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Feline leukemia virus
Feline leukemia is a serious viral disease that progressively weakens a cat's immune system. It can evolve silently for months before visible signs appear. It is one of the leading causes of illness and death in cats worldwide.
What is it?
Feline leukemia is a serious viral disease that progressively weakens a cat's immune system. It can evolve silently for months before visible signs appear. It is one of the leading causes of illness and death in cats worldwide.
The disease is caused by the feline leukemia virus (FeLV), a retrovirus that infects immune system cells and bone marrow in cats. This virus disrupts normal blood cell production and weakens the body's natural defenses.
Cats living in groups, with outdoor access, or in contact with stray cats are more exposed. Kittens and unvaccinated cats also face a higher risk. Living with an infected cat greatly increases the chances of transmission.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Possible signs include weight loss, poor appetite, lethargy, a dull coat, and recurrent infections. Pale gums, swollen lymph nodes, or persistent digestive issues may also be observed. Some cats remain carriers without showing visible symptoms for a long time.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Transmission
The virus is mainly transmitted through saliva, during prolonged contact between cats such as mutual grooming, shared food bowls, or bites. It can also be transmitted from mother to kittens during pregnancy or nursing. The virus does not survive long in the environment.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
If you notice signs suggestive of this disease in your cat, consult a veterinarian promptly for professional advice. Only a clinical examination and appropriate testing can confirm the situation and guide care. Never attempt self-medication.
Prevention
Vaccination is an effective preventive measure, to be discussed with a veterinarian based on the cat's lifestyle. Limiting contact with cats of unknown status and testing new cats before introducing them into the household also helps reduce risks. Regular screening is recommended for at-risk cats.
References
Content reviewed by the TunisieVet editorial team · Updated 08 August 2026
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This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.
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