Feline Leukemia Virus (FeLV)

The feline leukemia virus (FeLV for short) is the infectious virus that cause most diseases, including cancer, the cat population.

Easy transmission: The virus is spread from cat to cat via saliva and respiratory secretions, using the same plates of food and water, kickbacks and bathroom between cats. Even an infected mother can infect her fetus from the uterus. But the urine and stool do not have much problem of contagion.

Refuges, colonies of stray cats and multi-cat households most at risk of having a cat infected cats living alone at home. Just one cat infected only have to create a problem all over the place.

How the virus works: For the contagion becomes dangerous, the cat needs to be constantly exposed to the virus. Many cats are infected at some point in your life, but if it is not constant, create the antibodies needed to fight it and do not suffer the same for the rest of his life.

So in areas with multiple cats the incidence is higher. If one has it and lives with 3 others, surely everyone is infected.

The virus is divided into 3 subgroups

The most common: • Sub Group A. This attacks the immune system leaving the cat susceptible to many other infections. It is also friendly and likes to join other sub groups.

• Sub group B: Combined with the A takes the cat to develop different types of cancer.

• Sub Group C: The less common but strong responsible for anemias and damage to the bone marrow.

Symptoms and signs of infection: Disease due to harsh initial spread of 2-16 weeks. Symptoms usually not very strong and that is why they are often not detected in time.

Initial symptoms include fever, lack of energy, loss of appetite, vomiting and diarrhea. Symptoms include anemia stronger and swollen lymph nodes.

But if exposure to the virus continues, there are 4 possible scenarios for the cat

• The lucky cat: Cat exposed to the virus but have no symptoms of infection.

• The cat passes trauma: Cat develops transient viremia (virus enters the bloodstream) that infects blood and saliva for a period of 12 weeks. After this stage the jack produces antibodies that neutralize and eliminate the disease. The cat is cured and can not transmit the virus.

• Cat with persistent viremia: Infection Blood and saliva continues for more than 12 weeks. The cat can not fight infection being prone to other diseases that are unfortunately deadly. While still alive, they can spread the virus. About 50% of cats at this stage die within 6 months and 80% dies after 3½ years.

• Cat latently infected: They produce antibodies that eliminate the virus in the blood, but not removed from your body. The virus attacks the bone marrow and immune system. The cat can survive the virus but needs a lot of care and stress free environment. Stress combined with any other disease resulting in new viral loads.

About 30% of cats with persistent viremia related to the virus develop months or even years after being exposed cancer. Lymphosarcoma (malignant tumor of the lymph tissue) is the most common cancer but can water to other parts of the body. Leukemia is another risk. Defined as the uncontrolled growth of white blood cells, it can be accompanied with anemia.

Diagnosis and Treatment: There are 2 ways to diagnose FeLV. The first is, by its acronym in English, ELISA (enzyme-linked immunosorbent assay) and is the test performed by the veterinarian in your office with a cat blood sample. ELISA diagnosed cases of infection or weak in their initial states.

The second test is known again by its acronym in English, as IFA (immunofluorescence assay). This is achieved in laboratories and detects viral infection in white blood cells indicating infection in the bone marrow. It means the cat has persistent viremia plus it is contagious.

Currently there is no effective treatment against feline leukemia. But healthy FeLV positive cat can live a long, normal life but with much care. You must live in the house, carry a maximum parasite control, recommended by the vet feed and no stress.


• There is a vaccine for feline leukemia but is given only to cats living in areas at risk of infection.

• The best prevention is to keep it in house and not fail in their visits to the vet.

• If you’re thinking about adding a cat in your family, make it the test and make sure it is free of viruses before taking it home.

• The virus does not survive outside the cat. Clean and sanitize the dishes of food and water, places where the cat sleeps or transits.

• There is no evidence that the virus can be transmitted to humans. But it is recommended that patients with immune system diseases have no contact with an infected cat. Also pregnant or think may be pregnant, should avoid contact.