CATS · OWNER EDUCATION
Feline Herpesvirus Infection
Feline herpesvirus causes respiratory and eye disease and can remain dormant after infection. Stress or other illness can reactivate it, so later flare-ups do not always mean a new exposure.
THE SHORT VERSION
What matters for your animal?
Start with the warning signs and when-to-contact sections if your animal is unwell. The same outward change can have several causes, so this guide helps you prepare questions rather than identify a diagnosis on your own.
What is this condition?
Feline herpesvirus causes respiratory and eye disease and can remain dormant after infection. Stress or other illness can reactivate it, so later flare-ups do not always mean a new exposure.
Feline herpesvirus can contribute to recurring eye or upper-airway problems. A flare does not mean that every episode of sneezing or eye discharge has the same cause. Assessment is especially important when an eye is painful or cloudy, because damage to the eye changes urgency and treatment. Support for eating, hydration, and comfort may be needed alongside management of the infection.
Which species does this guide cover?
The species listed above are the focus of this guide, rather than a complete list of every animal that can develop this condition. Causes, testing and treatment may differ between species and individual patients.
Why can it happen?
- Transmission involves infected secretions. Young cats and cats in group housing are commonly exposed.
An infectious illness depends on both the organism and the animal's ability to resist it. Exposure does not always produce the same severity of illness in every animal. Age, previous immunity, nutrition, stress, and concurrent disease can influence the outcome. The infection may also cause complications that need treatment separately from the organism itself. For example, correcting fluid loss or supporting breathing can be essential even when a targeted medicine has already been started.
What might an owner notice?
- Sneezing, watery or thick discharge, red eyes, squinting and poor appetite. Corneal ulcers can threaten vision.
An eye can be painful even when there is little discharge. Holding it partly closed, avoiding light, rubbing the face, or becoming reluctant to move through familiar surroundings can be important clues. Surface injury, inflammation inside the eye, and abnormal pressure can look similar from outside. Looking at a photograph cannot replace examination of the structures and measurements that distinguish them. A sudden change in sight or a painful eye deserves prompt attention because some eye problems progress quickly.
How is the problem investigated?
The veterinarian assesses the eyes and may use fluorescein dye. PCR results are considered with clinical findings because healthy carriers may test positive.
Fluorescein is a dye used to reveal defects in the corneal surface. The pattern of staining helps the veterinarian assess the wound, but it is only one part of the eye examination. Tear production, eyelid position, foreign material, infection, and the depth of injury can influence treatment. Repeating the examination during healing helps determine whether the surface has actually closed. Less squinting is encouraging, but comfort alone does not prove that an ulcer has healed.
What might treatment involve?
Supportive care and selected antiviral treatment can help; painful eye disease needs a specific plan. Treatment is tailored to severity.
This is an overview, not a prescription or a recommendation for a specific individual animal.
What can owners do at home?
Reduce stress, gently clean discharge as instructed and monitor eating. Use eye medicines exactly as prescribed.
A feeding plan should account for the actual food eaten, not just the amount offered. Selective eating, dropped food, hidden leftovers, and competition can make intake difficult to judge. Record the food type, measured portion, treats, and any supplements so the team can assess the complete diet. A disease-specific diet or assisted feeding may be recommended in some cases, but force-feeding is not a safe default for an animal that cannot swallow normally or may have an obstruction.
Avoid actions that could make care less safe.
- Do not use leftover steroid eye drops on an unexamined painful eye or assume all squinting is a routine flare.
What can the longer-term outlook involve?
The virus may persist for life, but many cats have manageable episodes. Eye complications require close follow-up.
A recheck is not simply a repeat of the first appointment. It assesses whether the original problem is improving, whether complications are appearing, and whether the treatment remains appropriate. The useful measures may include comfort, function, intake, body weight, examination findings, or selected tests. Ask which changes are expected before the visit and which should trigger an earlier call. Improvement in one sign does not always mean that every part of the disease has resolved.
Can risk be reduced?
Vaccination reduces severity; quarantine and appropriate cleaning reduce spread.
Disease prevention includes the route by which animals, people, equipment, bedding, feed, or water can carry a problem between groups. Separation works best when it also includes dedicated tools, careful handling order, and an appropriate cleaning plan. A newly arrived animal may appear well while a disease is incubating. Ask which tests or observation period suit the species and suspected disease before mixing groups. Cleaning, disinfection, and disposal requirements differ between organisms, so a single household product is not a universal solution.
When should you arrange care?
- A painful or cloudy eye needs same-day assessment; breathing difficulty or inability to eat requires urgent care.
Seek urgent veterinary advice if you notice:
DO NOT DELAY URGENT CARE- Seek urgent care for breathing difficulty or inability to eat; a painful or cloudy eye needs same-day assessment.
What information helps the care team?
Write down when changes started, what makes them better or worse, actual food and water intake, and all medicines and supplements. Short videos and a medication-label photo can help describe changes that may not appear during the appointment.
How should you understand the tests?
Ask what each proposed test is intended to answer. Some tests identify a cause; others assess severity, organ function or treatment safety. Results are interpreted with the examination and history. A normal result does not exclude every problem, and an abnormal result does not always explain every sign.
Questions to ask before leaving
- What is confirmed, and which other explanations are still being considered?
- What changes should we expect with the proposed plan, and when should we reassess if they do not occur?
- Which observations should I record, and which changes mean I should call sooner?
- What medicine or home-care problems should I report, and what are the instructions for a missed dose or suspected side effect?
- When is the recheck, what will it assess, and whom should I contact after hours?
A care plan may be adjusted as results or the response become clearer. Keep the written instructions and tell the team if cost, handling or administration difficulty makes the plan hard to follow.
Sources behind this guide
Herpesvirus Infection in Cats (Feline Viral Rhinotracheitis) | VCA Animal HospitalsVeterinary, university or animal-health guidance ↗Content last reviewed: October 3, 2026. Review status: veterinary-informed; independent veterinarian review not yet completed.