What Is Papillomavirus?

Papillomaviruses are viruses that infect the skin (epidermis) and mucous membranes, particularly in the mouth and nose. These viruses are highly resistant to both chemical and physical disinfectants, making them difficult to eliminate. There are several strains of papillomavirus in cats and dogs, and the resulting lesions vary depending on the virus type, the host’s immune status, and the affected anatomical site. As a result, a wide range of skin disorders can affect cats and dogs.

Skin Disorders Associated with Papillomavirus in Cats

Feline Viral Plaques:

• Multiple crusted plaques, sometimes hyperpigmented.
• Commonly located on the trunk but may appear elsewhere.
• Seen mostly in middle-aged to older domestic cats.
• Predisposing factor: Immunosuppression.
• Risk: May become cancerous.

Feline Sarcoid:

• Fibroblastic growths induced by papillomavirus.
• Often found in stray cats from rural areas with exposure to livestock.
• Firm nodules, sometimes ulcerated, growing slowly (up to 2 cm).
• Location: Head, neck, tail, and toes.

Bowenoid Carcinoma In Situ (Bowen’s Disease):

• Crusted, pigmented papules and plaques with erosions.
• Location: Face, shoulders, and limbs.
• Typically seen in cats over 10 years old.
• Predisposing factors: Positive feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) test in 1 out of 5 cases.

Transmission and Progression of Papillomavirus in Cats

Transmission between cats and even to humans is possible. Lesions may invade deeper tissues, especially in areas with thin, lightly pigmented, or sparsely haired skin such as the eyelids, nose, and ears.

Available Treatments

In most cases, skin conditions caused by papillomavirus resolve on their own. However, treatment may be necessary if:

• Lesions do not regress.
• The condition affects the animal’s comfort or normal function.
• There is a risk of malignancy.

Treatment options include:

Surgical Treatment:

• Excision of lesions.

Destructive Therapies:

• Cryotherapy (freezing).
• Laser therapy.

Medications:

• Azithromycin: An antibiotic with potential antiviral activity, used for oral and cutaneous papillomatosis.
• Imiquimod 5%: An immune-modulating cream applied directly to lesions.
• Interferon: An antiviral agent. In dogs, its safety and efficacy are still being evaluated.