Feline leukemia virus is a serious and life-altering disease that affects cats worldwide. As one of the leading infectious causes of death in domestic cats, FeLV is something that should be given enough attention.

FeLV is caused by a retrovirus that targets a cat’s immune system, making them vulnerable to other infections and diseases, such as anemia and certain types of cancer. Once inside, the virus disrupts normal cell function, particularly in the immune system, making the cat less capable of fighting off infections and illnesses. 

What makes FeLV particularly concerning is how easily it can spread and infect cats.

This is especially quick in multi-cat households or outdoor environments where cats come into contact with each other frequently. Unlike some viruses that the immune system can clear, FeLV often establishes a lifelong presence in the cat’s body. Because of the severity of the virus, prevention proves to be the most important guard against feline leukemia virus. 

But first, let’s talk more about the FeLV.

How is Feline Leukemia Virus Transmitted?

While the virus is not airborne, FeLV can be easily passed from cat to cat through close contact. 

Here’s how FeLV spreads:

Saliva and Nasal Secretions

The primary method of FeLV transmission is through saliva and nasal secretions. Cats that groom each other are at particularly high risk, as grooming involves close contact and exposure to saliva. 

Sharing food or water bowls is another common way for the virus to spread, as an infected cat may leave behind saliva that other cats come into contact with.

Playful biting or roughhousing between cats can also result in the exchange of saliva, increasing the risk of transmission.

Blood, Urine, and Feces

Though less common, FeLV can be transmitted through blood. Cats that engage in fights, particularly outdoor or feral cats, can transfer the virus through deep bite wounds.

Shared litter boxes can pose a risk if cats come into contact with the urine or feces of an infected cat. While this mode of transmission is rarer, it is still possible, especially in unclean or overcrowded environments.

Birth and Nursing

Pregnant cats infected with FeLV can pass the virus to their kittens while they are still in the womb. This means that a mother cat can transmit the virus just by being pregnant.

This is called vertical transmission.

After birth, kittens can also contract the virus through nursing because the feline leukemia virus is present in an infected mother’s milk. Because kittens have underdeveloped immune systems, they are highly susceptible to the virus and often progress to active infection more quickly than adult cats.

Symptoms of Feline Leukemia Virus 

Because FeLV suppresses the immune system and disrupts normal bodily functions, infected cats often experience a combination of symptoms related to their weakened immune state, blood cell production issues, and the development of associated diseases like cancer. 

Here’s a complete look at the symptoms of a feline leukemia virus infection:

• General Signs. Many FeLV-positive cats initially show non-specific signs of illness. These include lethargy, loss of appetite, fever, and weight loss.

• Anemia. Anemia is one of the most common and serious effects of FeLV. Signs include pale gums and tongue, chronic fatigue, and labored breathing.

• Secondary Infections. Respiratory, gastrointestinal, skin, and oral infections can also come as a result of a weakened immune system.

• Cancer and Tumors. FeLV is closely associated with the development of certain cancers, such as lymphomas.

• Digestive Issues. A FeLV infection can lead to disturbances in your cat’s digestive system and nutrition. This includes chronic vomiting, diarrhea, and poor coat condition.

• Behavioral Changes. Behavioral symptoms can arise due to the physical toll of the virus. This includes isolation, increased irritability, and extreme discomfort.

• Neurological Symptoms. Though less common, FeLV can affect the nervous system, leading to seizures, ataxia, and behavioral changes.

How is Feline Leukemia Virus Diagnosed?

Diagnosing FeLV in cats starts with several diagnostic tests. These tests help veterinarians determine whether a cat is infected and the stage of the infection.

Here are the steps we take to diagnose a feline leukemia virus infection:

ELISA Test

This is the primary test used to screen for feline leukemia virus. It detects antigens in the cat’s bloodstream, which are specific proteins produced by the virus. A small blood sample is taken, and the test is often performed at the veterinary clinic, providing results in just a few minutes. 

ELISA is highly sensitive, meaning it can detect the virus early, even before the cat shows symptoms. 

Immunofluorescent Antibody Testing

The IFA test detects FeLV antigens in white blood cells and platelets. Unlike ELISA, which shows the virus in the bloodstream, IFA indicates whether the virus has spread into the bone marrow, which is a sign of a persistent infection. 

A blood or bone marrow sample is sent to our in-house laboratory, where the antigens are identified using a microscope and fluorescent markers. IFA is highly specific, making it a reliable way to confirm an infection after a positive ELISA test. However, it takes longer to get results because it requires laboratory processing.

Polymerase Chain Reaction

PCR testing is the most advanced and sensitive diagnostic method available. This test detects the genetic material of the feline leukemia virus, allowing it to identify both active infections and latent ones where the virus is present but not actively replicating. 

For this test, a blood or bone marrow sample will be analyzed in a laboratory. 

PCR is particularly useful for cases where other tests provide inconclusive results or when determining if an infection is latent. While PCR is highly accurate, it is also the most expensive and takes the longest to process.

How is Feline Leukemia Virus Treated and Managed?

While there is no cure for the feline leukemia virus, there are ways to manage the disease and improve your cat’s condition. Managing the disease involves treating symptoms, preventing complications, and taking steps to maintain the cat’s overall health. Each treatment step will depend on the symptoms present after your cat has been diagnosed with a FeLV infection. 

Here’s how we can do it.

Medication

Cats with anemia may require medications to stimulate red blood cell production or, in severe cases, blood transfusions to manage their condition.

For cats suffering from secondary infections, the appropriate medications will be used. These infections are treated with antibiotics, antifungal medications, or other medications, depending on the specific illness. 

Cats with lymphoma or other FeLV-associated cancers may benefit from chemotherapy. While not curative, chemotherapy can help reduce tumor size and improve comfort.

NSAIDs and other pain medications can be prescribed to alleviate discomfort, particularly in cats with chronic conditions. Medications or appetite stimulants may help maintain adequate nutrition for cats experiencing weight loss or poor appetite.

Lifestyle and Environmental Management

If your cat has been infected by the feline leukemia virus, it’s important to minimize their exposure to other factors that can worsen its condition. This includes secondary infections. Keep your cat indoors and safe from exposure to diseases and dangers outside.

To further support your cat’s health, a high-quality diet is needed.

Crafting a nutritious diet is key to helping your cat maintain a strong immune system. Upon a checkup, we’ll recommend diets specifically designed for immune-compromised cats. If you need a quick guide, follow our blog on what cats eat.

Routine visits to the veterinarian help monitor the progression of the disease and detect any secondary infections or complications early. Cats with FeLV should see their vet at least twice a year.

Stress can weaken your cat’s immune system, so it’s important to keep your best friend happy and relaxed.

Why Vaccinate Your Cat Against Feline Leukemia Virus?

While there is no specific treatment for FeLV, there is a great way to prevent the virus from infecting your cat. 

This is where vaccinations come into play.

Vaccinating against FeLV drastically improves your cat’s protection against the virus. While it does not guarantee 100% prevention, it’s a huge contribution. The vaccines work to train your cat’s body, helping not only to protect but also to prevent the spread of the feline leukemia virus. This in itself proves to be one of the best ways to safeguard your cat’s health.

Conclusion

Feline leukemia virus is a disease that needs complete understanding and care. Through preventive measures and regular vaccination, you can keep your cat safe from this dangerous disease.