Feline Herpesvirus 1 (FHV-1) Infection in Cats

Young cats with FHV normally present with upper respiratory signs, similar to “having a cold.” Older cats are more likely to present with ocular symptoms. In extreme cases, the persistent damage to the eyes results in scarring and blindness.

Feline Herpesvirus 1 (FHV-1) is a highly contagious but preventable condition, often seen in young or unvaccinated cats, or those in crowded conditions like shelters and feral colonies. Vaccination is highly effective at preventing disease.

Cats that contract FHV-1 generally have mild to moderate symptoms, but a carrier state is common and affected cats often have recurrent disease throughout their lifetime. Cats with a latent infection sometimes develop chronic ulceration and scarring of the corneas which, in extreme cases, results in blindness.

FHV is the condition that results from infection with FHV-1. FHV-1 is shed in secretions from the nose, eyes, and mouth of infected cats. Transmission involves direct or indirect contact with these secretions.

Indirect contact usually involves shared resources such as food and water bowls, toys, or grooming tools.

Diagnosis of FHV involves:

• Physical examination
• Blood work

Definitive diagnosis requires detection of the virus including:

• PCR testing
• Virus isolation

Clinical signs are usually sufficient to suspect a viral upper respiratory tract infection and initiate treatment in most cats.

Treatment options fall into two categories: supportive care and symptomatic treatment.

Supportive care includes:

• Using a warm-air vaporizer or placing the cat in a steamed-up bathroom to relieve congestion
• Warming up moist foods to make them more aromatic and appealing
• Cleaning eye and nasal discharge

Symptomatic treatment includes:

• Antibiotics (secondary infections)
• Fluid therapy
• Probiotics
• Antiviral drugs

Resolution of FHV varies between cats. The virus usually runs its course within less than 2 weeks. FHV-1 sometimes results in a latent infection which leads to recurrence of symptoms, often following stressful events such as household changes or other illnesses.

Some cats with poor immune systems have persistent symptoms such as chronic nasal or eye discharge and require ongoing management.

FHV is highly contagious and prevention focuses on vaccination programs, as vaccines are widely available and significantly reduce symptoms of disease when infection occurs.

Vaccination Programs include:

• Vaccination of breeding cats or pregnant queens to ensure high levels of maternal antibodies
• Vaccination of young cats
• Regular booster vaccinations according to recognized guidelines

Other methods of prevention include:

• Isolation of infected cats
• Regular disinfection of shared resources such as food and water bowls and toys

FHV is a common disease in cats and is particularly seen in unvaccinated cats, crowded living conditions, and feral colonies.

• Supportive care
• Symptomatic treatment
• Antibiotics
• Fluid therapy
• Antiviral medications