This Year, Be the Person

The holidays: a time for family, food, and fun. I personally love the holidays, but they are an interesting time for rescues. Everything is in high gear – adoptions are up, surrenders are everywhere, and everyone is doing their best to keep up while trying to maintain their personal lives. This time of year, things go nuts – we’re trying to balance our “real” jobs, family, and friends with our work in rescue, and let me tell you, it is not always easy. Requests to take animals have ticked up (because you know, people have to get the pets they no longer want out of the house before the family arrives for the holidays), but on the other hand, adoptions were happening left and right this weekend. Honestly, it’s been a somewhat discouraging year – adoptions and donations were down, but the requests for help were as numerous as ever. In November, we took in 37 cats (out of the literally hundreds of requests for help), and adopted out only 10 – the rest are still in foster homes. Why are we telling you this? Because we just can’t do it alone – we need your help.

We need your donations

to pay for vet care, food, and supplies. None of us at Calvin’s Paws are paid, and 100% of every dollar that you give goes directly to the cats.

We need your time

to foster even just one or two cats. It may not seem like much, but to those one or two cats you help us save, it makes all the difference in the world.

We need you to adopt

and not just the cute fluffy kittens. Open your home to a shy, black, one eyed cat, or a longtimer that has been waiting for their forever home for years, left behind while their friends all got adopted. Just because they’ve been overlooked doesn’t mean that anything is wrong with them – they’re just waiting for their perfect home.

Our volunteers are not heroes. We’re not magical beings with wings and halos and harps and clouds. We have jobs and families and commitments. We have bills to pay and mouths to feed. We didn’t always have the space to foster or adopt – we made the space, because we wanted to. We didn’t start out being able to easily give up our fosters to new families – we developed the skill through years of tears (and wine – lots of wine) when our fosters got adopted. We love our cats like we love our family – every single one of them – but we’ve learned that there are always more cats waiting to be loved. More cats that need us.

So please, this holiday season, be the person that makes a difference. Adopt, foster, donate. Those three little words change the lives of countless animals every year throughout the country. Adopt, foster, donate. That’s what those of us in rescue think about, day in and day out, month after month, year after year. We keep on going, saving as many animals as we can and changing their lives. This year, we hope that you will join us. All you have to do is decide that you want to make a difference, and we will help you do it.

Thank you.

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.

This Year, Be the Person

Pictures or it Didn’t Happen

Why I no longer believe any positive FIV/FeLV test result unless I see it with my own eyes.

I know, I know – I’ve written about this before: one test on one day cannot diagnose a cat with FIV or FeLV. (Missed out on these? Read here. And here. And probably here and here too, for good measure.) Yeah, I’m a little obsessive about FIV and FeLV testing, but with good reason. Here’s the latest story.

A request came in to the main Calvin’s Paws email line to take a cat that had tested positive for feline leukemia. Beautiful cat – young male Maine Coon mix. The finders really wanted to keep him, but didn’t want to put their current cat at risk. So I gave them my standard initial advice:

  1. Have the cat retested. Ideally do another in-house test to rule out test error and if that is still positive, have an IFA test done.
  2. It’s really OK to mix FeLV+ cats with adult, vaccinated, negative cats if you’re OK with a small amount of risk (like, 2% under lab settings with a good vaccine – the whole inactivated ones, not the recombinant subunit crap, but I digress).
  3. Read more about FeLV here and let me know how the cat retests.

The finder was grateful for my advice and made an appointment to take the cat to his vet to be retested. They decided that if the cat was still positive, they didn’t want to take the risk, and asked if I would take the cat if needed. I agreed.

The day of retesting came, and they went to their vet. That night, the finder emailed me and explained that the vet had told them that it wasn’t worth redoing the test now because he would have to be quarantined for another three months and retested again regardless of the results. So no retest at all. Not even an in-house test to rule out test error. Yay.

At this point, I told the finder he could just bring the cat to me. I’m the medical coordinator for the rescue, and so I have the tools (and skills) on hand to do a blood draw and run the in-house test while he waited. Because really, I am a testing freak, and I will test any cat anytime for anyone. If the cat was positive, I would keep the cat. If the cat was negative, he would take the cat home with him and keep him. Deal? Deal.

So the day came, and the finders brought the cat (named Bowie) over to my house. They brought him in a carrier covered in a blanket, which my own personal (negative) cat promptly assumed was for him and sat on top of the carrier, trying to see inside. The finders seemed a little nervous at my cats coming so close, but I explained that they were vaccinated against FeLV, and it took prolonged close contact to spread anyway, so I really wasn’t concerned. They relaxed.


The first thing I did was look through the medical records they had brought with them. It turns out that Bowie had initially been tested at Banfield (not always my favorite place) with an IDEXX Triple Test (definitely not my favorite test). The finder started to tell me the full story of how she found him – he showed up at her old apartment right as she was about to move, so she took him in, took him to Banfield right at the end of the night before they closed, and they tested him and did initial care. The vet initially came in and told her that Bowie had tested positive for FIV, but then came back in the room 20 minutes later and told her that he had actually tested positive for FeLV, so understandably the finder was very suspicious already and anxious to have him retested. Yeah, me too.

I drew blood on Bowie and ran two tests – one was the fairly standard IDEXX Combo SNAP test that tests for FIV and FeLV (NOT the Triple Test). The other was a newer test – the Witness FIV/FeLV test made by Zoetis. When we have a cat that has tested positive before, I typically run both tests – just another way to help rule out test error. The Witness test typically comes up faster than the SNAP test, and guess what? So far, Bowie was NOT FeLV+, he was FIV+! The Witness tests are clearly labeled – one strip for FIV, one for FeLV, and it was the FIV strip that was showing up positive (and faint at that). We still had to wait for the IDEXX test to come up, but the finders were already ecstatic. Considering how Banfield had initially flip-flopped on the diagnosis, we felt pretty confident that this was a case of “mistaken identity” (to put it nicely anyway – personally I think a vet’s office should be able to read a SNAP test, but hey, maybe that’s just me). Sure enough, when the SNAP test came up, it showed the same thing – FIV+, FeLV negative. I even pulled up the package insert, just to be absolutely sure we were reading it correctly (it’s really not that hard). So with two tests both saying the same thing (and one previous test that probably actually said the same thing), we called it – Bowie has FIV, NOT FeLV!

Bowie SNAP and Witness tests 2-19-16

The finders were fairly knowledgeable about cats and after discussing FIV and what that meant for Bowie (hint: not a big deal, and he can live just fine with other negative cats), they decided to take him home and keep him. Since Calvin’s Paws had already tested him, we offered to continue his care and handle his neutering, retest him again at that time, and then the finders could just pay our adoption fee to help cover the costs of care. They happily agreed, and by the next day I got an email saying that Bowie was already becoming friends with his new kitty housemate, who’s about the same age as him.

THIS is why I am such a freak about testing. THIS is why I am so adamant that ONE test on ONE day does not a diagnosis make. Aside from the fact that human error is always a factor to consider (because really, you can’t take the time to double check which spot is which?), all tests have a known false positive rate, and so any positive test should ALWAYS be repeated no matter what. Here is what Calvin’s Paws does any time a cat tests positive:

  1. Stop and repeat the test immediately. (Swearing while repeating the test is acceptable, especially if you’re the FeLV foster home and you know your husband is going to be quite displeased if you bring another one home.)
  2. If that test is positive, and the cat is an adult, make an appointment to send off an IFA test. If that’s positive, then the cat is considered positive. If the IFA is negative, then repeat the in-house tests and IFA test in a month or so.
  3. If the in house test is positive and the cat is a kitten, repeat the test in a month. IFA tests will usually be negative on kittens, so we don’t usually do them until the kitten has tested positive for several months, or until the kitten is about 6+ months old. If the kitten is with its mother and the mother is positive, separate the kitten from mom as soon as it is safely possible to minimize any potential exposure.
  4. TAKE A PICTURE of the test and attach it to a record of any positive test. Our database allows us to upload files to a cat’s profile, so that’s how we keep track, but you can do it however you want. If you’re at the vet and the vet comes in the room and says your cat has tested positive, ask to see the test. Then take a picture.

So at this point you might be thinking, “OK, I get that this is a crazy testing story, but really, how often does this really happen?” More often than you might think. Calvin’s Paws has taken in countless cats over the years with wonky testing stories. Consider Cremesicle for instance. He’s one of our current fosters who came to us in the summer of 2012 when his owners lost their home. His owners stated at the time that he was double positive, meaning he had both FIV and FeLV, and we took their word for it. He went to the foster that had our FeLV+ cats at the time, and there he stayed until I took him in December 2014. The first thing I did when I got the FeLV cats in the program was retest them – just for a new baseline (because I am all about data). To our great surprise, Cremesicle only tested positive for FIV. He was FeLV negative. He’s been living with FeLV+ cats for almost 4 years now, but now we have no idea if he actually has the virus or not. Sure his owners said he did, but that’s not what my tests say. We tested him again this year, and same results – FIV+ only. So now we’re in a bit of a tricky situation with him because we don’t have access to those initial testing records. Did he ever really test positive for FeLV? Did he initially test positive for both FIV and FeLV and later clear the FeLV from his system completely? Is the FeLV just suppressed by his immune system, hiding out deep in his bone marrow somewhere waiting to become active again if he ever becomes immunosuppressed? We literally have no idea. Frankly, this could be the case with any cat with an unknown history that tests negative – just because a cat tests negative doesn’t mean they don’t have FeLV (read more here), but with Cremesicle, because we were told he was positive, we have to treat him like a positive and disclose that potential risk to adopters. How would knowing what previous tests were done help us now? Well, in a perfect world, he would have had an IFA test done back when he was first diagnosed with his original owners. If that IFA test was positive, then he’s probably harboring the virus somewhere, and his immune system just has it under wraps. If that IFA test was negative, then there’s a pretty good chance that he cleared the virus completely, and is a FeLV negative (but immune) cat living with FeLV+ cats and struggling to be adopted because of it.

These are just two examples of the LUCKY ones. Imagine what it’s like in overcrowded, underfunded, public shelters. Many shelters still euthanize positive cats, based solely on one test. They simply can’t afford to do more testing, and one positive test is enough to condemn a cat in many places. Based on just my own personal experience with testing, I truly can’t even imagine how many healthy, loving cats that weren’t actually positive at all, get euthanized every year in shelters across the country. I bet the number is staggering.

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.


Pictures or it Didn’t Happen

My Christmas Wish

If you had one Christmas wish that was guaranteed to come true, what would it be? A million dollars? World peace? To be able to eat as many Christmas goodies as you want without gaining any weight?

For our cats, their one wish is to find their forever home. OK, so maybe that wish would be their second choice after unlimited catnip and cheese treats, but still. Yes, we fosters provide them with safe, loving homes, but it’s just not quite the same. There’s no joy quite like watching a longtime foster pick their new mom or dad – it can be almost a magical moment where the stars align and the heavens open up and you know that that match was meant to be. For some cats, this moment happens in a matter of days. For others, it takes years. But I know that for every cat, there is a special someone out there just waiting to take them home.

So my Christmas wish this year is for all of our “longtimer” cats to find a home in the coming year. Calvin’s Paws currently has over 50 cats that have been in the program for more than a year (see them all at, and more than half of those have been in the program longer than 2 years. I know, right? Wow. Sure, some of them have a reason – they’re shy, or they’re FeLV or FIV+ (although those of you who know me know how strongly I believe that this shouldn’t matter). But the majority of the cats on our list of “longtimers” have nothing “wrong” with them at all! They have simply been overlooked again and again and again.

Here’s where you come in: these cats need YOUR help. Yes, all of you – every single one. These cats need help finding their forever human. We know their perfect person is out there, they just haven’t found them yet. So please, help us spread the word about these wonderful cats – SHARE this post as much as you can; talk to anyone who will listen about how awesome cats are and why everyone should have one; hell, adopt one yourself! Donate to help us market our cats, foster and bring them out to adoption events, or join our mission to educate people about FIV and FeLV! Anything and everything that you can do helps.

Let’s get to work finding all of these cats homes!

To see all of our longtimers, please follow this link to our “Longtime Rescues” webpage! Then SHARE SHARE SHARE!

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.


My Christmas Wish

Just Say YES: Why FeLV Vaccines are Important to your Kitten’s Health

A few weeks ago, I wrote about FIV vaccines and why you should never, EVER give them to your cat. But let’s get one thing clear – I love vaccines. Vaccines are awesome. They’re an integral part of public heath (including pet health!), and your cats need them. The FIV vaccine is a special case in which the negative effects of vaccination outweigh the potential benefits.

With that being said, I want to talk about another non-core vaccine; one that you should ABSOLUTELY get for your kitten: the Feline Leukemia vaccine. (*Note: If you were thinking that FIV and FeLV are the same thing or you’re confused about the difference, read our blog post about the two diseases.)

Feline Leukemia is a potentially deadly disease that affects cats. Kittens are the most susceptible to becoming infected, and so they are the ones for whom the vaccine is most important. The American Association of Feline Practitioners (AAFP) recommends that all kittens be vaccinated for FeLV, although it is not considered a “core” vaccine for all cats.

It is most important if your cat is allowed outdoors. Although the prevalence of FeLV has declined (thanks to testing/isolation and vaccination programs), FeLV is still present throughout the United States, and your cat is at risk any time they go outside and have contact with another cat.

My kitten will be indoor-only, so why should I bother?

That’s fantastic! All cats should be indoor-only. But sometimes things happen, and your indoor kitten may slip outside for a jaunt around the neighborhood, where he could be exposed to various diseases including FeLV. He could get lost, he could get in a fight, and before you know it, you have a cat that is FeLV positive.

Why does Calvin’s Paws vaccinate all incoming cats for FeLV?

In the spring of 2015, the Calvin’s Paws Board of Directors made the decision to make FeLV vaccinations a part of the routine care that all new cats receive. We chose to do this for a number of reasons:

  1. Vaccination is a key part of any effort to eradicate any disease. Imagine if no one had to worry about FeLV anymore! That is the ultimate goal.
  2. The AAFP recommends the vaccination of all kittens, as well as adult cats that are kept in group-housing situations with other unrelated cats (as is often the case in foster homes).
  3. While we require our adopters to keep our cats indoor-only, the reality of the situation is that not everyone will comply. By vaccinating our cats, we are ensuring that they have minimal risk of developing the disease should they ever be exposed.

But all of your cats are tested for FeLV and FIV before they integrate with other animals in the program – so what’s the point of vaccinating if everyone is negative?

This is where things get interesting. FeLV is a sneaky disease, and in my experience, no case is “typical.” Recent research has shown that around 10% of cats that test negative on the standard in-house tests for FeLV actually do have the virus – it’s just extremely well-contained and suppressed by their immune system. FeLV is a retrovirus, and its modus operandi is to integrate into the DNA of its host. Once this happens, the immune system can’t get rid of it, even if it clears all of the active virus from its system. These cats are not shedding the virus and so are not contagious, and it’s unlikely that they’ll develop any FeLV-associated diseases. This is called a regressive infection. However, there’s a chance that if the cat later becomes immunosuppressed that the FeLV virus could become active again, and the cat would suddenly start testing positive and potentially develop FeLV-related diseases. As of now, it’s unclear how often this happens, or how significant it is. Because these cats test negative on the in-house tests that vets and rescues routinely use, there is no way for us to know if a cat has a regressive infection or if they are truly completely negative. Therefore, since many of our cats live in foster homes with other cats, the safest course of action is to vaccinate all of our cats. That way, if anyone later develops an active FeLV infection, the others in the household are protected.

Why doesn’t everyone already vaccinate their cats for FeLV?

One reason is that it’s not considered a “core” vaccine, so not all vets routinely recommend it – it just depends on the vet and the cat’s lifestyle.

FeLV vaccines are often criticized for not being 100% effective. However, some brands are better than others (Whole Inactivated vaccines are most effective, while recombinant vaccines are almost useless), and an adult, vaccinated cat has an extremely low risk of contracting FeLV upon exposure to the virus.

There has also been concern about vaccine-associated sarcomas developing after FeLV vaccination. A sarcoma is an extremely invasive type of cancer that can be difficult to treat. When FeLV vaccinations first started becoming common, vets noticed that the rate of sarcomas increased, and everyone panicked. Research has since shown that while there is a link between ALL vaccines (not just FeLV) and sarcomas, the incidence of a sarcoma developing at a vaccine site is roughly 1 in 10,000 cats. Considering that the prevalence of FeLV is roughly 2 in 100 cats (2.3% in a study done on the prevalence of FeLV in North America conducted in 2006), I’d rather take my chances with a sarcoma developing than my cat contracting FeLV, which can cause various cancers anyway. Besides, the rabies vaccine (which is required by law in North Carolina) has just as much risk as causing a vaccine sarcoma as the FeLV vaccine, but it has to be done. The benefit outweighs the risk.

The bottom line:

The FeLV vaccine is an important vaccine, especially for kittens. If we’re ever going to eradicate this deadly virus, vaccination is a key step. Be a part of the movement: vaccinate your kittens and keep all of your cats indoors.


From the AAFP Retroviral Management Guidelines: (

  • FeLV Vaccinations: The decision to vaccinate an individual cat against FeLV should be based on the cat’s risk of exposure. Cats that live in a FeLV-negative, indoor environment are at minimal risk. FeLV vaccination is recommended for:
    • all kittens because the lifestyles of kittens frequently change after acquisition and they may subsequently become at risk for FeLV exposure
    • cats that go outdoors
    • cats that have direct contact with cats of unknown status or in high turnover situations such as foster homes or other group housing
    • cats that live with FeLV-positive cats

From the 2013 AAFP Vaccination Advisory Panel Report: (

  • The Advisory Panel recommends that all cats under 1 year of age be vaccinated against FeLV and receive a booster vaccination 1 year later. After 1 year of age, the need for subsequent vaccination is determined by risk factors that the individual is exposed to.
  • Recommendations for Shelters – Feline leukemia (FeLV):
    • Administer a single dose of vaccine at the time of intake if group-housed. If group (rather than individual) housing for kittens is used, vaccinate as early as 8 weeks of age.
    • Revaccinate once, 3–4 weeks following administration of the initial vaccine.
    • Unlike group-housed cats, risk of FeLV transmission is very low for individually housed cats. FeLV vaccination is recommended for cats in long-term shelters or in group-housing of unrelated cats. Vaccination is not a substitute for testing and segregation of infected cats

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.

Just Say YES: Why FeLV Vaccines are Important to your Kitten’s Health

Feline Leukemia Testing: Clyde’s Story

A discussion of FeLV testing protocol.

In August 2015, Calvin’s Paws received a request for help for a cat that was positive for Feline Leukemia. The couple that found him owned a barn, and had spayed and neutered a number of cats that had found their way on to their property over the years, but when this cat was neutered, he tested positive for FeLV. The only place they had to keep him separate from their other outdoor cats was a cage in their garage, so I contacted them and asked what kind of testing had been done to try and determine if the cat was truly positive or if he needed to be retested. I was assured that their vet had sent off blood to a lab and that the lab had confirmed that he was FeLV+, but the finders couldn’t remember the name of the tests that were done. I assumed that it was an IFA test, and agreed to take the cat with the understanding that I would be able to get the records from their vet and figure out what kind of tests were done (because if you haven’t figured it out by now, I’m a little obsessive about testing).

The finders brought the cat to me – a STUNNING Chocolate Point Siamese boy named Clyde. I hoped that since he was so beautiful, he would draw people’s attention, and at least give me an opportunity to educate people about FeLV. He was scared at first, but we got him settled in to our FeLV+ foster room, and the finder left.

Clyde Clyde

Since I had some of his medical records, I decided to take a look and see what needed to be done with him (I knew he had been neutered, tested, and had his rabies vaccine, but nothing else). As soon as I looked at his records, I knew I needed to retest him right away before leaving him in my FeLV room. The vet’s office had performed an IDEXX Triple Test, which tests for FIV, FeLV, and Heartworms, and is notorious for having a high false positive rate. Even if it wasn’t a false positive at the time, it had been about 4 weeks since his initial test, so it was time for him to be retested again anyway. Being the medical coordinator for Calvin’s Paws, I had a couple different kinds of test kits on hand, and I immediately retested him using the IDEXX Combo Test (which only tests for FIV and FeLV) and the new Zoetis Witness FIV/FeLV test. I have to say – those 10 minutes waiting for the tests to finish running were some of the longest minutes ever (probably because I stood and watched them run…), but at the end of 10 minutes, the results agreed: Clyde was now NEGATIVE on both tests!

Clyde tests negative

I separated Clyde from my other FeLV+ cats, not wanting to potentially expose him to the virus if he wasn’t actually infected. The next day, I called the vet that had done his original tests, and talked about his case. The vet told me that she had run two tests – a Triple Test on whole blood, and another test on serum. When the results disagreed (the triple test was positive, but the serum test was negative), she sent a sample off to IDEXX’s lab. The vet wasn’t sure what kind of tests had been done at the lab – she only knew that the lab had tested the samples and told her that he was “definitely positive.” She promised to get the records from IDEXX and fax them to me, but I could guess what they would say. IDEXX has a habit of telling vets that if a cat is positive on one of their tests, then the cat is persistently infected and would remain positive (which is simply not true).

Sure enough, when I got the IDEXX records, they showed that the lab had simply re-run the exact same tests that the vet had performed in her office. The results agreed this time, and so the lab said he was positive and the vet took their word for it, and no further testing was done.

I immediately made an appointment with our vet, who drew blood and sent it off for an IFA test. When the IFA came back, it confirmed what our tests had already told us – that Clyde was now negative for FeLV! By this time, being the stunning Siamese boy that he is, he already had an adopter lined up, and was adopted a week later.

Clyde’s story is not an uncommon one. We’ve had a number of cats over the years that initially test positive for FeLV, only to test negative within a month or two. This is why Calvin’s Paws now has a rather detailed testing protocol: every cat that comes to us is tested individually, any cat that tests positive for FeLV has blood sent off for an IFA test to confirm infection, and if the IFA is negative (which happens a lot actually!) the cat is retested a month later. Usually within two months, the results of the tests will agree, and you can confirm if the cat is positive or negative. Side note – we do have a cat in our program, Ice Dream, who has been with us for about 8 years and who has consistently tests positive on in house tests, but negative on the IFA test; but she’s the exception rather than the rule.

So why might a cat test positive on one test and not another? Well, there are a few reasons.

  1. The first test results were a false positive. Calvin’s Paws always runs a second test if any cat comes up positive, just to rule out test error.
  2. The stage of infection affects test results. If a cat is in the first stage of infection, before the virus has infected the bone marrow, it may test positive on the in-house tests but negative on the IFA test. It is at this point that a cat has a chance of fighting off the virus and clearing it, and the cat may later test negative. In cases like this, where the in-house test is positive and the IFA test is negative, the cat must be retested at least one month later to determine its true infection status. After a month, the results should agree – either both types of tests will be negative or both will be positive. *Note: Emerging research has suggested that cats may not actually be able to clear the virus 100%, they may just suppress it and contain it so that it’s not causing disease and not showing up on either the in-house tests or the IFA test. FeLV is a retrovirus, and it integrates itself into the DNA of the host organism. Once that happens, it can’t be cleared, just suppressed and contained. The only way to detect these cases is by a PCR test, which amplifies any FeLV DNA in the sample. It has been found that around 10% of cats that test negative on all other tests will test positive for FeLV proviral DNA on a PCR test. However, the significance of this isn’t yet known. While it’s theoretically possible for the cat to later develop an active FeLV infection if they become immunosuppressed, it’s not known how often this happens in these cases. Regardless, these cats are not shedding the virus and so are not contagious.

But wait, why don’t vets know proper testing protocol?

The fact is, the rate of FeLV infection has been greatly reduced over the last 30 years, and many vets don’t have a lot of experience with cats testing positive. Combine this with the fact that the maker of the tests likes to tell vets that their tests are the end-all-be-all of testing, and you end up with cats that are wrongly diagnosed with FeLV.

So what? Why does it matter?

Knowing a cat’s true infection status is so important for so many reasons. First, many shelters immediately euthanize any cat testing FeLV+ (based on one test on one day). Even a number of vets still recommend euthanasia to owners of cats that test positive! Clyde is lucky – lucky that he didn’t end up at a shelter, and lucky that his finders cared enough about him to try and find him a safe place to live out his life.

Even if a cat testing FeLV+ is lucky enough not to be immediately euthanized, they’re hard to adopt out. Many rescues do not accept FeLV+ cats into their program, both because of quarantine issues and the fact that FeLV+ cats are only rarely adopted. Many people don’t want to adopt a “sick” cat (more on why FeLV+ cats aren’t “sick” to come), either because they don’t want to risk any extra vet expenses or because they don’t want to get attached to a cat only to have it die after a year. Not all people get to see what I see – that the FeLV+ cats are some of the absolute sweetest, gentlest cats you’ll ever meet. They are so loving, and so grateful to be safe and cared for. Yes, they can get sick and die, and when that happens it just about kills you, but that is true for any other cat. Yes, they might have a shortened lifespan, but they might still live for years. Look at our girl Ice Dream – 10 years old and one of the happiest cats I’ve ever met! Mikael – DOUBLE positive (he has FIV and FeLV) and strong as an ox at 4 years old! I for one won’t live my life based on “maybes” and “what ifs” – these cats are amazing and they all deserve a loving forever home just as much as any other cat.

So spread the word – FeLV+ cats are totally awesome, but be sure to test and retest before slapping the FeLV diagnosis on a cat!

Clyde adopted 3 Clyde adopted 2 clyde adopted Clyde in his new home


Diagnosis of feline systemic viral infections

ABCD guidelines on Feline Leukaemia Virus

Feline leukemia virus and feline immunodeficiency virus in Canada: Recommendations for testing and management

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.

Feline Leukemia Testing: Clyde’s Story

FIV Vaccines – Just Say NO!

Your vet offers to vaccinate your cat for FIV. You think “well, sure, why not? Vaccines are great!” NO! Your cat should NEVER be vaccinated for FIV!

First, let me make myself clear – I love vaccines. Vaccines are wonderful things that prevent a number of very serious illnesses, and they are essential in eradicating deadly diseases. However, there are several excellent reasons why your cat should never receive the FIV vaccine (and the AAFP – American Association of Feline Practitioners – agrees):

1. Current tests for FIV cannot distinguish between a cat vaccinated for FIV and one infected with FIV. Once vaccinated, your cat will test positive for FIV for the rest of their lives.

2. We’re not sure exactly how effective the FIV vaccine is anyway. The manufacturer claims it’s abut 80% effective, but other studies have found it’s only about 50% effective at preventing FIV infection.

3. Indoor cats that have been spayed or neutered have almost no chance of contracting FIV anyway. FIV is most commonly spread through very deep bite wounds (like the kind seen between unneutered stray male cats).

OK, that’s all well and good, but so what? My vet and I would know that my cat was vaccinated for FIV. What’s the worst that could happen?

Imagine if your cat slipped out the door and got lost. She’s picked up and taken to the local county shelter, where she tests positive for FIV. Ideally, she is reunited with you, but realistically, most owners are never found. If she’s lucky, a rescue group like Calvin’s Paws will be able to take her in and put her up for adoption. Since we wouldn’t know her history, we would have to list her as FIV positive, and it would likely take a long time to get her adopted. If she’s unlucky, she would be euthanized at the shelter upon testing positive. This is the unfortunate fate that awaits most FIV+ cats that find themselves at a shelter.

The possible consequences of vaccinating your cat against FIV far outweighs the actual risk of your cat contracting and becoming ill with FIV. If a test that can differentiate between an FIV-infected cat and an FIV-vaccinated cat ever becomes available, then maybe the FIV vaccination recommendation would change. Until then, JUST SAY NO!

Click here to read the 2013 AAFP Vaccination Guidelines:

Mikael is proof that you can  live a happy, active life with FIV
   Mikael is proof that you can live a happy, active life with FIV
Madre has FIV and is living a very happy, very active life
Madre has FIV and is living a very happy, very active life

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.

FIV Vaccines – Just Say NO!

Testing for FIV and FeLV – What the Tests Can and Cannot Tell Us

Why testing is not the end-all-be-all of retrovirus management in cats.

by Brittany Roth, Calvin’s Paws Medical Care Coordinator and FIV/Felv Advisor

It seems simple enough – you go to the vet with your new furry friend, and the vet recommends testing her for the two common retroviruses in cats – FIV and FeLV (for the difference between the two viruses and more information, read our previous blog post here). You get the test results back, and they’re either positive or negative, and that’s that, right? Well, not really.

Why not?

A positive test result may indicate that your cat has one of the two viruses…but it might not. How can this be? There are two main factors that play into this: the age of the cat or kitten and the virus that they’re testing positive for.


As we explained in our previous blog post, My Kitten has FIV, any kitten younger than 6 months testing positive for FIV most likely does NOT actually have the virus. The test for FIV looks for antibodies to the virus, not the actual virus itself. Kittens get antibodies from their mother while they are nursing, so if the mom has antibodies to FIV, she can pass those on to the kittens. Once the maternal antibodies clear out of the kitten’s system, the kitten will test negative.

The test for FeLV looks for an antigen (protein on the surface of the virus) of FeLV. A kitten testing positive for FeLV is a little trickier, but still not a sure thing. Yes, mothers can pass the virus on to their kittens in the womb or after birth, but just because a kitten gets a few virus particles in their system does not mean it will definitely become persistently infected. Kittens born to positive mothers should be separated from mom as soon as safely possible (6 weeks or so) and retested at 3-6 months of age. We have had several cases (including one just this year!) where kittens testing faint FeLV+ later cleared it from their system and tested negative within about 2 months.

FIV+ versus FeLV+

Adults testing positive are a somewhat different story, depending on which virus they’re testing positive for. Adults testing positive for FIV are usually actually infected, but a second test should ALWAYS be performed to rule out test error. If a cat tests positive with Calvin’s Paws, we always immediately do a second test, and then retest the cat in a month. If all tests agree that the cat is positive, then the cat is probably positive. But here’s the kicker – as mentioned above, tests for FIV look for antibodies to the virus, and current tests can’t tell the difference between an infected cat and a cat that was vaccinated for FIV! So even if all tests agree that your adult cat is positive for FIV, there is still no way to determine if he actually has the virus itself.

Adult Cats

Adults testing positive for FeLV simply cannot be diagnosed with FeLV based on one test. FeLV is a very complex virus and is still not well understood. When a cat is exposed to FeLV, there are 3 possible outcomes:

  1. Some cats will not be infected due to inadequate exposure and a good immune response. These cats may initially test positive for FeLV after exposure, but will test negative once they clear the virus from their system.
  2. Some cats will develop a latent or regressive infection; these cats will not be able to destroy all of the virus, but will be able to hold it in check. The virus integrates into the cat’s own DNA but is not active. These cats show no signs of infection and usually do not shed virus in their saliva or other body secretions. However, the infection can later become active again, especially if the cat becomes stressed or immunocompromised. These cats may or may not ever test positive, depending on when they are tested.
  3. Some cats will become persistently infected; these cats will not develop an adequate immune response and will remain permanently infected with FeLV. This is called a progressive infection. These cats will shed large amounts of virus in their saliva and often develop FeLV-associated diseases within a few years. These cats should always test positive.

If a cat is tested only once for FeLV and comes up positive, it doesn’t tell you much. One positive test does not tell you which of the 3 outcomes above that the cat will have – they might be able to clear the virus completely, they might suppress it and never have symptoms, or yes, they might actually be persistently infected. To actually diagnose a cat with FeLV, you must do more testing. When an adult cat tests FeLV+ in Calvin’s Paws, we immediately repeat the in-house test to rule out test error. If that is also positive, we then take blood and send it off for an IFA lab test – this gives us a better picture of the stage of the disease. If the IFA test is also positive, it means that outcome #1, clearing the virus completely, is extremely unlikely, and we can officially diagnose the cat with FeLV. If the IFA test is negative, it means that the cat is still in the stage of infection where they might be able to fight the virus off completely. In this case, we isolate the cat and retest them in one month. Theoretically, you keep retesting until the test results agree, but it is possible for a cat to have an atypical infection and consistently have discordant results on the in-house test and IFA test. This is the case with one of our FeLV cats, Ice Dream, who has been with us since 2007 and STILL tests positive on the in-house test and negative on the IFA test.


But if my cat is negative and has ALWAYS been negative, then he’s negative, right?

Not necessarily. Remember outcome #2, where cats can have a latent or regressive infection? If cats have a regressive infection, their immune system has cleared all traces of the virus from the blood, but the virus’ DNA has integrated into the cat’s own DNA, which the immune system can’t do anything about. These cats will test negative on the in-house tests AND the IFA lab test! The only way to identify them is through a PCR test, which looks for FeLV DNA and magnifies any fragments it finds until it’s at a detectable level. Because PCR technology is relatively new, there is still a lot of ongoing research on what the results of it mean in terms of the health of a cat. We do know that regressive infections can become active again if the cat is stressed or immunosuppressed, but there is very little data on how often this happens. The most current research has found that somewhere between 5% and 10% of cats that test negative for FeLV actually test positive on a PCR test, indicating a possible regressive infection.

Aside from all of this, tests cannot detect infections immediately after exposure. If a cat was recently exposed to either virus (less than a month or so before testing), they may test negative simply because they were tested too soon after exposure. Then when you take into account the fact that the tests themselves do have a known error rate for both false positives and false negatives…well, you can see why interpreting tests gets tricky.

In conclusion, a positive test result does not always mean the cat has the virus, and a negative test result does not always mean the cat does not have the virus. This doesn’t mean that testing isn’t worth doing – it just means that testing should be a starting point, not the one and only step of retrovirus management. Unfortunately, many shelters (and even vets!) treat each individual test as undeniable fact, and the results of that test are literally life-or-death.

Calvin’s Paws is a 501(c)(3) rescue. We work through a network of foster homes throughout the Triangle area to save homeless cats and dogs. We are a dedicated group of volunteers with common goals: rescuing animals (both positives and non-infected felines), finding the best fitting homes for each animal, and educating the public on animal health and responsible pet ownership.

Testing for FIV and FeLV – What the Tests Can and Cannot Tell Us