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Too Many Myth-Understandings About FIV (Feline Immunodeficiency Virus)

For many years, I knew only a tiny bit about FIV. I’ve learned a lot more since 2007, when I first adopted Andy, who tests positive for FIV.

Andy, my first FIV+ cat


When I first met Andy, he was very sick. His health improved dramatically once he was getting regular meals. By the time I adopted him, 2+ years after first meeting him, he was perfectly healthy. He continues to be perfectly healthy despite testing positive for FIV.

Myths about FIV

Myth #1: My cat has FIV if an FIV test says she is FIV+. (In fact, many FIV- cats test as FIV+.)

This is the myth that concerns me most.

Fact: Cats who have been vaccinated against FIV will actually test as FIV+ for the rest of their lives. Cats who are “found” by rescue groups and who test positive for FIV are often euthanized immediately even if they have no symptoms of actually having FIV. This makes me very sad to think of the unnecessary death sentences for cats who have been vaccinated for FIV, who become separated from their people, and end up at an animal rescue organization.

Fact: False positives are very common in FIV testing. Many veterinarians recommend that positive results be confirmed using a second type of FIV test format. The two most common test formats are the western blot or Polymerase chain reaction (PCR) test. The western blot test is considered to be definitive for FIV. If a cat tests negative in either one of these tests, that cat is considered FIV negative.

Fact: Kittens born from FIV+ mothers (or mothers who have been vaccinated for FIV) will test positive for the first few months of their lives. However, very few of these kittens will test positive after they are 6 months old. For more information, visit https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-immunodeficiency-virus.

Myth #2: Being diagnosed as FIV+ is a death sentence. (In fact, FIV+ cats in loving homes rarely experience FIV-related health problems.)

Fact: FIV tests only diagnose the presence of a virus. They do not indicate the presence of any disease. Even if cats are infected with FIV, they may live healthy lives for a decade or longer.

Testing as FIV+ does not mean a cat is going to die from FIV. (It doesn’t even mean they do have the virus, as mentioned in myth #1 above.)

Fact: The American Association of Feline Practitioners has guidelines for FIV management, and these which clearly state that “a decision for euthanasia should never be based solely on whether or not the cat tests positive for FIV.”

Cats who test positive for FIV and who end up at an animal rescue organization are likely to be euthanized even if they have no symptoms of actually having FIV. In that sense, it can be a death sentence.

Fact: Dr. Addie (Lecturer in Veterinary Virology, University of Glasgow) performed a study in which FIV+ and FIV- cats were monitored for ten years, and found that FIV infection did not affect the cats’ life expectancy. A fourteen year study by Maureen Hutchison B.Sc, BVMS, MRCVS (veterinary adviser to the Cat Action Trust) found that FIV-positive cats are more likely to die by being killed in road accidents or to be alive and well into their twilight years than they are to die from any FIV related condition.  A long-term FIV monitoring project by Glasgow Veterinary School found that a higher percentage of FIV negative cats died during the period of the study than FIV positive cats.

Myth #3: FIV+ and FIV- cats should not live together because it’s easy to transmit to others. (In fact, FIV is difficult to transmit.)

Fact: FIV is only transmitted when a cat who has the virus gives another cat a deep bite wound. FIV is not transmitted through cats grooming one another, sharing food and water dishes, sharing litter boxes, or through milk from a lactating queen to her kittens. Sexual contact is not a common method of transmission, although in rare instances it has been known to be transmitted this way. For more than 10 years I’ve lived with both FIV- and FIV+ cats and so far there has been no transmission of the virus. Many animal shelters report that they’ve had the same experience, such as http://www.muchlove.org/the-truth-about-fiv/  ,  http://indyferal.org/index.php?page=fiv-felv , and “FIV: The killer cat virus that doesn’t kill cats” by Morell (full citation below).

Fact: Remember, a cat who tests positive for FIV doesn’t necessarily have the virus. See myth #1 above for more info.

If this article is helpful & you’re able, please consider sending a thank-you tip/donation. Even small donations will help me keep my business running during the travel industry slump that has brought pet sitting to a screeching halt. Thank you! (FYI, for a sliding scale fee starting at $30, I offer consultations to help people solve their specific cat-related issues. Let me know what I can help you with.)

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14 comments to Too Many Myth-Understandings About FIV (Feline Immunodeficiency Virus)

  • Harley's Momma

    Thank you so much for this information! I just had my almost 6 yr. old girl torbie tested and she came back faint positive. :-( The vet said she might have been vaccinated when she was a young kitty, I know she was, I adopted her from a friend who had gotten the cat from a PetSmart. I had vet records but misplaced them recently, so I was going on memory of seeing a FeLK – and FIV – dx. This makes me feel a lot better!!

  • Ivy

    Do you encourage vaccinating FIV+ 100% indoor kitties annually? having read all negative reports of kitties getting tumour at injected area, and other problem. Moreover, vaccination is like introducing virus into their already compromised immune system, am I right?

    • Ivy – That’s a great question for your vet. It’s a tricky question to ask & to get an honest answer to because (1) there are legal requirements for vaccinations & some vets might not want to scoot around those requirements even when it’s in the best interest of one animal’s health, (2) lots of vets are uninformed about what FIV+ really means in practical terms, and (3) many vets will drop you as a client if you do not follow their recommendation.

      My own vet has lots of experience w/ FIV+ cats. She believes some vaccinations are still really important for indoor-only FIV+ cats, but some are fine to skip. She *always* gives me an opportunity to reject her recommendations. We make it clear that I am the person legally responsible for decisions about my cats – especially if it goes against legal requirements set for *her* as a practitioner.

  • Jaki McCarrick

    Hi Kari, fantastic info, thanks. I have 7 cats! One, Paddy, I took in as a stray in June. I got him neutered and as an eye infection would not clear I had him tested for FIV – I got both tests done and each time he came up positive. I am going to keep Paddy – as he is gentle and the only trouble is with one of my other male cats who doesn’t like him and they have scrapped but no bites. I am watching his oveall health and he plays and seems happy – though his purr level is very very quiet. These are my questions – as with humans when we have low immune systems we take Echinacea, Vit C – all that stuff – are there equivalent cat products? And do you think Echinacea itself might work for the feline system? I will try to get these products. My next question is this – can I vaccinate my OTHER cats AGAINST FIV – and what is this vaccination called if so? They have had all jabs already – do these jabs not cover FIV already – probably not, though I am not actually sure about that.

    Also – I was interested to read about the Glasgow Unversity study. Are there any developments do you know in the area of FIV treatment? Do you think they could develop a drug that would AT LEAST stop the FIV infection being transmitted via bites, i.e. stop the INFECTIOUS element in the cat that has it? That way at least people wouldn’t panic about the infected cat being amongst their other cats etc. Also, if the transmission is via BITE wounds – would it be a terrible thing to have the infected cat’s teeth filed a bit? I am just thinking about these things, possible solutions etc.

    Anyway – any help on helping Paddy would very much appreciated.
    ALL the best,
    Jaki McCarrick

    • Thanks, Jaki. I’m happy this post is useful. And lucky Paddy!

      For ideas about supplements to support healthy immune systems, try to find a holistic vet who know about FIV. Aside from that, I’d recommend looking at the FIV info in the books above by Messonnier & Wulff-Tilford. I also like Veterinarians’ Guide To Natural Remedies For Cats by Martin Zucker.

      Yes, you can vaccinate your cats against FIV. For info about it (primarily cautions against it), take a peek here: http://www.marvistavet.com/html/body_fiv_vaccine.html. (The American Assoc of Feline Practitioners even recommends against using the vaccine.)

      All of your questions are excellent & I hope you’re able to find a good holistic vet who knows enough about FIV to be helpful for you & your cats.

    • Jaki – PS – My vet has emphasized the importance of not boosting and not suppressing the immune system. The supplements given to FIV+ cats should merely support the immune system.

      With that in mind, it’s also important when giving these cats any type of medication, that we pay attention to how that medication impacts the immune system. If it causes the immune system to be either underactive or overactive, they shouldn’t be on that medication for very long.

  • Sharon

    That is great news!! The 2 doctors we saw and talked too keep telling me there is no vaccine! Which I know is wrong. Its so frustrating dealing with people who are not educated in thier own field!! Thankful for people like you who help and give the truth
    Question- Will we ever know if she is testing positive for FIV becasue of the vaccine or because she is a carrier?

    • Your vets could do a second test, of a different type, to see if they get another positive. Still not guaranteed, though. Consider taking in copies of the first 2 sources listed above. (Those 2 are written by well-respected veterinarians & will give some basic info to vets who don’t know much about FIV.)… Are the 2 vets at 2 different clinics? If not, maybe try a different clinic?.. And… Don’t get me started on vets who don’t know some very basic info about animal health & well-being – it’s fairly common. (Ugh).

  • Sharon

    Thank you so much for this article. We just rescued a stray the other day and took her to the vet, where we found she is 5 weeks pregnant and had a faint positive for FIV. The way the vet (new one, who we will never use again), spoke with us, we had to send her to the SPCA, because she can not live with our other rescue kitty. We do not want to do this, since we just fell in love with her immediatly. I am concerned about her babies. I know if any of them test positive it will be much harder to have them adopted and we are just unable to take care of a litter. Crossing my fingers that it all works out well!

    • Sharon – Great news: A “faint positive” usually indicates the cat was vaccinated against FIV. So your mama cat probably doesn’t actually have FIV. She had owners who had her vaccinated against it. If the mama is FIV+ her kittens will probably test + for the first 6mo or so even if they are -. Do you know the SPCA’s policies on euthanizing cats brought to them? Many shelters automatically euthanize cats who test positive for FIV. 8-(

  • Carla

    Thanks for this reassuring and smart article. I have felt this way all along once I adopted my FIV+ cat. She has improved greatly since she’s been indoors with me.

  • Beth

    Thanks, Kari. This is great information about a confusing topic.

  • Thanks, Nancy. I’ve written for blogs in the pet industry, but never for a print magazine like Cat Fancy. Nothing wrong with me trying, eh? I appreciate the encouragement. 8-)

  • Nancy

    This is a wonderful article Kari. Have you thought about sending it to a publication like Cat Fancy so more people can learn?

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