Feline Friend or Furry Foe? The Contagious Nature of Cat Viruses

The Silent Spreaders: How Contagious are Cat Viruses?

It’s estimated that over 84 million households in the United States own at least one cat. While our feline companions provide endless cuddles and entertainment, they can also carry viruses that put both them and us at risk. In fact, cats can be infected with over 60 different viral pathogens – and some can lead to severe illness or death if left untreated.

In this article, we’ll explore some of the most common cat viruses, how they spread, their symptoms, diagnosis and treatment options. By understanding these viral threats, cat owners can better protect the health of their pets.

Common Cat Viruses

There are several viral infections that commonly affect cats. Some of the most common include:

  • Feline herpesvirus (FHV) – This virus causes feline viral rhinotracheitis, an upper respiratory infection. Symptoms include sneezing, eye discharge, fever, and loss of appetite. It is spread through direct contact with infected saliva, mucus, or eye secretions. Source 1

  • Calicivirus – Another virus that causes respiratory infections in cats. It results in oral ulcerations and upper respiratory symptoms like sneezing and nasal discharge. Spread through saliva and nasal secretions. Source 2

  • Panleukopenia virus – Also known as feline distemper, this virus attacks the intestines and bone marrow, causing vomiting, diarrhea, and a lowered white blood cell count. It spreads through contact with infected feces and bodily secretions. Source 3

  • Feline leukemia virus (FeLV) – A retrovirus that suppresses the immune system, leading to secondary infections, cancer, and bone marrow suppression. Transmitted through saliva, milk, urine, and feces of infected cats. Source 1

  • Feline immunodeficiency virus (FIV) – Similar to HIV in humans, FIV attacks the immune system, leaving cats vulnerable to opportunistic infections. Spread through bites and scratches from infected cats. Source 2


Several common cat viruses can spread through contact with infected cats. Feline calicivirus (FCV) and feline herpesvirus (FHV) transmit through direct contact with saliva, nasal secretions, or eye discharge from an infected cat. These viruses spread rapidly between cats in multi-cat households or shelters. FCV is highly contagious and survives well in the environment. FHV spreads readily between cats in close contact. Though less contagious than FCV, it establishes lifelong latency in cats.

Feline leukemia virus (FeLV) transmits through saliva, nasal secretions, urine, feces, milk from an infected mother cat, or blood from bites. Casual contact spreads FeLV less efficiently than prolonged close contact between cats. Feline immunodeficiency virus (FIV) spreads primarily through deep bite wounds carrying infected saliva. FIV does not spread casually between cats or to people.

Feline panleukopenia virus (FPV) spreads extremely readily between cats through contact with infected feces and vomit. It is very environmentally hardy. A single exposure can infect a cat. FPV is not contagious to people. Toxoplasma gondii parasites transmit to cats through infected prey and to people through cat feces. Proper hygiene prevents human infection. In general, indoor cats have less exposure to contagious pathogens. Vaccines help prevent transmission of common cat viruses within populations. FPV, FCV, and FHV rank among the most contagious cat viruses.



Viral infections in cats can cause a variety of symptoms ranging from mild to severe. Some of the most common symptoms of viral infections in cats include:

  • Sneezing
  • Nasal discharge
  • Watery eyes
  • Ulcers in the mouth
  • Fever
  • Lethargy
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Skin lesions
  • Neurological symptoms like incoordination, seizures, and behavior changes

One of the most prevalent viral infections in cats is feline herpesvirus, which typically causes upper respiratory symptoms like sneezing and nasal discharge. Feline calicivirus is another common virus leading to oral ulcers and respiratory issues (https://www.vet.cornell.edu/departments-centers-and-institutes/baker-institute/our-research/feline-calicivirus). In severe cases, these viruses can lead to pneumonia. Feline leukemia virus and feline immunodeficiency virus weaken the immune system, allowing secondary infections to thrive. This can result in a wide range of non-specific symptoms in cats infected with these retroviruses.

Kittens and cats with weakened immune systems tend to experience more severe symptoms from viral infections. However, even healthy adult cats can become very ill from extremely contagious viruses like panleukopenia/feline parvovirus which can cause vomiting, severe diarrhea, dehydration, sepsis and death.


Veterinarians diagnose cat viral infections through a combination of physical exams, symptom observation, and diagnostic testing. The main diagnostic tests used are:

Blood tests – Blood tests like ELISA, IFA, or PCR can detect antibodies or antigens related to viruses like FeLV and FIV. This allows vets to determine if a cat has been exposed to or infected by a certain virus (VCA).

PCR tests – Polymerase chain reaction (PCR) tests can detect small amounts of viral genetic material in a cat’s blood or other body fluids. This allows for identification of active viral infections (Ott).

Virus isolation – Cell cultures inoculated with samples from a cat can show cytopathic effects if live viruses are present. This definitively diagnoses an active viral infection.

In some cases, vets may prescribe antiviral medications as a diagnostic treatment trial. If the cat responds positively, it supports a diagnosis of a suspected viral illness.


Treatment for cat viruses focuses on providing supportive care and managing symptoms while the cat’s immune system fights the infection. There are no medications that can cure or kill these viruses directly. However, antibiotics may be prescribed by a veterinarian to treat or prevent secondary bacterial infections (VCA Animal Hospitals).

For viral infections like feline calicivirus and feline herpesvirus, the main treatments involve keeping the cat hydrated, ensuring proper nutrition, controlling fever and discomfort, and keeping the nasal passages clear. This supportive care helps the cat’s body heal itself (Cornell Feline Health Center).

Veterinarians may administer intravenous or subcutaneous fluids, nutritional supplements, anti-inflammatories, and fever reducers. Nose and eye drops can help relieve congestion and keep the respiratory tract clear. Nebulization therapy may also be used. Careful monitoring and isolation from other pets is recommended during recovery.

While treatment focuses on managing symptoms, the prognosis for otherwise healthy cats to fully recover from common viral infections is generally good with proper supportive medical care. However, cats with compromised immune systems may have more difficulty fighting the infection on their own.


There are several steps cat owners can take to help prevent viral infections in their cats:

Vaccination is the best way to protect cats against common viral diseases like feline panleukopenia, feline herpesvirus, feline calicivirus, and rabies. Kittens should receive a series of vaccines starting around 6-8 weeks of age, with boosters at one year old. Adult cats need regular booster vaccines every 1-3 years as recommended by a veterinarian (Keeping your cat healthy through disease prevention).

Practicing good hygiene and sanitation helps limit exposure. Litter boxes should be scooped daily and fully cleaned out weekly with mild soap and water. Food and water bowls should also be washed regularly. Any toys, bedding, or other items should be washed or replaced as needed.

Limiting interaction with unknown cats can reduce the risk of contracting an infection. Keep cats indoors or only allow supervised outdoor access. Avoid crowded shelters, parks, or boarding facilities when possible.

Reduce stress for your cat, as stress can weaken the immune system. Provide environmental enrichment with toys, scratching posts, perches, and hideaways. Establish a predictable routine for feeding, playing, and bonding.

Talk to your vet about supplements that may support immune health like probiotics, vitamins, or antioxidants.

Risk Factors

There are several factors that can increase a cat’s risk of contracting a viral infection:

Age – Kittens and senior cats have weaker immune systems, making them more susceptible to viruses like feline panleukopenia and feline leukemia (Rungsuriyawiboon et al., 2022).

Environment – Cats in shelters, boarding facilities, and multi-cat households are at higher risk of exposure due to crowding and poor ventilation (AAHA, 2022).

Stress – Stress can suppress the immune system, making cats more susceptible to viral infections (AAHA, 2022).

Vaccination status – Unvaccinated cats are at much higher risk of contracting preventable viral diseases like panleukopenia, calicivirus, and rhinotracheitis (Rungsuriyawiboon et al., 2022).

Exposure to infected cats – Direct contact with cats carrying viruses greatly increases risk of transmission through bodily fluids, fleas, contaminated objects, etc. (Bienzle et al., 2022).


The prognosis for cats infected with viruses like FIV or feline leukemia virus depends on several factors, including the cat’s age, health status, and treatment received. With appropriate care from a veterinarian, many cats can live comfortably with these chronic viral infections for months or years.

For example, cats diagnosed with asymptomatic FIV may live normal lifespans if they receive regular veterinary care, proper nutrition, and monitoring for secondary infections. One study found a median survival time of 5.4 years after diagnosis for FIV-infected cats receiving supportive treatment (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266056/).

The prognosis is more guarded for conditions like wet feline infectious peritonitis (FIP), which is caused by feline coronavirus mutation. With supportive care, survival times for wet FIP typically range from weeks to months. However, there are some experimental antiviral treatments for FIP that may prolong survival in some cats.

Early detection and treatment of secondary infections can greatly improve prognosis in viruses like feline leukemia. Cats treated for anemia, diarrhea, and other complications can live for years after diagnosis. With a multi-modal approach focused on quality of life, infected cats can still thrive under veterinary supervision.


In summary, while some cat viruses like feline immunodeficiency virus and feline leukemia virus can be highly contagious between cats, others like feline herpesvirus and calicivirus tend to be less contagious but still spread through close contact. Proper prevention methods like keeping cats up to date on vaccines, getting new cats tested for viruses, and limiting exposure to infected cats are key to reducing transmission risk. Cat owners should watch for symptoms like fever, diarrhea, nasal discharge, and consult a veterinarian promptly if illness occurs. Though some viruses can’t be cured, early diagnosis and treatment can help minimize their impact. For more information, talk to your veterinarian or refer to online resources from experts. The key takeaway is to be aware of common cat viruses, how they spread, and how to protect your cat’s health through prevention and early detection.

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