Feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) are two viral infections that can affect a cat’s immune system. FeLV spreads more easily through prolonged close contact with infected cats, while FIV spreads mainly through deep bite wounds, usually sustained during fights. No cure currently eliminates either infection, but some infected cats can remain well for years with appropriate veterinary care. This guide explains the signs, testing, vaccination and long-term care.
How Are FeLV and FIV Different?
The two viruses behave differently. FeLV can directly cause anaemia and cancer, while FIV mainly weakens the immune system over time.
What Does Each Virus Do, and How Are They Transmitted?
According to the MSD Veterinary Manual, FeLV spreads through infected saliva and urine, mutual grooming, shared litter trays and food bowls, and bite wounds. Infection usually requires prolonged, repeated exposure. Mother cats can also transmit the virus to their kittens in the womb or through their milk; this is likely the greatest source of infection.
FIV mainly weakens the immune system over time. The MSD Veterinary Manual notes that it spreads mostly through bites. Outdoor cats, male cats and older cats are more likely to be infected.
What Are the Symptoms of FeLV and FIV?
Signs vary widely, and some infected cats appear healthy for a long time.
What Early and Advanced Signs Can Occur?
FeLV signs may include:
- Pale gums from anaemia
- Weight loss or poor appetite
- Repeated or slow-healing infections
- Inflammation of the gums and mouth
- Enlarged lymph nodes
According to the MSD Veterinary Manual, cats with FIV may develop fever and swollen lymph nodes shortly after infection. These signs usually pass, and the cat may seem healthy for months or years. Over time, infections of the gums, skin, digestive tract or urinary tract may become more common.
Which Symptoms Need Same-Day Care?
Contact a vet the same day if your cat has difficulty breathing or very pale gums. Refusing food, weakness, or collapse also needs urgent care.
What Tests Are Used for FeLV and FIV?
Both infections can be screened for with blood tests. FeLV screening tests generally detect viral antigens, while FIV tests usually detect antibodies against the virus. Vetic offers blood testing and diagnostic services; confirm with the clinic team that FeLV/FIV-specific testing is available at your chosen location.
What Does Testing Show and When Might Retesting Be Needed?
A common FeLV screening test is a quick blood test that detects FeLV antigen in the blood. FIV testing usually looks for antibodies against the virus. The MSD Veterinary Manual recommends FeLV testing for:
- All kittens at their first veterinary visit
- Cats before joining a household with other cats
- Cats before their first FeLV vaccination
- Cats who are unwell or may have been exposed
After a recent FeLV exposure, repeat testing may be recommended at least 30 days later. FIV testing may also need to be repeated after recent exposure because antibodies can take time to become detectable. Annual testing may be recommended for cats at ongoing risk of exposure, such as those with outdoor access or who live with an infected cat.
What Does a FeLV-Positive Result Mean?
A positive FeLV screening result can be worrying, but it may need confirmation because screening tests can occasionally produce false-positive results. Your vet may recommend further tests to confirm the result.
What Does a Positive Result Mean for Prognosis and Other Cats?
A positive FeLV screening result does not by itself establish the type or long-term status of infection. FeLV infection can be abortive, regressive or progressive, so your veterinarian may recommend additional or repeat testing. In studies cited by the MSD Veterinary Manual, average survival after FeLV diagnosis was about 2.4 years, but individual outcomes vary, and some cats remain healthy for several years. The disease tends to progress faster in kittens than in adults. The MSD Veterinary Manual advises keeping infected cats indoors to protect their health and reduce spread to other cats.
How Are FeLV and FIV Managed Long Term?
There is no cure for either virus. Treatment focuses on supportive care, early treatment of other illnesses and maintaining quality of life.
What Supportive Care and Monitoring May Be Needed?
The MSD Veterinary Manual recommends vet visits at least every 6 months for cats with FeLV or FIV. Supportive care may include:
- Prompt treatment of any infection
- A complete and balanced diet
- Regular parasite control
- A calm, low-stress home
- Neutering, as advised by your vet
Your vet may also recommend vaccinations against other diseases. Have a Vetic vet assess any signs of illness promptly, as early treatment may help.
Should Your Cat Get the FeLV Vaccine?
FeLV vaccination is recommended for kittens and cats younger than 1 year, while vaccination for adult cats depends on their individual exposure risk.
Which Cats May Benefit and What Are the Vaccine Limitations?
The MSD Veterinary Manual cites 2020 AAHA/AAFP guidelines that classify FeLV vaccination as core for cats under 1 year and non-core for low-risk adult cats. Testing is advised before the first dose, as vaccination does not protect a cat that is already infected.
An FIV vaccine is not routinely available in India. Contact your nearest Vetic clinic to ask whether the FeLV vaccine is available and to discuss whether it is appropriate for your cat.
What Are Some Common Misconceptions About FeLV and FIV?
A positive FeLV test does not always mean a cat will become ill quickly. Both infections can have different courses, and some cats remain well for years with appropriate care.
Can People or Other Species Catch These Viruses?
According to the MSD Veterinary Manual, FeLV does not spread to people, and FIV is not known to infect humans. Both viruses mainly affect domestic and wild cats.
Can an FIV-Positive Cat Live with Other Cats?
Yes, in some households. FIV spreads mainly through deep bite wounds, so cats that live peacefully together without fighting have a low risk of transmission. However, the risk is not zero. Have all cats tested, introduce cats carefully, and consult your veterinarian about whether they can safely share a home.
Conclusion
A FeLV or FIV diagnosis can feel overwhelming. However, many cats continue to enjoy a good quality of life with regular care. Testing, vaccination where appropriate and routine check-ups are important steps. To discuss testing or ongoing care, book a consultation at your nearest Vetic clinic.
FAQs
How Long Can Cats with FIV and FeLV Live?
Many cats with FeLV or FIV can live well for years with appropriate veterinary care and monitoring. According to the MSD Veterinary Manual, the average survival after an FeLV diagnosis is about 2.4 years, although individual outcomes vary. Many cats with FIV remain healthy for months or years.
What Are the Final Stages of Feline Leukaemia?
In advanced stages, a cat may have worsening anaemia, repeated infections, weight loss or cancer. Your vet will help you monitor comfort and discuss quality of life.
How Did My Indoor Cat Get Feline Leukaemia?
Some cats are infected as kittens, often from their mother, before joining a home. Contact with an infected cat may also be a source.
Is Feline Leukaemia Curable in Cats?
No cure is currently available for FeLV infection, but supportive care can help infected cats maintain a good quality of life. Some FeLV-positive cats stay well for a long time.
Is It Safe for a Cat with FeLV to Live with Other Cats?
FeLV can spread between cats through prolonged close contact, including mutual grooming and sharing food or litter areas. FIV is transmitted primarily through bite wounds, so the risk from peaceful cohabitation is different. Your veterinarian can advise on testing, vaccination and household management based on the cats’ individual circumstances.
Is the Feline Leukaemia Vaccine Worth It?
The 2020 AAHA/AAFP guidelines classify FeLV vaccination as a core vaccine for kittens and cats younger than 1 year. For adult cats, vaccination is based on individual exposure risk, such as contact with FeLV-positive or unknown-status cats or outdoor access. Test cats for FeLV antigen before vaccination.
References
Levy, J. K., & Burling, A. (2018, updated 2024, September). Feline leukemia virus (FeLV). MSD Veterinary Manual. https://www.msdvetmanual.com/cat-owners/disorders-affecting-multiple-body-systems-of-cats/feline-leukemia-virus-felv
Tizard, I. R. (2018, updated 2024, September). Feline immunodeficiency virus (FIV). MSD Veterinary Manual. https://www.msdvetmanual.com/cat-owners/disorders-affecting-multiple-body-systems-of-cats/feline-immunodeficiency-virus-fiv
