FIV/FeLV in Cats – Symptoms, Diagnosis, and Management

FIV/FeLV in Cats Singapore

Feline Immunodeficiency Virus (FIV) and Feline Leukaemia Virus (FeLV) remain as a common and important disease in cats worldwide.

In the beginning of 2020, the American Association of Feline Practitioners (AAFP) published new and revised guidelines for the testing and management of FIV and FeLV infections. We hope that this article will give you some updated information on FIV/FeLV in cats that remain a taboo in our society.

1. What is FIV/FeLV in cats?

Feline immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV):

FIV and FeLV in cats are both incurable and contagious viruses. They affect only cats and cause many types of illnesses as well as death in cats.

Recent studies have shown that in the Asia-Pacific region, the prevalence of FIV is around 13% and FeLV around 6%.

Feline immunodeficiency Virus (FIV)

FIV is more common in male cats who are not neutered and in cats who get into fights. It is found less often in kittens and in neutered adult cats.

The virus is passed through the saliva of the cat and is spread predominantly through biting during a fight.

The virus remains infectious for only minutes in the environment. In moist secretions, the virus may survive until dried. The virus is readily inactivated by soap, disinfectants, heat, and drying. Hence, with good cleaning routines and procedures, transmission through sharing of food and water bowls or even mutual grooming between cats is very low.
Urine and faeces are not major sources of FIV and hence the shared use of litter trays is not significant in the transmission of the virus.

And so…. this is GOOD NEWS for multiple-cat households or for those thinking of adopting an FIV positive cat! As long as the cats live in a peaceful co-existence and have no risk of fighting, it has been proven safe for infected and non-infected cats to live together.

FIV is not transmitted through mating in cats. Transmission of FIV to kittens while in the womb or through nursing from an infected mother have been demonstrated experimentally but appears to be uncommon in naturally infected cats.

A 2014 Veterinary Journal scientific report by Dr Litster AL on Transmission of FIV among cohabiting cats in 2 rescue shelters showed the lack of evidence of FIV transmission despite years of exposure to naturally-infected, FIV-positive cats in a mixed household. It also reported that kittens born to FIV-infected queens were tested negative to the FIV virus after birth.

FIV & humans

Although FIV belongs to the same family as the human immunodeficiency virus (HIV), humans cannot be infected by FIV if one gets bitten or kissed by an FIV positive cat and vice versa.

Feline Leukemia Virus (FeLV)

FeLV is less common in cats compared to FIV. However, compared to FIV, it is more commonly and easily spread among cats who live together. The virus is usually shed in urine, faeces, saliva, nasal secretions and milk. Cats get infected easily through fights, mutual grooming, sharing of food bowls and litter trays. The virus can be passed from an infected mother to her kittens while in the womb or through nursing.

So this means that….
Any cat tested positive for FeLV should be kept isolated from other non-infected cats or housed with other FeLV-positive cats only to prevent the spread of the virus to non-infected cats.

2. Clinical signs of infection from FIV/FeLV in cats

Both FIV and FeLV in cats target a cat’s immune system, making the cat susceptible to many other infections.


A newly infected FIV cat may show transient mild illness, with fever, lethargy, a drop in appetite, or lymph node enlargements. They usually do not last more than a day or two before the cat is back to normal. These early subtle clinical signs may not be noticed by most cat owners.

After the early days of infection, the cat can remain illness free for many months or years. During this stage, these cats can still infect other cats.
Over time, the cat becomes at risk for different infections as the immune system slowly becomes dysfunctional and weakens. Such infections include chronic inflammation of the gums/mouth and chronic or recurrent infections of the eyes, skin or urinary tract. FIV positive cats are five times more likely to get cancer than uninfected cats.

As it can take many years for the virus to become active again, many cats infected with FIV can live long and healthy lives.


When first exposed to FeLV, a cat may not show any signs of illness. There are 3 different outcomes for cats who are exposed to and infected with FeLV:
1) Some cats can clear the virus completely and become FeLV negative.
2) Some cats are able to control the infection, preventing illness.
3) Some cats succumb to the viral infection which causes them to become ill and develop clinical signs such as loss of appetite, weight loss, poor coat condition, persistent fever, low red blood cell count (anaemia) or cancer. These problems can be severe and even fatal.

3. Diagnosis testing for FIV/FeLV in cats

Testing for FIV/FeLV in cats can be done via a simple in-house blood test (usually IDEXX Snap FIV/FeLV Combo Test) requiring less than 0.5mls of blood. This test will take only 10mins to rcun and it will check for the FIV antibody and FeLV antigen.

Why should you test for FIV/FeLV in cats? 

As mentioned above, these viruses have serious effects on your cat’s health. FIV, in particular, is highly contagious amongst cats. Knowing the status of FIV/FeLV in cats is critical as infected cats tend to fall sick more easily due to immunodeficiency. Hence, such cats need to be managed with greater care. The outcome of the test will also impact your decisions relating to your cat’s lifestyle – whether your cat should be kept indoors only or allowed to go outdoors, or whether another cat is suitable to join your family.

There will be times in your cat’s life when your veterinarian will recommend testing:
1) If your cat goes outdoors or fights with other cats
2) If you are planning to vaccinate your cat against FIV or FeLV
3) When your cat is sick
4) When you are planning to adopt another cat into your existing cat family
5) When you are planning to breed your female cat

What happens after testing for FIV/FeLV in cats?

Positive diagnosis does not = death sentence for cats!

A normal life is still possible! Many FIV/FeLV positive cats live years after diagnosis. While it can be scary to find out that your cat has an incurable viral infection, it can be managed and many cats go on to have a good quality of life. Ongoing communication with your veterinarian is the key to helping with FIV/FeLV in cats.

My cat has been tested positive for FIV. What’s next?

In kittens less than 6 months of age, we will recommend retesting them again when they are older than 6 months or to be retested immediately with a FIV PCR test to look for the actual virus instead. This is because FIV antibodies can be transferred to kittens that nurse on naturally infected or vaccinated queens, leading to a false positive result due to the maternal FIV antibodies. Kittens persistently testing FIV antibody positive after 6 months of age are likely to be truly infected.

In adult cats, detection of FIV antibodies is generally indicative of FIV infection.

My cat has been tested positive for FeLV. What’s next?

Most cats exposed to FeLV will test positive within 30 days of exposure. FeLV testing is not affected by maternal immunity or FeLV vaccination. Since the consequences of a positive screening test for FeLV are significant for the cat’s future, additional testing using other test methods such as ELISA or PCR testing or using a different brand of test kit is recommended, especially in low-risk and asymptomatic cats.

If your cat has recently been diagnosed with FIV or FeLV, it is important to get the other cats in your household tested as well.

My cat has been tested negative for FIV or FeLV. What’s next?

If your cat has been tested negative for FIV or FeLV but recent exposure to the virus cannot be ruled out, your vet will need to do a repeat test at least 60 days after the last potential exposure.

4. Management & Prevention of FIV/FeLV in cats

There is no treatment for FIV and FeLV once a cat has been infected.

Apart from managing the secondary infections associated with the viruses, your veterinarian will recommend certain household changes that are important in keeping your infected cat safe:

  • Desexing your cat
  • Keeping your cat indoors to prevent the spread of the virus to other cats and also reduce its risk of exposure to other infectious diseases
  • Feeding a good quality nutritionally balanced and complete commercial diet
  • Avoid feeding raw food or barf diets as the risk of food-borne bacterial and parasitic diseases is likely greater in these potentially immunosuppressed cats
  • A good daily cleaning regime for litter boxes, food and water bowls should be implemented.
  • Ensure that there is adequate food and water bowls and litter trays for all cats in the households.
  • Avoid overcrowding by housing many cats together
  • Stress may play a role in triggering the virus to become active, so steps must be taken to reduce stress in infected cats.
  • Close monitoring by caregivers – taking note of weight, body condition and appetite in particular
  • Regular vet check-ups every 6-12 months are recommended. Do speak to your vet for more specific advice on blood tests, vaccinations and parasite control during your regular check-ups.

As mentioned previously, FIV positive cats can still live together with other non-infected cats but not with FeLV positive cats, as long as the cats live in a non-fighting co-existence. FeLV positive cats however can only live isolated from other non-infected cats, in single cat households or with other FeLV positive cats.

Vaccination with the core vaccines (against Feline Panleucopaenia virus, Herpesvirus, Calicivirus and Chlamydia) should be administered in cats with FIV or FeLV infection as they can develop more severe clinical disease related to panleukopenia virus and upper respiratory tract infections after natural exposure compared with uninfected cats.


In Singapore, there are vaccines available for both FIV and FeLV for cats. They are not considered as core vaccines and are only given in specific situations.

However, there are limitations and side effects associated with these vaccines:
1) These vaccines are not 100% effective. In fact, FIV vaccines have a low protective rate which means the vaccinated cats can still get infected naturally.
2) The FIV vaccine can also affect future FIV testing using the usual in-house test kits.
3) FeLV vaccines have been associated with an increased risk of vaccine-induced sarcomas (cancer) at the site of injection.

It is important to talk to your vet to discuss the pros and cons and whether your pet would be suitable for the vaccine.

FIV/FeLV in Cats Singapore

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) testing and vaccination recommendations for healthy cats in animal shelters and free-roaming populations in North America.

Table adapted from: AAFP 2020 Retroviral Guidelines

In summary…

  • FIV/FeLV in cats remain as common and important infections of cats around the world. However it is not a death sentence to have either. Most infected cats will carry on living a normal life span!
  • Although FIV & FeLV in cats both belong to the same group of viruses, their method of transmission, effects on the cat’s health, management and treatment is different.
  • Regular vet checks are important to pick out early symptoms that can be due to the FIV or FeLV infection, and treatment if implemented promptly will allow the infected cat to have the best chance of living a long and healthy life.
  • Vaccination for FIV and FeLV is available but is currently not recommended as part of the routine vaccination schedule for cats in Singapore.

In-home FIV/FeLV tests with Vetpal

Vetpal is a Singapore-based housecall veterinary service treating animals in the comfort of their homes. We are supported by both NUS Enterprise and Enterprise SG.

Vetpal includes FREE FIV/FeLV tests in our Annual Care Plans for cats! Our annual care plans come with 2 housecall visits and are a hassle-free way of ensuring the essential healthcare needs of your cats and dogs are met.

Find out more about our pricing & services, or simply enquire via WhatsApp!

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