The Purrfect Cure. Treating Your Cat’s Viral Infection


Viral infections are common in cats and can range from mild to life-threatening. Some of the most common viral infections in cats include feline herpesvirus, calicivirus, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and rabies.

These viruses are spread through direct contact with an infected cat via saliva, nasal secretions, urine, feces, or from an infected mother cat to her kittens. Kittens and cats with weakened immune systems are more susceptible. Common symptoms of viral infections in cats include sneezing, runny nose and eyes, ulcers in the mouth, fever, lethargy, vomiting, diarrhea, and neurological signs. However, some cats can carry and spread viruses while showing no symptoms.

While some mild viral illnesses in cats will resolve on their own, others require veterinary treatment and supportive care. Prevention through vaccination is key, especially for deadly viruses like rabies. Routine veterinary visits are important to monitor for viral diseases in cats and prevent spread to other pets and people.

Common Viral Infections

Some of the most common viral infections in cats include:

Feline Herpesvirus

Feline herpesvirus (FHV) is highly contagious and spreads through direct contact and respiratory secretions. It causes upper respiratory infection with symptoms like sneezing, runny nose, eye discharge, loss of appetite, and fever (Source 1).


Feline calicivirus (FCV) also leads to upper respiratory infections with additional symptoms like ulcers in the mouth and on the tongue and paws. It spreads through saliva, respiratory secretions, and contaminated surfaces (Source 2).

Panleukopenia Virus

Feline panleukopenia virus (FPV) targets dividing cells like those in the intestine and bone marrow causing vomiting, diarrhea, fever, and low white blood cell count. It is very contagious and hardy in the environment (Source 3).

Feline Leukemia Virus

Feline leukemia virus (FeLV) suppresses the immune system leading to anemia, cancer, and secondary infections. It spreads through saliva, urine, feces, milk, and fleas (Source 3).

Feline Immunodeficiency Virus

Feline immunodeficiency virus (FIV) progressively destroys the immune system resulting in chronic infections, cancer, and wasting. Transmission occurs through deep bite wounds (Source 1).


Viral infections in cats are highly contagious and spread through contact with an infected cat’s bodily fluids or secretions. The main ways cats transmit viruses to each other include:

  • Respiratory secretions: Viruses like feline herpesvirus and calicivirus spread through respiratory droplets expelled when an infected cat sneezes or coughs. These droplets can be inhaled by other cats.
  • Saliva: Diseases like rabies and feline immunodeficiency virus (FIV) spread through bites and saliva. Sharing food bowls and grooming can also transmit viruses.
  • Feces: Some viruses like panleukopenia are shed in feces and can contaminate shared litter boxes.
  • Fleas and insects: Feline leukemia virus can spread through flea bites.
  • Blood: FIV is commonly spread through deep bite wounds where blood is exchanged between cats.

To limit transmission, isolating infected cats and disinfecting environments is recommended. Vaccines are also available for some viral diseases like panleukopenia, calicivirus, herpesvirus, and rabies to protect healthy cats. However, viruses can still spread rapidly between cats in multi-cat households or shelters.



Common symptoms of viral infections in cats include:

Fever – Cats with a viral infection often develop a fever, which is defined as a body temperature above 102.5°F. The fever is a result of the cat’s immune system responding to fight the virus.

Lethargy – Sick cats tend to have decreased energy levels and may sleep more than usual. Lethargy occurs because the body is focused on fighting the infection.

Sneezing – Viruses like feline herpesvirus and calicivirus typically cause upper respiratory signs. Sneezing is commonly seen as the viruses inflame the nasal passages and sinuses.

Nasal/Ocular discharge – Cats may develop thick nasal discharge or discharge from the eyes as part of an upper respiratory viral infection. This is the body’s attempt to expel viruses from the respiratory tract.

Diarrhea – Some viruses like parvovirus can infect the intestinal tract, leading to diarrhea. The diarrhea can sometimes contain blood or mucus.

Vomiting – Nausea and vomiting may occur with some viral infections, especially in the initial stages. This is often associated with a loss of appetite.

Loss of appetite – Sick cats tend to eat less than normal. The decreased appetite may be due to nausea, altered smell or taste, or overall lethargy.

Neurological signs – Viruses like feline infectious peritonitis (FIP) can cause neurological symptoms like tremors, ataxia, and seizures in some cats as the infection spreads to the brain and spinal cord.


Diagnosing a viral infection in cats starts with a physical exam and medical history. The vet will check for symptoms like fever, lethargy, loss of appetite, and enlarged lymph nodes. They will ask about the cat’s vaccination history and any potential exposure to infected cats.

Blood tests can check for antibodies to specific viruses like feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). The ELISA snap test is commonly used to detect FeLV antigens and FIV antibodies from a blood sample (VCA).

Imaging like x-rays or ultrasound may be used to look for enlarged lymph nodes or other abnormalities. In some cases, a biopsy of lymph nodes or other tissues may be taken to analyze under a microscope.

Polymerase chain reaction (PCR) tests can detect the presence of viral DNA/RNA. PCR testing is available for viruses like feline herpesvirus, calicivirus, coronavirus, and parvovirus (Cornell).


As many viral infections in cats do not respond directly to medication, treatment often focuses on supportive care to relieve symptoms and prevent secondary infections while the cat’s immune system fights the virus. This can include:

– Encouraging rest and reducing stress levels, which supports immune function. This may involve confining the cat to limit activity.

– Ensuring adequate hydration and nutrition. Sick cats may need supplemental fluids administered under the skin or intravenously. Assistive feeding may be required if the cat has difficulty eating.

– Nebulization and coupage to help loosen mucus and open airways.

– Broad-spectrum antibiotics if a secondary bacterial infection is suspected. Common choices include doxycycline or amoxicillin.

– Antiviral medications may be considered in severe cases. Options include feline recombinant interferon omega, an immune system modulator.

– Pain medication if fever, headache, or body aches are present.

For prevention, vaccines are available for some viral infections like panleukopenia and respiratory viruses. Annual boosters help maintain immunity. Vaccines can prevent disease but do not treat active infections.

With supportive care guided by a veterinarian, most cats fully recover from viral illnesses within 1-3 weeks as their immune system clears the infection.

Home Care

If your cat has a mild viral infection, the veterinarian may recommend caring for your cat at home while it recovers. It is important to isolate the infected cat from other pets to prevent disease transmission. The sick cat should be confined to one room, and contact with other pets restricted. All food bowls, litter boxes, bedding, and toys should be separated between infected and non-infected cats.

Thoroughly clean and disinfect any surfaces the sick cat has come into contact with using a dilute bleach solution. Wear gloves when cleaning litter boxes and wash hands afterwards. All bedding should be washed frequently in hot water and bleach.

Monitor your cat’s appetite and litter box habits. Make sure your cat is eating, drinking, urinating, and defecating normally. Contact your vet if you notice any decrease in appetite, activity level, or litter box use, as this may indicate a worsening condition.

Keep your cat warm and comfortable during recovery. Provide soft, warm bedding in a quiet area away from other pets. Using a humidifier can help open airways and make breathing easier if your cat has upper respiratory congestion. Speaking softly and gently petting or brushing your cat can help keep it calm during illness.

Follow up with your veterinarian to monitor your cat’s recovery. Though home care can be effective for mild cases, a worsening condition may require prescription medication or supportive vet care. Watch for any breathing difficulties, discharge, dehydration, or lethargy and contact your vet promptly if noted.


The prognosis for viral infections in cats depends on the specific virus involved. Some viral infections are self-limiting and resolve on their own, while others can become chronic or even fatal if left untreated.

For example, feline calicivirus typically causes mild symptoms that go away within a week as the cat’s immune system clears the infection. Most cats recover fully with supportive care at home (source).

In contrast, feline immunodeficiency virus (FIV) cannot be cured and leads to a chronic infection that weakens the immune system over time. However, FIV-positive cats can live for many years with proper care and monitoring (source).

Feline panleukopenia virus is often fatal if untreated, with a high mortality rate in kittens. However, the prognosis is good if supportive care and anti-viral medications are administered promptly under veterinary supervision.

In general, the earlier viral infections are diagnosed and treated, the better the prognosis for affected cats.


One of the best ways to prevent viral infections in cats is through proper vaccination. Vaccines for common viruses like herpesvirus, calicivirus, and panleukopenia virus are a core part of a cat’s preventative healthcare plan. Kittens should receive a series of vaccines starting around 6-8 weeks of age, with boosters continuing every 2-4 weeks until around 16 weeks old. Adult cats need vaccine boosters every 1-3 years, depending on your vet’s recommendations, to maintain immunity. Vaccination protects cats against disease if exposed to these viruses and reduces the severity of illness if infected. While vaccines are not 100% protective for all cats, they significantly improve the chances a cat’s immune system can effectively respond to a viral infection [1].

Since viral infections spread through direct contact with infected cats, limiting exposure is key. Keep cats indoors, avoiding contact with stray or unvaccinated cats. At shelters, isolate incoming cats and test for viruses before introducing to the general population. Proper sanitation of food bowls, litterboxes, and bedding can also reduce viral spread in multi-cat homes. Additionally, regular vet visits for exams allow early detection and treatment of any signs of viral illness.

When to See a Vet

Most mild-to-moderate viral infections in cats can be managed at home with supportive care. However, there are some signs that indicate your cat needs to be seen by a veterinarian:

  • Lethargy or lack of appetite that persists beyond a few days
  • Fever higher than 103°F that does not respond to medication
  • Eye or nose discharge that does not improve or worsens
  • Neurological signs like loss of balance, seizures, or personality changes

According to the VCA Hospitals, cats with severe illness or complications should be hospitalized and placed in isolation. Prompt veterinary care is crucial for cats exhibiting any of the above symptoms, as they can indicate secondary infections, pneumonia, or other problems requiring urgent treatment (source). Do not attempt to treat these issues at home. Seek veterinary attention right away if your cat’s condition seems to be worsening despite your care efforts.

Scroll to Top