Feline leukemia virus (FeLV) is one of the most common infectious diseases in cats. It was first discovered in cats with a form of leukemia. In addition to leukemia, affected cats can develop anemia (a low red blood cell level), cancers, and/or suppression of the immune system.





Transmission and Pathogenesis

Feline leukemia virus (FeLV) is a member of the Gammaretrovirus genus within the Retroviridae family and is one of the most prevalent infectious diseases in cats. It is commonly transmitted through casual contact with salivary secretions, such as licking, mutual grooming, or sharing food and water bowls, earning it the nickname "friendly" cat disease.

Cats typically contract FeLV via the oronasal route. After infection, the virus initially replicates in the lymphoid tissue of the oropharyngeal region. It then spreads through infected monocytes and lymphocytes to other parts of the body. During the primary viremia stage, the virus can invade the bone marrow. Once the bone marrow is infected, secondary viremia may occur, with FeLV-infected leukocytes and platelets circulating in the blood. The virus is excreted in the saliva, nasal secretions, urine, feces, and milk of infected cats.



When a cat contracts FeLV, one of three outcomes can occur: abortive infection, regressive infection, or progressive infection.

Clinical signs

FeLV impacts a cat's body in numerous ways. It is the leading cause of cancer in cats, can result in various blood disorders, and may weaken the immune system, leaving the cat more vulnerable to other infections. In the early stages of infection, many cats show no signs of illness. As the disease progresses, a cat’s health may gradually decline, or the cat may go through alternating periods of sickness and relative well-being.

Common symptoms in FeLV-infected cats include:

Pale gums and other mucous membranes

Enlarged lymph nodes

Infections of the bladder, skin, or upper respiratory tract

Weight loss and/or reduced appetite

Poor coat condition

Progressive weakness and lethargy

Fever

Diarrhea

Breathing difficulties

Reproductive issues, such as sterility in unspayed female cats

Stomatitis, an oral condition that involves gum ulceration



Diagnosis

There are three common tests used to diagnose FeLV:

1. ELISA or rapid test: These tests detect the presence of the p27 core protein of FeLV in the bloodstream.
2. Indirect immunofluorescent antibody (IFA) test: IFA detects viral particles within white blood cells.
3. Real-time PCR or real-time reverse-transcription PCR: Real-time PCR identifies FeLV proviral DNA, while real-time reverse-transcription PCR detects FeLV RNA.

Note

Bioguard’s Qmini PCR can detect FeLV RNA in 90 minutes at your clinics using EDTA-blood as samples..