Occurring worldwide, feline leukemia virus (FeLV) is a viral infection among cats, belonging to a group of viruses known as “oncornaviruses,” explained International Cat Care, an online resource on feline health. These types of viruses cause tumors (cancer) to develop in infected individuals. Cats afflicted with FeLV can develop lymphoma, leukemia, and other tumors.
The major effects of FeLV infection are severe immunosuppression and anemia. More cats will die from these complications than from the development of tumors. A persistently FeLV-infected cat will be more likely to develop clinical disease related to the virus, causing suffering and even death.
FeLV and Feline Immunodeficiency Virus (FIV) In Peninsular Malaysia (2012)
Faruku Bande and colleagues of life science and biomedical journal portal PMC harvested plasma samples from the blood of 368 domestic cats, screening them for evidence of FeLV p27 antigen and FIV antibodies using an immunochromatographic kit. Data on cat demographics and health were gathered using a structured questionnaire. The cats’ demographics and health were evaluated as potential risk factors for FeLV or FIV status.
Of the 368 cats tested, 12.2% (45/368) were positive for FeLV p27 antigen, 31.3% of cats (115/368) were positive for the FIV antibody, and 4.3% (16/368) were observed to have both viruses. FeLV or FIV prevalence was higher in clinically sick (FeLV, 23.2%; FIV, 38.4%) than in healthy cats (FeLV, 5.1%; FIV, 23.6%.). The prevalence was also higher among client-owned (13.1%) than in shelter cats (10.3%).
Several factors were correlated with FeLV and FIV seropositive status. FeLV was higher in male cats (16.1%) than in female cats (7.4%). The risk of FeLV was also higher in aggressive cats (20.7%) than in non-aggressive felines (9.6%). Younger cats (17.9%) were more at risk of FeLV than adults (9.6%).
On the other hand, adult cats (34.7%) were more likely to have FIV seropositive status than younger cats (23.9%). Males (36.1%) were also at risk of FIV than females (25.2%). Consistent with the aforementioned data on FeLV seropositive status, aggressive cats (46%) were shown to be at risk of being FIV seropositive than those who are non-aggressive (26.7%).
Other factors like ownership, breed, and sampling location did not significantly influence FeLV or FIV seropositive status. Bande and colleagues concluded that FeLV and FIV seropositive responses were high among cats in peninsular Malaysia. The study also showed that seropositive status to FeLV and FIV was significantly influenced by several risk factors related to the cats’ demography and health.
FeLV In Domestic Cats From Selected Areas in Harare, Zimbabwe (2014)
Francis Muchaamba and colleagues of Scielo, a bibliographic database, conducted their study at eight randomly selected veterinary surgeries and a cat sanctuary between October 2012 and March 2013. 81 cats were sampled from eight different veterinary clinics, seven cats from one cat sanctuary, and 12 unowned cats.
Of the 100 cats, 41% were positive for the FeLV p27 antigen. FeLV infection was higher in cats that had access to the outdoors (52%) than those that had no access to the outdoors (8%). It was also higher in multicat housing (56.86%) than in single-cat housing (29.73%), as well as in intact (53.79%) than in neutered cats (30.19%).
Muchaambo and colleagues wrote that FeLV 27 prevalence was high in sampled cats, which showed that the infection circulated in cats from some urban areas in Harare. The high FeLV infection rate among cats was of concern due to the immunosuppressive potential of the pathogen.
How Is FeLV Spread?
In a persistently infected feline, large quantities of virus are shed in your cat’s saliva and potentially in its droppings, urine, and milk. The virus is fragile and is unable to survive in the environment for any length of time.
Transfer of the virus between cats may occur from a bite wound, during mutual grooming, and through the shared use of litter boxes and feeding dishes— which is rare, stated Cornell University’s College of Veterinary Medicine, a college dedicated to improving the health and wellbeing of animals and people. Transmission can also occur between an infected mother and her kittens before they are born or while being nursed.
Your cat may be at risk of developing FeLV if it is exposed to infected cats via prolonged close contact or through bite wounds. If you own a kitten, they are more vulnerable to being infected. Healthy cats are also at risk if sufficiently exposed.
What Are the Signs of FeLV?
Your cat may not exhibit symptoms of FeLV during its early stages. As weeks, months, or even years pass, your cat’s health may begin to deteriorate and it may experience repeated bouts of illness and relative health. Common signs of FeLV include loss of appetite, weight loss, poor coat condition, persistent fever, persistent diarrhea, abortion of kittens or other reproductive failures, and more.
A cat infected with FeLV will depend in part on the strain of the virus. There are four different strains and these are termed A, B, C, and T. Some strains may cause your cat to develop immunosuppression while others may cause anemia.
How is FeLV Diagnosed and Treated?
An enzyme-linked immunosorbent assay (ELISA) is often performed first as a screening tool and can be done in your vet’s office. ELISA tests detect the presence of free FeLV particles that are frequently found in the bloodstream during the early and late stages of infection.
After a positive ELISA test, an indirect immunofluorescent assay (IFA) is done to confirm FeLV infection and determine whether your cat has reached the later stages of infection. This test is used to detect virus particles within white blood cells.
Unfortunately, there is no cure for FeLV. But one way to protect your cat from being infected is to keep them indoors and away from potentially infected cats. If access to the outdoors is allowed, be sure to supervise your cat or place it in a secure enclosure to prevent it from wandering and picking fights with other cats.
Another way is to test all cats for FeLV before introducing them into your house, with infection-free cats housed separately from non-infected ones. Food and water bowls should not be shared between infected and non-infected felines.
Supportive therapy may be an option, which may include blood transfusions and drugs to manage anemia. Meanwhile, chemotherapy may be done to manage FeLV-associated lymphomas. Try to maintain a good preventive healthcare program along with routine visits to your veterinarian at least twice a year, including regular worming, flea treatments, and vaccination.
Cats infected with FeLV can survive but you have to closely monitor their health. Preventative measures should be done to prevent your cat from being infected. If abnormalities arise, consult your veterinarian.