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Feline herpesvirus

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Vaccination Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Feline herpesvirus is caused by the cat herpesvirus. With the calicivirus, it constitutes the essential part of what we call cat coryza: the Cat coryza sheet describes this complex as a whole, this one is devoted to the herpesvirus. The virus attacks the nose, throat and especially the eyes, where it can damage the cornea. Its particularity is that it never leaves the body: after the first episode, it goes to sleep in the nerves and wakes up due to stress or a drop in defenses. An infected cat is therefore infected for life, with completely normal periods interspersed with relapses.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Sneezing Runny nose Discharge from the eyes Red eyes Fever Loss of appetite Reduction

Sneezing attacks, runny nose, noisy and blocked breathing.

Red and swollen eyes, profuse tearing, glued eyelids when waking up, discomfort in light.

Fever, depression and loss of appetite during the acute phase.

Corneal ulcers may appear: the eye becomes cloudy, very painful, the cat keeps it closed.

During relapses, signs are often limited to one eye or a few days of sneezing.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The infection is caused by feline herpesvirus type 1, which multiplies in the mucous membranes of the nose, throat and eyes.

Most cats encounter this virus young, through contact with their mother or other cats.

After recovery, the virus remains latent in the nerve ganglia. Stress, illness, hospitalization, moving, litter or treatment weakening the defenses can reactivate it.

Community life and stressful situations: shelter, boarding, recent adoption, arrival of a new animal or a baby.

Young age, kittens from community litters.

Absent or incomplete vaccination.

Weakening of defenses: IVF, feline leukosis, chronic illness, immunosuppressive treatment.

Flat-faced breeds, in which tears flow poorly and eye signs worsen more quickly.

Transmission

Direct contact between cats: sneezing, licking, shared bowls and beds.

Indirect contact through hands, clothing, equipment and surfaces; the virus is, however, more fragile in the external environment than the calicivirus and is easily destroyed with common disinfectants.

From the mother to the kittens, very frequently, around weaning.

A carrier cat can release the virus during a phase of stress, without being visibly ill.

Humans and dogs are not affected.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The diagnosis is firstly based on the clinical examination and the history of the cat, in particular the recurrent nature of the episodes.

The eye examination is central: the veterinarian applies a dye which reveals corneal ulcers, invisible to the naked eye.

An eye or throat swab can be analyzed to confirm the presence of the virus, particularly in breeding or shelters.

Screening for FIV and leukosis is often suggested in a cat that often relapses.

Treatment

Treatment aims to get over the course and protect the eyes, because no medication permanently eliminates the virus.

Antiviral medications exist, in the form of eye drops or by general administration, and are reserved for severe eye damage: they are prescribed and monitored by the veterinarian.

Regular local care, with cleaning with physiological serum and appropriate eye drops, limits damage to the cornea.

Never put eye drops intended for humans or left over from previous treatment into a cat's eye: some contain corticosteroids which seriously aggravate an ulcer.

An antibiotic is only useful in the event of a secondary bacterial infection.

Reducing stress is part of the treatment: quiet place, stable routines, feline calming diffuser if the veterinarian advises it.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Vaccination is one of the basic vaccines and remains the best lever.

Limiting the stress of sensitive cats avoids some of the relapses: resting spaces at height, gradual transitions, sufficient bowls and litter boxes.

Isolate any new arrival for a veterinary visit.

Clean and disinfect equipment regularly: the virus has poor resistance to common disinfectants.

Vaccination

Herpesvirus is included in the basic cat vaccine, along with calicivirus and typhus.

The primary vaccination begins in the kitten, with several injections spaced apart, then a booster a year later; the following rhythm depends on lifestyle and is decided by the veterinarian.

The vaccine does not always prevent infection or lifelong carriage, but it greatly reduces the intensity of attacks and the risk of serious eye damage.

Possible complications

Corneal ulcers can deepen, become superinfected and, in extreme cases, cause the eye to be lost.

Chronic rhinitis: The virus damages the internal structures of the nose, leaving permanent sneezing and discharge.

Extension to the lungs in kittens and fragile cats.

Adhesions between the eyelids and the eye in kittens infected very early, before the eyes even open.

Blockage of the tear ducts, causing permanent tearing.

When to see a veterinarian

An eye becomes cloudy, very red, or your cat keeps it closed: consult quickly, an ulcer can worsen in a few hours.

He hasn't eaten for twenty-four hours.

His breathing is fast, difficult, or he coughs.

The signs recur regularly: an assessment allows you to look for a cause of weakening.

A kitten shows the same signs: it deteriorates much faster than an adult.

Prognosis

The acute episode generally resolves within one to two weeks in adults, with appropriate care.

The virus remains present for life: relapses are possible, often shorter and milder than the first episode.

The prognosis depends mainly on the eyes: corneal damage treated early most often heals without sequelae, while a neglected ulcer can cost vision.

Frequently asked questions

Will my cat ever be cured?

The episode heals, but the virus remains dormant in the body for life. Many cats never have a visible seizure again; others relapse during periods of stress. This is not a failure of treatment, it is the way of life specific to this virus.

Why do seizures always come back after moving or retiring?

Stress lowers the immune system and wakes up the sleeping virus. Anticipating changes, keeping familiar points of reference and notifying the veterinarian before a risky period limits these relapses.

Can I use eye drops I have at home?

No, never without veterinary advice. Some eye drops contain corticosteroids which seriously aggravate a corneal ulcer and can cause eye loss. Only an examination with dye allows you to know what you are treating.

Are my other cats at risk of being infected?

Yes, especially if they are not vaccinated. Separate bowls and litter boxes during the active phase, wash your hands between cats and check that the entire household is up to date with their vaccinations.