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Known infection with feline herpesvirus in cats

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Home care monitor at home and contact your vet if worse

YELLOW for acute episodes with sneezing, nasal discharge, conjunctivitis or mild eye problems. ORANGE for corneal lesions/ulcers, severe eye pain, significant loss of appetite/dehydration. RED for severe respiratory distress or purulent keratitis with suspected perforation.

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Definition

InfectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. with felineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. herpesvirus, also known as FHV-1 or cat flu, is a highly contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. disease that primarily affects the respiratory tractThe respiratory tract includes the organs and structures involved in the breathing process, including the nose, pharynx, larynx, trachea, bronchi, and lungs., eyes and throat area of cats.

Can Occur with the Following Diseases:

Cornea Nigra, Black Corneal Necrosis (Dark Spots on the Eye, Corneal Sequestrum)

Basics and possible causes

Feline herpesvirus belongs to the Herpesviridae family and is specific to cats. It is often mentioned in connection with the so-called cat flu complex, a group of pathogens that cause similar symptoms. The virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. is widespread worldwide and can affect cats of all ages, with young animals and immunocompromised animals being particularly susceptible.

The main transmission route of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. is direct contact with infected cats or their secretions, such as nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. and eye discharge. Since the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. can also persist on surfaces such as food and water bowls, indirect transmission is also possible. StressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being., poor housing conditions and high populationIn veterinary medicine, the term population refers to a group of animals of a particular species living in a specific geographic area or environment. density promote the spread of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..

After infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. can persist in the host’s nerve cells and be reactivated at a later time, leading to recurring symptoms. This reactivation is often triggered by stressful situations or a weakening of the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body..

Typical accompanying symptoms

Eye discharge: A common symptom is watery eyes, which may be accompanied by clear to purulentPurulent refers to pus or the production of pus, which may indicate a bacterial infection. Purulent inflammatory conditions are often painful and may have significant swelling and redness. fluid. This can lead to stuck eyelids.
Sneezing: Infected cats sneeze frequently as the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. irritates and inflames the nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. mucous membranes.
NasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. discharge: Similar to eye discharge, a clear to purulentPurulent refers to pus or the production of pus, which may indicate a bacterial infection. Purulent inflammatory conditions are often painful and may have significant swelling and redness. fluid can also escape from the nose, often accompanied by sneezing.
Fever: Affected cats may develop elevated body temperature, indicating a systemic response of the body to the viral infectionA viral infection occurs when a virus enters the body and infects healthy cells, which can lead to disease symptoms. The severity and type of symptoms can vary depending on the type of virus..
Loss of appetite: Due to the impairment of smell and taste as well as general discomfort, infected cats may eat less or refuse food completely.
Mouth ulcers: In some cases, ulcers can occur in the mouth area, which makes eating even more difficult and can lead to increased salivation.
Lethargy: The general weakening of the body and the discomfort often lead to increased lethargy and withdrawal of the cat.

When to see a vet?

A veterinarian should be consulted if the cat shows symptoms such as persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. eye discharge, severe respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, high fever or loss of appetite that last longer than one to two days. Young kittens and immunocompromised animals are particularly at risk, as symptoms can quickly become more severe.

If the cat shows signs of dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse., such as dry mucous membranes or reduced skin elasticity, veterinary advice is also necessary. In case of recurring symptoms that indicate possible reactivation of the virus, an examination by the veterinarian should also be performed.

Symptom recognition for the pet owner and veterinary diagnostic procedure

For the pet owner, it is important to watch for typical symptoms such as sneezing, nasal and eye discharge. Careful observation of the cat and noting changes in behavior or eating habits can provide valuable information for the veterinarian.

The veterinarian will take a comprehensive medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and perform a physical examination of the cat. If an FHV infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. is suspected, special tests, such as a PCR test to detect viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity. in swabs from the eyes or nose, can be performed. These tests help distinguish feline herpesvirus from other pathogens of the cat flu complex.

In some cases, X-rays may be useful to assess the severity of possible lung involvement. Blood tests can also be performed to determine the cat’s general health status and rule out other diseases.

What the pet owner can do and professional therapy options

The pet owner can immediately take some measures to relieve the cat’s symptoms and prevent the spread of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants.. Good hygiene practices, such as regularly cleaning food and water bowls as well as sleeping areas, are crucial. The affected eyes can be gently cleaned with a damp cloth to remove discharge.

A stress-free environment is important to support the cat’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. This can be achieved by providing a quiet retreat and avoiding changes in the daily routine. Regular provision of fresh water and easily digestible food is also essential to keep the cat well-nourished and prevent dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse..

It is advisable to discuss with the veterinarian the use of supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. dietary supplements or antiviral medications that can help relieve symptoms and shorten the duration of the illness. Vaccinations can help reduce the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in the future, although already infected cats may not be fully protected against reactivation.

Outlook on current research

Current research on felineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. herpesvirus (FHV-1) infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in cats focuses on various aspects, including improving diagnostic methods, developing more effective vaccines and investigating viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. latency. Scientists are working to develop more advanced diagnostic procedures that enable early and precise detection of the virus. This is crucial, as early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. can help control the spread of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. and begin treatment in time to relieve symptoms.

Another focus of research is on improving and developing vaccines against FHV-1. Despite the availability of vaccines, there are still challenges regarding their effectiveness and duration of immunityImmunity is the body's ability to protect itself against infections, diseases, or foreign substances. It can be natural, as with innate immunity, or acquired, as with adaptive immunity, which develops after an infection or vaccination.. Researchers are investigating new vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. formulas that could triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. a stronger and longer-lasting immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens.. These efforts are crucial to reduce the incidenceIncidence refers to the number of new cases of a disease or condition that occur within a specific time period in a specific population group. It provides information about the risk of contracting the disease. of infections and protect the health of cat populations.

The study of viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. latency is another important research area. FHV-1 can remain in a latentLatent refers to a state in which a disease or infection is present in the body, but does not yet show any visible symptoms. Latent infections can become active under certain conditions. state after initialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and later be reactivated under stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. or immunosuppressionImmunosuppression is a state of reduced activity or effectiveness of the immune system. In dogs and cats, immunosuppression can occur naturally or be caused by certain medications, diseases, or medical treatments., leading to renewed symptoms. Researchers are working to understand the mechanisms that contribute to latency and reactivation. These insights could lead to new therapeutic approaches that help prevent viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. reactivation and improve the long-term health of infected cats.

Additionally, the genetic diversity of FHV-1 is being studied, as different strains of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. can cause varying degrees of symptom severity. A deeper understanding of the genetic differences between viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. strains could lead to the development of more targeted treatments. Furthermore, alternative therapeutic approaches, such as antiviral medications and immunomodulatorsImmunomodulators are substances that affect the immune system by increasing or decreasing its activity. They are used in dogs and cats to treat autoimmune diseases, allergies, or as cancer therapy., are being explored to more effectively control the symptoms of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and improve the well-being of affected cats.

Overall, these research efforts aim to deepen the understanding of FHV-1 infections in order to develop better preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies and treatments that improve the quality of life for cats and prevent the spread of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. in cat populations.

Frequently asked questions

What is the most common symptom of FHV-1 infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in cats? The most common symptom of FHV-1 infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in cats is acute respiratory disease, often referred to as ‘cat flu.’ This includes sneezing, nasalNasal refers to the nose and nasal cavities. In veterinary medicine, this can involve examinations, treatments, or diseases affecting the nose of dogs and cats. discharge and conjunctivitis.
Can all cats get FHV-1? Yes, all cats can contract FHV-1, but young animals, cats in stressful situations or those with weakened immune systems are particularly susceptible.
How is FHV-1 transmitted? FHV-1 is mainly transmitted through direct contact between cats as well as through contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. environments and objects. The virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. can also be spread by droplet infectionDroplet infection refers to the transmission of pathogens through small droplets of liquid that are released into the air when infected people Cough, Sneeze, or talk and are inhaled by other people. when sneezing.
Can FHV-1 be transmitted to humans? No, FHV-1 is specific to cats and poses no danger to humans.
What happens if a cat is infected with FHV-1? An infected cat typically shows symptoms of respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. disease, but may also develop fever, loss of appetite and lethargy. In severe cases, pneumonia may occur.
How is an FHV-1 infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. diagnosed? An FHV-1 infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. is diagnosed through clinical symptoms and laboratory diagnostic tests such as PCR tests or viralViral refers to viruses and their effects on the organism. Viral infections in dogs and cats can range from harmless colds to severe, life-threatening diseases. isolation.
Is there a treatment for FHV-1 infections? There is no specific cure for FHV-1, but treatment focuses on relieving symptoms, caring for the cat and supporting the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body., often with antiviral medications and immunomodulatorsImmunomodulators are substances that affect the immune system by increasing or decreasing its activity. They are used in dogs and cats to treat autoimmune diseases, allergies, or as cancer therapy..
How can FHV-1 infections be prevented? The best preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. against FHV-1 is vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases.. Regular vaccinations reduce the risk of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. or mitigate the course of the disease.
Can cats be chronically infected with FHV-1? Yes, cats can be chronic carriers of the virusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants., which remains in latentLatent refers to a state in which a disease or infection is present in the body, but does not yet show any visible symptoms. Latent infections can become active under certain conditions. form in the body and can be reactivated during stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. or illness.
How long does it take for a cat to recover from an FHV-1 infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.? Recovery time can vary, but most cats show improvement in symptoms within 1 to 3 weeks. However, chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. carriers may experience recurring symptoms.