What is Feline Leukemia Virus (FeLV)?

Feline leukemia virus, or FeLV, is a retrovirus that attacks the immune system and red blood cells.

• FeLV causes a variety of diseases in cats.
• It only infects cats and does not pose a risk to humans or other animals.

Signs of FeLV in Cats

FeLV can suppress the immune system, making cats more susceptible to infections and illness. Owners should watch for changes in their cat’s behavior or health.

Common signs include:

• Decreased appetite or anorexia
• Lethargy
• Progressive weight loss
• Frequent sneezing or coughing
• Green discharge from eyes or nose
• Diarrhea or vomiting
• Poor coat condition
• Pale gums
• Eye problems
• Mouth or gum inflammation

Note: Early stages may show no signs at all. Over time, cats may experience cycles of illness and health. FeLV is also a common cause of cancer in cats.

How is FeLV Spread?

FeLV spreads primarily through saliva. Transmission often occurs through:

• Mutual grooming
• Sharing food or water bowls
• Sharing litter boxes
• Fighting

Other fluids that can transmit FeLV:

• Blood
• Urine
• Feces
• Nasal secretions
• Milk (from mother to kittens)

Susceptible cats include kittens and adult cats with weakened immune systems.

Healthy adult cats are mostly resistant to infection.
The virus cannot survive more than a few minutes outside the cat, so casual contact is not a risk.

Diagnostic Tests

• FeLV testing is performed in the vet’s office, taking about 10 minutes.
• Positive tests should be confirmed with a lab test, which takes 3-4 days.
• Kittens may need multiple tests in the first six months of life to ensure accuracy.

Treatment

There is no cure for FeLV. Treatment focuses on managing symptoms:

• Antibiotics for bacterial infections
• Blood transfusions for severe anemia

Vaccination:

• A recombinant FeLV vaccine is available and recommended for kittens.
• Two kitten vaccines plus a booster at one year can almost entirely prevent FeLV.
• Vaccination reduces risk but does not guarantee full protection.

Prevention

Preventing FeLV infection includes:

• Spaying or neutering your cats
• Keeping cats indoors
• Avoiding contact with unknown cats
• Vaccinating kittens that may go outside
• Testing all cats before introducing them into a home
• Separating FeLV+ cats from negative cats
• Not sharing food, water, or litter boxes between infected and uninfected cats

FeLV is easily killed by disinfectants, so a healthy cat can be safely introduced to a house days after a FeLV+ cat has left.

Prognosis

• Many FeLV+ cats can still enjoy several healthy years.
• Average survival after diagnosis is about 3 years, but this varies.
• Regular monitoring of weight, appetite, activity, elimination, mouth, eyes, and behavior is critical.

Keeping Your FeLV+ Cat Healthy

• Keep cats indoors and away from other cats
• Schedule vet checkups at least every six months
• Keep vaccinations and preventives up to date
• Monitor health closely and contact your vet promptly if concerns arise
• Feed a high-quality diet

Public Health Implications

• FeLV cannot infect humans.
• Immune-suppressed cats or humans should avoid close contact with each other, as they can amplify exposure to infections.