Understanding How Cats Get Feline Leukemia
Feline leukemia virus (FeLV) is a serious viral infection in cats that can lead to numerous health problems, including cancer and immune suppression. Understanding how this disease spreads is essential for cat owners looking to protect their pets.
How FeLV Is Transmitted
The virus spreads mainly through close contact between cats, particularly through infected saliva. Here are the most common ways transmission occurs:
- Mutual grooming between cats
- Sharing food and water dishes
- Sharing litter boxes
- Bite wounds during fights
- Nursing from infected mothers
- In utero transmission
- Rarely, via blood transfusions or contaminated instruments
The virus is also present in urine, feces, nasal secretions, blood, and milk. However, FeLV does not survive long outside the cat's body — usually less than a few hours under normal household conditions. Disinfectants easily inactivate it, so indirect environmental transmission is uncommon.
Cats at Risk
Certain cats are more vulnerable to FeLV than others. Risk factors include:
- Outdoor cats that come into contact with unknown or infected cats
- Multicat households where one or more cats may be infected
- Kittens, due to their immature immune systems
- Cats born to infected mothers
Even apparently healthy cats can shed and spread the virus. Adults may develop some resistance, but kittens are especially susceptible.
Types of FeLV Infection Outcomes
Following exposure to FeLV, a cat’s body can react in several ways:
- Abortive Infection: The immune system eliminates the virus before it becomes established. These cats test negative and are not infectious.
- Regressive Infection: The virus is suppressed and lies dormant, often in bone marrow. These cats generally aren’t contagious unless immunosuppression occurs.
- Latent Infection: A moderate amount of virus is present and detectable with PCR tests, but the cat is not typically contagious unless reactivated.
- Progressive Infection: The immune system fails to control the virus, leading to continuous shedding via saliva and feces. These cats often develop illnesses and spread the virus easily.
Health Impacts of FeLV
FeLV can lead to a host of serious health issues. It is a major cause of cancer (especially leukemia and lymphoma), blood disorders, and immune suppression that leaves cats vulnerable to secondary infections. Other complications include:
- Anemia and reproductive problems
- Neurologic disorders
- Oral diseases like gingivitis and stomatitis
- Chronic diarrhea and vomiting
Because the disease affects various body systems, symptoms can vary and progress over time.
Signs of FeLV in Cats
Watch for these common clinical signs:
- Loss of appetite and weight loss
- Poor coat condition
- Pale or yellow gums (anemia or jaundice)
- Swollen lymph nodes
- Fever
- Chronic infections (skin, mouth, bladder, etc.)
- Lethargy and weakness
- Neurologic changes such as seizures or behavior shifts
Diagnosing the Disease
Blood tests are the main method for diagnosing FeLV, especially the ELISA test, which detects viral proteins in samples from blood, saliva, or tears. Follow-up testing 3–12 weeks later confirms the diagnosis. Two other test types include:
- IFA (Immunofluorescent Antibody) for detecting progressive infection
- PCR (Polymerase Chain Reaction) for detecting viral DNA at low levels
Prognosis and Life Expectancy
Many cats clear the virus and remain healthy. For those with progressive infections, about 85% die within 3–4 years, with a median survival time of around 2.5 years. However, some cats with regressive infections may live long, symptom-free lives.
Treatment and Care
There is no cure for FeLV, but supportive care can manage symptoms and improve quality of life. Treatment options include:
- Antibiotics for secondary bacterial infections
- Appetite stimulants
- Anti-inflammatory drugs
- Blood transfusions for severe anemia
- Chemotherapy for cancers
Regular vet check-ups every 6–12 months are essential. Infected cats should be kept indoors to protect them and other cats.
Prevention Strategies
Preventive measures are key to controlling FeLV spread:
- Routine testing, especially before adopting new cats
- Limit outdoor access
- Separate infected cats from healthy ones
- Do not share food and litter equipment between FeLV-positive and negative cats
- Vaccination — recommended for all kittens and high-risk adult cats
Although no vaccine offers 100% protection, it remains a valuable defense, particularly when combined with reduced exposure risk. Vaccinated cats do not test positive on standard antigen tests.
When to Test for FeLV
Testing is advised in the following cases:
- All kittens at their first vet visit
- Before introducing cats into a home with uninfected cats
- Prior to FeLV vaccination
- If a cat has potential exposure to unknown cats
Living with an FeLV-Positive Cat
With the right management, FeLV-positive cats can still live happy, fulfilling lives. Best practices include:
- High-quality nutrition
- A low-stress home environment
- Regular vet visits for monitoring
- Prompt care for illness signs
By understanding how FeLV spreads and how to protect against it, owners can better ensure their cats live healthy, comfortable lives.
