FIV and FeLV: What Does it Mean for Your Cat

FIV and FeLV: What Does it Mean for Your Cat

Every cat parent wants their kitty to be happy and healthy. So, if you’ve heard about Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV), two common infectious diseases in cats, you might feel afraid for your furry friend. Although caused by distinct viruses, these diseases have similarities: both are contagious and incurable. But there’s good news: Understanding these viruses is the first step to keeping your cat healthy! That’s why we’ve rounded up everything you need to know about FeLV and FIV. 

What is FeLV?

FeLV is a feline retrovirus that can affect cats of all ages. A retrovirus is a virus that uses RNA as its genetic material, rather than DNA. FeLV is one of the most common infectious diseases in cats, affecting between 2-3% of all cats in the United States and Canada.

FeLV Transmission

FeLV used to be called the “loving disease” because it was believed that cats could become infected after touching noses with other cats. However, it is now known that FeLV can also be transmitted in the following ways: 

  • Saliva
  • Blood
  • Urine
  • Feces
  • The milk of an infected mother cat
  • From mother to kitten during birth

Symptoms of FeLV

What can be tricky about FeLV is the disease can vary greatly between cats; it may be dormant and not cause outward health issues in one cat, but may cause serious illness in another. 

FeLV breaks down a cat’s immune system, leading to symptoms that include pale gums, jaundice, anemia, weight loss, and poor coat condition. Infected cats may also have an increased risk of bone marrow suppression, which can predispose them to developing other infectious diseases, and various cancers–including lymphoma.

What is FIV?

FIV is another common and consequential infectious disease in cats around the world. In North America, approximately 2.5-5% of cats are infected with FIV. In infected cats, FIV attacks the immune system, leaving the cat vulnerable to many other infections.


The primary mode of transmission for FIV is through bite wounds from an infected cat. Casual, non-aggressive contact, such as sharing water bowls or mutual grooming, does not appear to be an efficient route for spreading the virus. Because FIV is transmitted through bite wounds, cats with outdoor access, especially those who are likely to fight with other cats, are at the greatest risk for FIV infection. 

FIV Symptoms

Although cats infected with FIV may appear normal for years, they eventually suffer from immune deficiency, allowing normally harmless bacteria, viruses, protozoa, and fungi found in the everyday environment to cause severe illnesses.

FIV has highly variable clinical signs that include:

  • Fever
  • Anemia
  • Weight loss
  • Diarrhea 
  • A high risk for secondary infections

Treatment and Prevention

Unfortunately, there is currently no definitive cure for FeLV or FIV. However, cats infected with FeLV/FIV can live very normal, healthy lives for many years if managed appropriately. Veterinarians treating and managing FeLV/FIV-positive cats usually treat specific symptoms. For example, by prescribing antibiotics for bacterial infections, or performing blood transfusions for severe anemia. 

The only sure way to protect healthy cats from these diseases is to prevent their exposure to infected cats. Keeping your cat indoors and away from potentially infected cats is recommended. There is currently no vaccine commercially available to protect against FIV. There is a vaccination for FeLV available but it may not eliminate the risk of infection 100%. It is recommended to reduce the risk of FeLV infection for cats at risk of exposure, such as indoor/outdoor cats. 

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