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Feline Leukemia Virus (FeLV)

cat with feline leukemia virus (felv)

What is Feline Leukemia Virus (FeLV)?

Feline leukemia virus is a retrovirus that infects cats. FeLV was first documented in domestic cats in the 1960s. Since then it has been discovered in many cats.

Feline leukemia virus (FeLV) can cause a permanent infection that eventually leads to suppression of the immune system, various bone marrow disorders, such as anemia or leukemia, and cancer.

Feline leukemia virus (FeLV)

What Causes FeLV?

The leukemia virus in cats can infect any breed. It is spread by contact from a mother to her kittens across the placenta and through the milk. It may also be spread by blood transfusion. Additionally, it can be spread by equipment that is contaminated with infected blood or other body fluids. It is shed in saliva, tears, urine, feces, and milk. The virus is susceptible to drying, sunlight, disinfectants, and detergents, and it does not survive well in the environment. It can sometimes persist long enough in shared food and water bowls, litter boxes, and on other items to be transmitted to other cats.

Which are the Clinical Signs of FeLV?

Some cats infected with feline leukemia virus (FeLV) have no clinical signs. When a sick cat is diagnosed with FeLV, it may be difficult to determine whether the presenting symptoms are caused by FeLV or some other disease. Fever, lethargy, enlarged lymph nodes (gland), and weakness from anemia may occur.

Some infected cats develop cancer, usually in the lymph nodes or bone marrow. Signs of gastrointestinal diseases, such as weight loss or diarrhea, occur in some cats. Infected cats are often more susceptible to other viruses and bacteria. They may also show signs of multiple infections such as skin lesions, coughing, vomiting, diarrhea, and others. Female cats may give birth to unhealthy kittens and can even fail to carry their kittens to term.


How are Cats Diagnosed with FeLV?

Routine laboratory tests and X-rays are often recommended to investigate the signs of the leukemia virus in cats. Testing is also done prior to vaccination against FeLV. Since cats can be asymptomatic and transmit the infection to other cats, it is recommended that they are tested for FeLV. General misconceptions surrounding what the feline leukemia virus is can also present problems.

Different feline leukemia test results

Which are the Treatment Options?

Some infected cats appear to spontaneously clear the infection or reduce the number of virus particles to such a low level that many FeLV tests are negative and the cat remains healthy. No treatment is proven to eliminate FeLV infection completely. Some antiviral drugs and immune-modulating drugs have been tried, but no treatment is curative.

The prognosis for feline leukemia virus (FeLV) depends on the immune system of the cat, the level of exposure to the virus, and its vaccination history. Diseases caused by FeLV are very serious, and it is estimated that fewer than 20% of persistently infected cats will survive more than three years.

How Can I Take Care of a Cat with Feline Leukemia Virus (FeLV)?

A healthy FeLV-positive cat DOES NOT need to be euthanized. Just look at some of the success stories that have been shared with NHV Natural Pet Products, like Hunter Ray’s story, Mika’s story, and Buddy’s story. However, it is important to keep the cat inside, isolated from other cats, and vaccinated. Regular visits to the veterinarian are very important. This becomes even more important if the cat develops any signs of disease.  

The diet also plays a very important role in maintaining the health of a cat with the leukemia virus. Offering a balanced diet that includes high-quality protein, vegetables, antioxidant-rich fruits, and fresh water is helpful. A raw diet may not be suitable if your cat has FeLV, as it may increase the risk of bacterial infection and malnutrition.