FELV: Feline Leukemia
Signs, Diagnosis and Treatment of Feline Leukemia Virus (FeLV)
About FeLV
Feline leukemia virus (FeLV) can suppress the immune system, cause cancer, or cause other serious illnesses in susceptible cats. However, infected cats can live many years without issues, and not all infected cats will suffer from serious disease, so a diagnosis of FeLV is not as scary as it may seem initially.
Risk Factors
Cats who have contact with other cats and spend time outdoors are most at risk of contracting FeLV. Kittens are particularly susceptible.
Cats can carry the virus but appear healthy. The virus is secreted primarily in the saliva and nasal secretions, though also found in other body fluids and feces. FeLV is usually spread through mutual grooming or bite wounds, and sometimes though shared food dishes and litter boxes. Mothers can also pass FeLV to their kittens.
The FeLV Infected Cat
The response of cats to infection with FeLV is variable. Some time after infection, the virus typically begins circulating in the bloodstream (called viremia, literally meaning the presence of virus in the blood). At this point, cats can spread the virus to other cats.
Some cats, however, are able to mount an effective immune response, after which the virus is no longer circulating in the blood. These cats may harbor the virus in a latent form, but such cats usually don't develop illness due to the FeLV infection and don't become ill. However, other cats seem unable to clear the virus from the blood stream, and become persistently viremic. These cats are the ones who tend to develop serious complications and illness due to the virus, and eventually succumb to the disease. Kittens are most likely to become persistently viremic.
Signs and Symptoms of FeLV
There are several syndromes that can be associated with FeLV:
Diagnosis of FeLV
There are a couple of tests routinely used to test for FeLV. One test, which can be done with a test kit at vet clinics, is called the ELISA and tests for presence of a specific part of the virus. Cats who test positive should be retested a few months later, as they may revert to a negative statues if they can clear the virus from the blood.
Other laboratory tests can be done as well, such as the IFA. Alone the IFA isn't the best test, but a positive IFA test usually indicates a cat is persistently viremic (i.e. unable to clear the virus from the blood stream). More sophisticated tests to directly identify the virus may become more widely available.
Other laboratory tests and diagnostics are not specific for FeLV but can help determine any effects of the virus and what systems are affected, such as the presence of anemia or cancer.
Treating FeLV
There is no treatment specific for FeLV. Treatment is aimed at managing the secondary diseases. This will depend on what conditions are present, of course, and can include treatments such as chemotheraphy for lymphoma, antibiotics for secondary bacterial infections, blood transfusions for anemia, etc.
A variety of anti-viral drugs and immune modulators have been used, but most studies have shown limited (or no) effects and some anti-viral drugs can have severe side effects in cats. Your vet will make treatment recommendations based on recent case studies and information.
Long term management includes minimizing the risks of secondary infections coupled with proactive medical care to catch problems early, along with protecting other household cats that are not yet infected. Again, your vet will discuss appropriate measures, which include:
Preventing FeLV
Preventing exposure to FeLV positive cats is the best way to prevent infection. This includes keeping cats indoors (or allowing outdoor access only in a secure enclosure), testing any new cats for FeLV before introducing them to the household, and housing FeLV positive and FeLV negative cats separately -- no sharing of food bowls or litter pans.
Vaccination can also help prevent FeLV, though not 100 percent effective. Discuss the benefits and risks of vaccinating your cats with your vet. Cats should be tested before vaccinating them, because once a cat is positive, vaccination is not useful.
Please note: this article has been provided for informational purposes only. If your pet is showing any signs of illness, please consult a veterinarian as quickly as possible.
About FeLV
Feline leukemia virus (FeLV) can suppress the immune system, cause cancer, or cause other serious illnesses in susceptible cats. However, infected cats can live many years without issues, and not all infected cats will suffer from serious disease, so a diagnosis of FeLV is not as scary as it may seem initially.
Risk Factors
Cats who have contact with other cats and spend time outdoors are most at risk of contracting FeLV. Kittens are particularly susceptible.
Cats can carry the virus but appear healthy. The virus is secreted primarily in the saliva and nasal secretions, though also found in other body fluids and feces. FeLV is usually spread through mutual grooming or bite wounds, and sometimes though shared food dishes and litter boxes. Mothers can also pass FeLV to their kittens.
The FeLV Infected Cat
The response of cats to infection with FeLV is variable. Some time after infection, the virus typically begins circulating in the bloodstream (called viremia, literally meaning the presence of virus in the blood). At this point, cats can spread the virus to other cats.
Some cats, however, are able to mount an effective immune response, after which the virus is no longer circulating in the blood. These cats may harbor the virus in a latent form, but such cats usually don't develop illness due to the FeLV infection and don't become ill. However, other cats seem unable to clear the virus from the blood stream, and become persistently viremic. These cats are the ones who tend to develop serious complications and illness due to the virus, and eventually succumb to the disease. Kittens are most likely to become persistently viremic.
Signs and Symptoms of FeLV
There are several syndromes that can be associated with FeLV:
- Suppression of Immune System - increases susceptibility to other infections (viral, bacterial, fungal, protozoal).
- Cancer / Tumors - FeLV is one of the most common causes of cancer in cats; lymphoma is especially common with FeLV infections
- Anemia - low red blood cell count.
- A variety of other FeLV-related conditions can affect different body systems, including kidney disease, inflammation of the small intestines (causing persistent diarrhea), liver disease, reproductive disorders, and neurological disease.
- decreased appetite
- progressive weight loss
- poor coat condition
- enlarged lymph nodes
- fever
- pale gums / anemia / icterus
- inflammation of the gums and mouth (redness, swelling, sores)
- skin infections
- urinary tract infections
- respiratory infections
- diarrhea
- behavior changes
- seizures
- eye disease (redness, swelling, blepharospasm or squinting)
Diagnosis of FeLV
There are a couple of tests routinely used to test for FeLV. One test, which can be done with a test kit at vet clinics, is called the ELISA and tests for presence of a specific part of the virus. Cats who test positive should be retested a few months later, as they may revert to a negative statues if they can clear the virus from the blood.
Other laboratory tests can be done as well, such as the IFA. Alone the IFA isn't the best test, but a positive IFA test usually indicates a cat is persistently viremic (i.e. unable to clear the virus from the blood stream). More sophisticated tests to directly identify the virus may become more widely available.
Other laboratory tests and diagnostics are not specific for FeLV but can help determine any effects of the virus and what systems are affected, such as the presence of anemia or cancer.
Treating FeLV
There is no treatment specific for FeLV. Treatment is aimed at managing the secondary diseases. This will depend on what conditions are present, of course, and can include treatments such as chemotheraphy for lymphoma, antibiotics for secondary bacterial infections, blood transfusions for anemia, etc.
A variety of anti-viral drugs and immune modulators have been used, but most studies have shown limited (or no) effects and some anti-viral drugs can have severe side effects in cats. Your vet will make treatment recommendations based on recent case studies and information.
Long term management includes minimizing the risks of secondary infections coupled with proactive medical care to catch problems early, along with protecting other household cats that are not yet infected. Again, your vet will discuss appropriate measures, which include:
- keep FeLV positive cats indoors - this minimizes the risk of exposure to many infectious diseases and also prevents the spread of FeLV to other cats
- feed high quality nutritious diets
- avoid raw foods, which may carry bacteria or parasites that could cause problems in immunosuppressed cats
- closely watch for changes in health or behavior, and check with your vet if any changes are noted
- schedule a check up for your cat more often than usual, at least twice a year - careful monitoring can help detect problems early
- spay or neuter FeLV positive cats
Preventing FeLV
Preventing exposure to FeLV positive cats is the best way to prevent infection. This includes keeping cats indoors (or allowing outdoor access only in a secure enclosure), testing any new cats for FeLV before introducing them to the household, and housing FeLV positive and FeLV negative cats separately -- no sharing of food bowls or litter pans.
Vaccination can also help prevent FeLV, though not 100 percent effective. Discuss the benefits and risks of vaccinating your cats with your vet. Cats should be tested before vaccinating them, because once a cat is positive, vaccination is not useful.
Please note: this article has been provided for informational purposes only. If your pet is showing any signs of illness, please consult a veterinarian as quickly as possible.