Published by: Ingrid King. Last Updated on: October 31, 2022 by Crystal Uys

Feline Leukemia Virus (FeLV) is the second leading cause of death in cats, killing 85% of infected cats within three years of diagnosis. The virus affects the cat’s blood, causing various blood diseases.  It also suppresses the cat’s immune system, making it harder to protect against infection by bacteria, viruses or fungi found in our everyday environment that wouldn’t affect healthy cats.  However, feline leukemia does not have to be a death sentence; about 70% of cats who encounter the virus are able to resist infection or eliminate the virus on their own.

How is the virus transmitted?

The virus is transmitted through direct contact from cat to cat.  It only affects cats and cannot be passed to people or other animals.  The primary route of transmission is through saliva and nasal secretions, but it is also present in the urine and feces of infected cats.  Cat-to-cat transfer can occur through bite wounds, but also through grooming.  The virus only lives outside its host for a few hours, and because of this, transference through shared use of litter boxes and food dishes is not as common, but it can occur.

Which cats are affected?

Cats living with infected cats, or with cats with an unknown infection status, are at the greatest risk for contracting the virus, which is why it’s important to always get a new cat tested before exposing her to your exisiting feline family members.  Kittens and young adults are more susceptible than older cats, it appears that resistance to the virus increases with age.

Symptoms

Infected cats show one or more of the following symptoms:

– pale gums
– yellow color in the mouth and whites of eyes
– enlarged lymph nodes
– bladder, skin, or upper respiratory infections
– kidney disease
– weight loss and/or loss of appetite
– poor coat condition
– recurring or chronic illness
– progressive weakness and lethargy
– fever
– diarrhea
– breathing difficulty

Diagnosis

FeLV is diagnosed through a blood test called an ELISA test, which tests for the presence of FeLV antigens in the blood.  This test is highly sensitive and can identify cats with very early infections. Many of these cats will manage to clear the infection within a few months and will subsequently test negative.  A second blood test called IFA detects the second phase of the infection, and the majority of cats with positive results for this test remain infected for life and have a poorer long-term prognosis.

Treatment

There is currently no cure for feline leukemia, and in the past, euthanasia was usually recommended for these cats.  85% of cats infected die within three years of diagnosis, but with regular veterinary check ups and preventive health care, these cats can live with good quality of life for quite some time.

A healthy diet is a requirement as a good foundation.  Conventional veterinary wisdom suggests that feeding a raw diet to immunocompromised cats is contra-indicated due to the potential risk of bacteria or parasites in the diet; however, many holistic veterinarians now recommend a raw diet.   If raw feeding exceeds yours or your vet’s comfort level, a grain-free canned diet is the next best thing.  Other holistic approaches such as high doses of vitamin C, homeopathic remedies or Chinese Herbs can help boost the cat’s immune system.

Conventional medical treatment may include steroids, antiviral drugs such as interferon, chemotherapy drugs, and blood transfusions.  Steroids are used to potentially decrease the number of cancerous lymphocytes in the blood, but since they can also depress the immune system, they may make the cat vulnerable to other diseases.   Antiviral agents may reduce the amount of virus present in the blood of the cat, and they are easier on the body than chemotherapy.  All of these treatments will require assessing the risks of the treatment versus the benefits, and they can put a cat in remission, but will not get rid of the virus.

Prevention and protection

Keeping your cat indoors is the only way to completely protect your cat from the feline leukemia virus.  Outdoor cats and indoor/outdoor cats should be vaccinated with a non-adjuvanted leukemia vaccine to minimize the risk of injection site sarcomas.  New cats or kittens over eight weeks of age should be tested before being introduced into a multicat household.

A positive feline leukemia test does not have to be a death sentence.  Some cats may clear the virus themselves, and for others, proper care can lead to good quality of life for many years.

Photo by Kim Newberg, Public Domain Pictures

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