Feline Herpesvirus Infection, FHV (Feline Cold Caused by Herpesvirus Infection) in cats
- Occurrence: common
- Location of illness: General/Whole body, Head/Neck
Feline Herpesvirus Infection (FHV) is a viral disease in cats that primarily affects the upper respiratory tract and is commonly known as part of the feline cold complex.
The most important facts at a glance
Feline Herpesvirus Infection (FHV), also known as feline cold, is caused by a highly contagious DNA virus that spreads mainly through direct contact with infected cats or contaminated objects. Young, old, or immunocompromised cats are particularly at risk. After infection, the virus attacks the mucous membranes of the respiratory tract and can cause symptoms such as sneezing, nasal discharge, and conjunctivitis. The virus can remain latent in the body and become active again under stress or when the immune system is weakened.
The diagnosis is based on clinical symptoms, and a definitive confirmation can be made by PCR tests. Treatment focuses on relieving symptoms and supporting the immune system, as there is no specific antiviral therapy. If necessary, fluid therapies and antibiotics are used against secondary bacterial infections. For prevention, vaccination is one of the most effective measures to reduce the risk of infection. Regular cleaning measures and stress reduction also contribute to prevention.
The prognosis is usually good, with most cats recovering within one to three weeks. However, some cats may remain carriers of the virus and show symptoms again during stress. Chronic eye problems or respiratory diseases can be long-term complications that require ongoing treatment. Regular veterinary check-ups are important to monitor the cat’s health.
Causes
The Feline Herpesvirus, also known as Feline Rhinotracheitis Virus, is a DNA virus from the family Herpesviridae. It is highly contagious and spreads mainly through direct contact with infected cats or contaminated objects. The virus is widespread worldwide and affects cats of all ages, although young kittens, older cats, and immunocompromised animals are particularly susceptible.
After infection, the virus penetrates the mucous membranes of the upper respiratory tract, where it multiplies and causes symptoms such as sneezing, nasal discharge, and conjunctivitis. A special feature of herpesviruses is their ability to enter a latent state. This means that the virus can remain in the cat’s body without causing immediate symptoms. Under stress or when the immune system is weakened, the virus can be reactivated, leading to a renewed outbreak of the disease.
The main route of transmission is direct contact with infected secretions, such as nasal or eye discharge. Indirect transmission can occur through contaminated food and water bowls, bedding, or toys. Since the virus is not viable in the environment for long, direct transmission plays a greater role.
Symptoms
The symptoms of FHV infection are usually mild to moderate, but can cause serious complications in severe cases or in untreated animals. The most common symptoms include sneezing, nasal discharge, eye discharge, and conjunctivitis. These symptoms usually appear 2 to 6 days after infection.
In addition, affected cats may show fever, loss of appetite, and lethargy. In severe cases, pneumonia may occur, which is characterized by cough and respiratory distress. Chronic infections can lead to the formation of ulcers on the cornea of the eyes, which is known as herpesvirus-induced keratitis.
In kittens, the infection can be more severe because their immune system is not yet fully developed. In rare cases, a generalized infection can occur, which is difficult to treat and has a high mortality rate.
Diagnosis
The diagnosis of FHV infection is usually based on clinical symptoms and a thorough medical history. The veterinarian will examine the cat and look for typical symptoms such as nasal and eye discharge. A definitive diagnosis can be made by detecting the virus in swabs from the eyes, nose, or throat using PCR (polymerase chain reaction) or virus isolation.
Although serological tests are available, they are often less helpful because many cats have antibodies against FHV due to previous infections or vaccinations. In some cases, cytology or biopsy of the affected mucous membranes may be helpful to rule out other causes of the symptoms.
Therapy
The treatment of FHV infection primarily aims to alleviate symptoms and avoid complications. There is no specific antiviral therapy that can directly kill the virus, so treatment focuses on supporting the immune system and relieving symptoms.
Fluid therapy may be necessary for dehydrated or severely affected cats. Secondary bacterial infections, which often occur with viral respiratory diseases, can be treated with antibiotics. Ointments or drops can be used to relieve the ocular inflammation.
Antiviral drugs such as famciclovir may be used in severe cases or chronic infections to reduce the viral load. Immune system-supporting measures such as L-lysine supplementation can also help control symptoms and promote recovery.
Prognosis and follow-up care
The prognosis for cats with FHV is generally good, especially with early diagnosis and treatment. Most cats recover completely within one to three weeks. However, some cats may remain carriers of the virus and show symptoms again during stress or illness.
Chronic eye problems or recurrent respiratory diseases may occur in some cats, especially those with weakened immune systems or other health problems. These long-term complications may require ongoing treatment and monitoring.
Prevention
To prevent Feline Herpesvirus Infection (FHV) in cats, one of the most effective measures is vaccination. Regular vaccinations help to significantly reduce the risk of infection and also protect against severe disease progression. It is important to discuss the vaccination schedule with the veterinarian and ensure that the cat receives all necessary boosters.
The environment also plays a crucial role in prevention. A clean and hygienic environment can curb the spread of the virus. Regular cleaning of food and water bowls, sleeping areas, and litter boxes is essential. In addition, cats that may be infected should be separated from healthy animals.
Stress reduction is another important factor. Stress can weaken the immune system and make cats more susceptible to infections. A stable and stress-free environment can help strengthen the cat’s immune system. This also includes addressing changes in the household, such as new pets or moves, slowly and carefully.
Pet owners should also ensure that new cats entering the household are tested for FHV and vaccinated if necessary to prevent transmission to other cats. Regular veterinary check-ups also help to monitor the cat’s health and respond to potential problems early.