and a favourable prognosis. However, individuals with compromised immune systems may experience more severe and prolonged symptoms, with a potentially higher risk of secondary infections.

Site and Extent of Lesions

• The location and extent of Orf lesions can influence the prognosis. Lesions on non-weight-bearing areas of the body, such as the hands and arms, have a better prognosis compared to those on weight-bearing areas or areas prone to friction, which may lead to prolonged healing and discomfort.

Secondary Infections

• Secondary bacterial infections at the site of Orf lesions can complicate the clinical course and may lead to delayed healing and more severe symptoms. Prompt management of secondary infections is essential to improve the prognosis.

Hygiene and Wound Care

• Proper wound care and hygiene practices can significantly affect the prognosis of Orf. Keeping the affected area clean & dry helps prevent secondary infections and supports faster healing.

Timely Diagnosis and Treatment

• An early and accurate diagnosis of Orf is crucial for initiating appropriate management. Timely treatment, if necessary, can help alleviate symptoms and reduces the risk of complications, leading to better prognosis.

Occupational Risk and Exposure

• For individuals with occupational exposure to infected animals, such as farmers, veterinarians, and butchers, the risk of contracting Orf may be higher. Awareness of this risk and adherence to preventive measures can influence the prognosis by reducing the likelihood of infection and minimizing its impact.

Clinical History

Age Group

Children:

• Children are often more susceptible to Orf due to their close contact with animals during play or petting.
• Clinical presentation in children may include one or more painful pustules or vesicles on the hands, fingers, or face.
• Itching and discomfort are common complaints in affected children.

Adults:

• Adults who are involved in farming, veterinary work, or butchering are at increased risk of acquiring Orf.
• The clinical presentation in adults is similar to that of children, with painful lesions typically found on the hands, fingers, and forearms.
• The infection may also be transmitted to other parts of the body through self-inoculation or contact with contaminated materials.

Physical Examination

Lesion Characteristics

• Location: Note the distribution of lesions on the patient’s body. Orf lesions commonly occur on the hands, fingers, forearms, and face, as these are often the areas in direct contact with infected animals.
• Number and Distribution: Observe the number of lesions and whether they are isolated or grouped. Orf lesions may appear as solitary or multiple, clustered pustules or vesicles.
• Size and Shape: Orf lesions are typically small, round to oval-shaped pustules or vesicles, which may be raised and filled with clear or cloudy fluid.
• Color: Note the color of the lesions. Orf lesions are usually reddish initially and can become pustular with a white or yellowish center.
• Surface: Evaluate the surface texture of the lesions. Orf pustules may have a crust or scab overlying the center, with surrounding erythema and edema.

Pain and Tenderness

• Inquire about any pain, tenderness, or discomfort experienced by the patient in the affected areas. Orf lesions are typically painful and may cause discomfort during movement or touch.

Regional Lymphadenopathy

• Palpate regional lymph nodes, such as the axillary and epitrochlear lymph nodes, for signs of enlargement or tenderness. Orf infection can lead to regional lymphadenopathy as the body’s immune response attempts to contain the virus.

Assessment of Secondary Infections

• Check for any signs of secondary bacterial infection in the Orf lesions, such as increased redness, warmth, and pus formation. Secondary infections can occur due to scratching or introduction of bacteria into the open sores.

Age group

Associated comorbidity

Immunocompromised Individuals:

• Individuals with compromised immune systems with HIV/AIDS, organ transplant recipients, or undergoing immunosuppressive therapy, may experience more severe and atypical presentations of Orf.
• The infection in immunocompromised individuals may be prolonged, with a higher risk of secondary bacterial infections and potential complications.

Associated activity

Acuity of presentation

Acute Presentation:

• Orf often presents acutely with the sudden appearance of small, red papules that progress to pustules or vesicles.
• The lesions are painful and may be associated with local inflammation and swelling.
• Acute cases typically resolve within a few weeks with appropriate care and wound management.

Chronic or Recurrent Presentation: 

• In some cases, especially in immunocompromised individuals, Orf may present as a chronic or recurrent infection. 
• The lesions may persist for an extended period, and new lesions can continue to appear despite initial healing. 
• Chronic or recurrent cases require close monitoring and may need prolonged treatment to control the infection. 

Atypical Presentation: 

• While Orf typically presents with skin lesions, atypical forms of the disease can occur. 
• In rare cases, individuals may experience systemic symptoms such as fever, malaise, and lymphadenopathy. 
• Atypical presentations can be challenging to diagnose and require careful evaluation. 

Differential Diagnoses

Herpes Simplex Virus (HSV) Infection

• HSV infection can present with similar painful vesicular lesions, especially on the hands and face.
• HSV lesions may be more numerous and may have a more rapid onset than Orf lesions.
• Differentiation can often be made based on the history of recurrent episodes and the appearance of the vesicles.

Varicella-Zoster Virus (VZV) Infection (Chickenpox)

• Chickenpox can cause widespread vesicular eruptions on the body, including the hands and face.
• Unlike Orf, chickenpox lesions are usually in different stages of development (papules, vesicles, pustules, crusts).
• The presence of fever and malaise is more common in chickenpox.

Hand, Foot, and Mouth Disease (HFMD)

• HFMD is caused by enteroviruses, particularly Coxsackieviruses and Enterovirus 71.
• It presents with small, painful ulcers or blisters on the hands, feet, and mouth, resembling Orf lesions.
• HFMD is more common in children, especially those in childcare settings.

Impetigo

• It is a bacterial infection that can manifest as small, red vesicles or pustules that quickly rupture and form honey-colored crusts.
• The infection is usually located on the face, particularly around nose & mouth, but it can also appear on the hands.
• A bacterial culture of the lesion can help differentiate impetigo from viral infections like Orf.

Cutaneous Anthrax

• Cutaneous anthrax is a bacterial infection caused by Bacillus anthracis.
• The primary lesion is a painless, black eschar (scab) surrounded by edema and redness.
• The location and appearance of the lesion can help distinguish it from Orf, but laboratory testing may be required for definitive diagnosis.

Ecthyma

• Ecthyma is a bacterial infection caused by Streptococcus or Staphylococcus bacteria.
• It typically presents as a deep, punched-out ulcer with a yellow or greyish base covered by a thick crust.
• Ecthyma is more common in immunocompromised individuals.

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

Supportive Care

• Pain Management: OTC medications like ibuprofen or acetaminophen help relieve pain & discomfort associated with Orf lesions.
• Rest and Avoiding Irritants: Advise the patient to rest in the affected area and avoid activities or substances that may irritate the lesions.

Wound Management

• Hygiene: Emphasize the importance of good hygiene, including regular handwashing, to prevent secondary infections and reduce the risk of self-inoculation.
• Keep Lesions Clean and Dry: Clean the lesions with mild soap & water, pat them dry, and avoid excessive moisture to promote faster healing.
• Topical Antiseptics: Apply antiseptic solutions or ointments to the lesions to prevent bacterial infections and promote wound healing.
• Emollient Creams or Ointments: Use emollient creams or ointments to soothe the skin and reduce itching during the healing phase.
• Avoid Picking or Scratching Lesions: Instruct the patient not to pick, scratch, or squeeze the lesions to prevent further complications and scarring.

Pharmaceutical Agents 

• Topical Antivirals: In some cases, topical antiviral creams or ointments may be prescribed to shorten the duration and severity of the infection. These agents can be particularly beneficial in immunocompromised patients or when the lesions are extensive.
• Oral Antivirals: Oral antiviral medications may be considered in severe or atypical cases, especially in immunocompromised individuals. This can help reduce the duration and intensity of the infection.

Incision and Drainage (Intervention with Procedure) 

• If there is a large accumulation of fluid or pus within the lesion, incision and drainage may be performed to alleviate pain and promote faster healing. This procedure is reserved for cases where there is a risk of complications or significant discomfort.

Follow-up and Monitoring 

• Schedule regular follow-up visits to monitor the progression of the infection, assess healing, and address any concerns or complications.
• In cases of chronic or recurrent Orf, continued monitoring and appropriate management are essential to ensure a favorable outcome.

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

non-pharmacological-treatment-of-orf-disease

Lifestyle modifications:

• Avoid Direct Contact with Infected Animals: Individuals who work closely with infected animals, such as farmers, shepherds, and veterinarians, should take precautions to avoid direct contact with Orf-infected animals or their tissues, such as skin lesions.
• Use Personal Protective Equipment (PPE): People who handle animals or work in environments where Orf is prevalent should wear appropriate PPE, including gloves and other protective clothing, to minimize the risk of contact with infected materials.
• Practice Good Hygiene: washing hands with soap & water after handling animals or being in contact with their secretions can help reduce the risk of Orf transmission to humans.
• Avoid Touching Lesions: People should avoid touching any skin lesions or sores on animals, as well as their own if they have Orf-like symptoms, to prevent further spread of the virus.
• Avoid Sharing Personal Items: Avoid sharing items such as towels, clothing, or grooming tools with infected animals or individuals who have Orf-like symptoms.
• Keep Wounds Covered: If you have any cuts, abrasions, or open wounds on your skin, keep them covered with a clean bandage to reduce the risk of Orf virus entry.
• Maintain Animal Health: Proper management practices and regular veterinary care for livestock can help prevent the spread of Orf among animals and reduce the risk of zoonotic transmission.
• Raise Awareness: Educating people in farming and animal handling communities about Orf and its transmission can help raise awareness and promote preventive measures.

Use of Topical antiseptics in the treatment of Orf disease

Povidone-Iodine (Betadine):

• Povidone-iodine is a broad-spectrum antiseptic that is effective against bacteria, fungi, and viruses.
• It is commonly used as a topical solution or ointment to cleanse the Orf lesions and reduce the risk of bacterial infection.

Chlorhexidine:

• Chlorhexidine is another effective antiseptic agent with broad-spectrum activity against bacteria and some viruses.
• It is available as a topical solution or gel and can be applied to the affected area to help prevent bacterial growth.

Hydrogen Peroxide:

• It is used to clean wounds and prevent infection.
• It has antiseptic properties and is applied topically to cleanse the Orf lesions.

Silver Sulfadiazine:

• Silver sulfadiazine is an antiseptic cream often used for burn wounds.
• While not specifically indicated for Orf, it may have some benefit in preventing bacterial infection in the open sores.
• Alcohol-based Antiseptics:
• Alcohol-based antiseptic solutions may be used to cleanse the affected area.
• However, they may cause stinging and are not recommended for use on open sores or broken skin.

Use of antivirals in the treatment of Orf disease

• Cidofovir is an antiviral medication commonly used to treat certain viral infections, such as cytomegalovirus retinitis in immunocompromised patients.
• While cidofovir has antiviral activity against a wide range of DNA viruses, including poxviruses like Orf virus, its topical use for Orf is not well-established or widely recommended.
• The safety & efficacy of topical cidofovir for Orf have not been extensively studied, and it is not considered a standard treatment option.

Use of immune response modifier in the treatment of Orf disease

• Imiquimod:
• Imiquimod is the immune response modifier used as a topical treatment for certain skin conditions, such as genital warts and superficial basal cell carcinoma.
• Imiquimod stimulates the immune system, leading to an enhanced antiviral response.
• While some studies have explored the potential use of imiquimod for viral skin infections, including Orf, the evidence is limited and not sufficient to establish its efficacy as a standard treatment.

Use of Intralesional Interferon Injections in the treatment of Orf disease

• Intralesional interferon injections involve injecting the medication directly into the Orf lesions. By administering interferon directly into the Orf lesions, it is believed to enhance the immune response and reduce the duration & severity of the infection. However, it is important to note that the use of intralesional interferon injections for Orf is not considered a standard treatment, and evidence supporting its effectiveness is limited.
• Interferons are cytokines that help regulate the immune response. When injected into the Orf lesions, interferon stimulates the immune system, leading to increased antiviral activity and potentially faster resolution of the infection. Intralesional interferon injections are considered safe, but localized reactions at the injection site like pain, redness, or swelling can occur.

surgical-procedures-involved-in-the-treatment-of-orf-disease

Electrocautery:

• Electrocautery, also known as electrosurgery, uses an electrical current to cut, coagulate, or remove tissue.
• In the case of Orf, the electrocautery device is used to burn off the affected tissue, causing it to be removed and allowing the wound to heal.

Curettage:

• Curettage involves scraping off the top layer of the Orf lesions using a sharp instrument called a curette.
• The procedure helps remove the viral-infected tissue, allowing the wound to heal and reducing the risk of secondary infections.

Cryotherapy:

• It is the use of extreme cold to freeze and destroy the Orf lesions.
• Liquid nitrogen or another cryogen is applied directly to the lesions, causing the affected tissue to freeze and subsequently slough off as the skin heals.
• Cryotherapy can help reduce the size and symptoms of the Orf lesions and promote faster healing.

management-of-orf-disease

Acute Phase:

The acute phase refers to the initial stage of Orf when the lesions are actively developing and causing symptoms.

• Supportive Care: During this phase, the primary approach is supportive care, which involves keeping the affected area clean & dry to prevent secondary infections. Avoiding trauma to the lesions is essential to prevent further damage.
• Symptomatic Relief: Topical treatments, such as emollients or topical corticosteroids, may be used to reduce itching, pain, and inflammation associated with the lesions.

Healing Phase:

The healing phase occurs as the acute symptoms subside, and the lesions begin to resolve and heal.

• Wound Care: Proper wound care is crucial during this phase to prevent complications and promote optimal healing. Keeping the affected area clean and applying sterile dressings can aid in preventing secondary infections.
• Avoiding Infection: It is essential to avoid touching the lesions or scratching them, as this can introduce bacteria and lead to infection.
• Symptomatic Relief: Topical treatments, such as emollients, may continue to be used for symptomatic relief during the healing phase.

Chronic or Recurrent Phase:

• In some cases, especially in individuals with compromised immune systems or atypical presentations, Orf lesions may persist or recur over an extended period.

Multidisciplinary Approach:

• For individuals with chronic or recurrent Orf, a multidisciplinary approach involving specialists, such as dermatologists and infectious disease experts, may be necessary to manage the condition effectively.

Long-term Surveillance:

• Regular follow-up visits with healthcare professionals are essential to monitor the lesions, assess the treatment response, and identify any potential complications.

Medication

Future Trends

Media Gallary

References

www.Orf Disease.ncbi.nlm.nih.gov

www.Orf.dermnetnz.org