This page: How safe is it to keep an FIV cat together with non-FIV cats? A natural concern for an owner, what are the real risks? We look at the evidence.

FIV - Mixed households

FIV cats living together with uninfected cats.

One of the most common questions we are asked, is from people who find their cat has tested positive for FIV. They want to know what the risk is to their other cat(s) if the FIV cat has contact with them.

Many rescue organisations are badly informed about the subject, and often give poor advice, as, sadly, do many vets.

We wish to allay fears, and point out that, without fighting, there is very little danger of the virus being transmitted; although theoretically possible, in practice it just does not happen other than in extreme situations.

No one can give you cast iron guarantees, but there is absolutely no real evidence of casual (non-fighting) transmission of FIV. We have been involved with FIV cats for almost twenty years now, and we have yet to find a single example of proven casual transmission in a normal household - and we have looked hard!

There are always a few cases where it is claimed to have happened, but in the few examples we have found, the fact is the virus was transmitted without any explanation; often in a stressful high density environment. In a few cases, it was found that the owners had never actually had the cat tested negative, they just assumed it was negative before they discovered otherwise.

Even the official professional publications, when they refer to casual transmission, only have one reference on which they rely; a single study carried out here in the UK twenty years ago. We have looked carefully at that study and, in fact, although transmission was recorded, the means of transmission was not established. Yet that is the sole reference these papers quote in support of casual transmission. (read more about our look at that study)

The only proven danger of transmission is via a bite, where the virus in the saliva is effectively injected directly into contact with the recipient's blood, thus infecting that cat.

The rare report of transmission without observed fighting has, in our view, more to do with the unobserved bite than any other mode of transmission. However well cats get on, there will always be an odd individual clash of personalities, and that is where we think the rare occurrence takes place - through a short 'spat' with a bite that transmits but was not observed, and never identified.

Over the last twenty years, more and more FIV cats have been living in mixed households. If it were a problem, one would expect there to be increasing reports of casual transmission, but there simply are none!

Of course, transmission can occur if the FIV cat were to bite a non-FIV cat. So the cat's personality is most important. Most cats, once neutered and provided with regular food, lose the need to fight for food and territory - this is the basis of all the rescued cats now in homes living with other cats and no fighting taking place. As long as the introductions are slow and thorough, all will be well. It will become obvious quite quickly if there is any real personality problem between individual cats, only then would you need to think further.

Having said all that - remember that, with a well cared-for cat, having FIV is not really a problem. The FIV cats who have health problems are those who are not cared for and are exposed to stress, poor diet and little veterinary care - that won't happen with well cared for cats, so all would be well even if your worst nightmare were to take place!

As what we tell people is backed up by our own experience, a few years ago we collected real experiences from other households that have one or more FIV cats living together with non-FIVs - their experiences are shown below - this should help others to make their own decisions based on real experience, rather than ill-informed opinion.

More recently, the '1000 FIV cats project' has also collected information from owners of FIV cats around the world - well over 60% of which have FIV positive cats living with uninfected cats with, to date, not a single report of transmission of the virus within their household. (Use the main menu to see the project results)

The following are the earlier reports sent to us from various parts of the world - all have first-hand experience of mixing FIV positives with negatives:

(either scroll down to read the stories, or use the menu below to jump to individual stories)


Examples of mixed households:

Positive and negative live together for 8 years - no transmission -
From Kathleen - USA - North Carolina

Positive lives with 6 negatives for 2.5 years (and counting) - no transmission -
From Daniela - USA - upstate NY

Positive (Thomas) with negative (Eddie) for 5 years - no transmission -
From Veronica - Oregon USA

One positive living with six negatives -
From CAM - Florida, USA

One Positive living with 5 negatives -
From Joan - USA, northwest of Boston, MA

Siblings, one positive one negative, together 2 years - no transmission -
From Samantha - Co Cork, Ireland

Three feral kittens, one positive, two negative -
Candy, Florida, USA

Two positives, one negative -
From Beth, Midlands, UK

Two positives, three negative - 6 years -
From Denise, UK


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From Kathleen - USA - North Carolina
Positive and negative live together for 8 years - no transmission

I have Leon, a 12 year old FIV positive male cat, and his best friend and "brother" Harrison, is a non-FIV 8 year old male.

Leon (FIV) was an only cat about 4 years old when I rescued Harrison as a kitten.

Leon had been around many other FIV positive cats who I fostered temporarily for a local rescue, and I knew he was very friendly and got along great with other cats. It was because of his gentle nature that I knew (as well as my Vet advised) that it would be ok to introduce them.

They actually got along very well, and to this day, share a litter box, water bowl, and bathe each other and play together (including gentle play-biting).

In addition, I also fostered another cat for about 4 months (who ended up going to a new home) and tested negative after living with Leon.

I also had a roommate who had 2 negative cats who lived in the same house with Leon and Harrison for almost 2 years, and both of them continue to test negative.

I test Harrison every year or 2, and he has always been negative.

If FIV was transmitted by casual contact, Harrison would have been positive after living with Leon for 8 years!
- Kathleen
USA - North Carolina
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From Daniela - in the US - upstate NY

Positive lives with 6 negatives for 2.5 years (and counting) - no transmission

I have one FIV+ cat (Leo) and 6 negative cats. They have lived together for about 2.5 years now and there has been no transference.

My cats get along very well - I don't separate them in any way - they eat and drink from the same bowl, sleep in the same beds, play together.

I don't really have an experience with FIV+ and FIV- because I don't notice any difference. Ask anyone who comes into my house and they can't tell you which one is FIV+.

I don't see a need to retest the negative cats, but I have them tested for roundworms every year or so and that test also tests for FIV and FELV so I would be aware if their status were to change. So far no changes and I don't anticipate any.

If any of them did change to FIV+ nothing would change besides keeping a closer eye on their health. I would definitely consider adopting another FIV+ cat.

Last year I took in a feral cat and let her out of the trap into a room instead of a cage - which makes taming a lot harder. I haven't been able to catch her again to get her to the vet to be neutered so she went into heat and she seems intent on having my FIV+ cat, Leo, father her next batch of kittens. All the other cats in my house are neutered so it isn't going to happen

The two of them will often lie together and groom each other and sleep nestled together. Leo also has a best friend, Willis, that he frequently plays with and cuddles with. He is also a huge human lover - if you were to come to my house Leo would greet you and then make a point of jumping on your lap and rubbing his head on your face. A few people have threatened to take Leo home with them! :-)

I know in the future that he may be more likely to have health issues, but since I just had a "normal" cat die of kidney issues this is not something I am all that worried about - sickness can come to all animals - all it means is keep a closer eye on him if he does get sick to make sure it doesn't progress too much.


in the US - upstate NY
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From Veronica - Portland, Oregon USA

Positive (Thomas) with negative (Eddie) for 5 years - no transmission

When I took in Eddie, FIV-, in 1995, he decided that Thomas, FIV+, was his best buddy.

At the time I had one other FIV- cat who had lived with Thomas since 1993, but she hated him (and all other cats).

All the cats shared food, water, litter boxes, sleeping sots, etc., but Eddie could often be found curled up with Thomas. Thomas did not seem especially thrilled with this, but tolerated it.

I often rushed out to break up their apparent fights (howling, leaping on each other, rolling around, "head locks"), until one day my house call vet was at my house and his assistant/wife who bred cats said it was not fighting just REALLY rough play.

This roughhousing may have been because Eddie was much younger than Thomas (about 2 years compared to Thomas's 11 or so). In any event, Thomas died in the fall of 2000, but we had Eddie until last spring (2009) and Eddie never developed FIV.

The cat who hated all others died in late 2006 and she, also, did not develop FIV.

During that time, we had adopted another FIV+ cat, although Eddie was not as fond of Julius as he was of Thomas, all the cats lived together and shared everything.

Eddie was tested fairly often after my original vet retired - pretty much every time he saw the vet, so I would say from 2003 or so on. Then when Eddie and Stubbs (the female) became sick (both had IBD, though Eddie also had cancer) they were tested repeatedly. They were, and remained, negative.

Portland, Oregon USA
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From CAM - Florida, USA

One positive living with six negatives

I have one FIV+ female cat and 6 non-FIV cats (1 female, 5 males)...All are neutered, and all are indoors-only cats. They have plenty of room in our 3-bedroom house, and lots of windows to look out. None of them seem to be interested in going outside, possibly because they are all shelter/rescue cats who were dumped by owners and left to fend for themselves.

The FIV+ girl was in bad shape when she was brought to me, she was horribly thin, had a bad fever, and a bad URI. All she wanted to do was hide and sleep, the poor girl. I had 2 boy kittens at the time when I brought her home. I didn't even know she was FIV+ until I took her to the vet to get her checked and get treatment for her URI. Our vet did the 3-in-1 test that tests for FIV/FELV/heartworms, and only the FIV was positive. She had the wonderful brochure from Cornell regarding FIV, and said that my new girl should be able to live a long, healthy life. She was very good about answering my questions...I was a bit in shock since I didn't really know anything about FIV, but I came right home and researched it to find out as much about it as possible. This was just back in September 2008.

I'm very fortunate that I am able to work from home, so I get to spend lots of time with my kitties and see how they interact with one another. My FIV+ girl is not at all aggressive. She's very motherly toward the other kitties, a very gentle and affectionate girl. They all play together, eat from the same bowls, drink from the same water bowls, and use the same litterboxes. Everyone is healthy, including the FIV+ girl. She's approximately 2 - 3 years old now. We had a kitty virus go through the group here, probably carried in by me or one of my friends from one of the outdoor cats, and my FIV+ girl didn't have any problem with it. She barely even got the sniffles while some of the FIV-negative kitties were sneezing and congested for a couple weeks.

When I added kitties after the FIV+ one, I did put them in a "quarantine" room apart from the others for about a month, in addition to having them checked by our vet. That might have been an overly-cautious thing to do, but I wanted to minimize the risk of them bringing any infection in that might cause another round of kitty colds. It also allowed them to get used to each other through the closed door prior to meeting, so I think the meetings probably went smoother than they would have if I had simply brought the new kitties in and let them loose.

I don't give my FIV+ girl any special supplements or anything. She does not seem to need any special care at this point, although I'm prepared for that, if it comes about later in her life. They all eat the same food, which is a mix of 3 different premium foods.

You would never know I have an FIV+ kitty if I didn't tell you which one she was...She looks and acts the same as the others. She doesn't look sick, act sick, or even get sick. She plays, eats, sleeps, enjoys catnip parties, just like the rest of the kitty gang ;) She has not had to have any more vet care than any of the others.

Mystery (FIV+) grooming Blackie (non-FIV) 2010

Florida, USA
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From Joan - in the USA, northwest of Boston, MA

One Positive living with 5 negatives

I presently have six cats, all indoor house cats. One is FIV+.

I hate to tell you how many cats I trapped only to find they were FIV+ and, per the vets I dealt with at those times, had to be put down. The last one to be euthanized just about broke my heart, and I vowed never to do this again. Good decision!

My next personal rescue turned out to be FIV+ also, but I brought him home to stay. I went into this situation not knowing how it would turn out, but fortunately all has been well.

Sarge (he has lots of stripes) turned out also to be a Maine Coon Cat and an utter wuss. He thinks twice before biting his kibble and is timid by nature. I understand now that a deep bite is necessary for transmission of the virus and I do not see this as likely. One of the other two male cats loves Sarge and the other, the Alpha cat, treats him like he treats all the others. No fights though.

I have had Sarge since I trapped him in November 2008. I have not retested any of my other cats as I see no evidence whatsoever of any serious fights or bites. One of my ferals who has been with me about six years, Baby, adores Sarge. Unfortunately this is unrequited adoration! However, no signs of fights, and Baby is only now beginning to let me touch him. I credit his closeness to Sarge for that gigantic step forward. I also have a one-eyed cat and another sweet feral girl who has been living under my bed for a year and a half! The other two are "normal." It's quite a household, and all of the cats are treasures.

Sarge in 2010

in the USA, northwest of Boston, MA, in Burlington
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From Samantha - Co Cork, Ireland

Siblings, one positive one negative, together 2 years - no transmission

I have two, 2 year old female cats, who are litter mates. Nahla is FIV+ since she was found at 6 weeks old so we are presuming that she got FIV from her mum. Senna has always tested negative.

We recently retested Senna and she remains negative. This is her 3rd negative test. Nahla has always tested positive including the PCR test to confirm the positive snap tests.

They both share beds, toys, litter, water, groom each other and have occasional fights but have never drawn blood. I do feed them separately just to be extra safe.

Senna on the left and Nahla (FIV) on the right

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Three feral kittens, one positive, two negative

Here at Catwork, we were contacted back in 2005 by Candy in Florida, USA. She had rescued three tiny kittens from a feral cat. One of the kittens tested positive for FIV (RJ - Rusty Junior), the other two (Pumpkin and Sunset) were negative.

After repeated tests over several months, the positive one (RJ) remained positive, but Candy decided to keep them together, and also introduced them to her existing cat (Puddytat).

Over the years Candy has kept in touch and kept us up to date on their progress; I copy some excerpts from her emails here:

(March 2006) "Our kitties and Puddytat are doing very well. I think you may find this interesting. A couple months ago Pumpkin (Punky), the runt of our litter had a very swollen eye. We took her to the vet, and she was diagnosed with an upper respiratory infection. The vet gave us medication for her and extra in case the other kittens started to show signs of getting sick. She also warned us that the symptoms may worsen over the next couple days even though she was getting medication. Sure enough her eye got worse and started draining/watering, she started to sneeze, got lethargic and appeared miserable. Then Sunset started to sneeze, so we started her on the medication too. We were closely watching RJ (FIV) and even gave him one dose of the medication just as a precaution as we feared this could become an issue for him. Even though all kittens are together all the time; playing, sleeping and eating out of the same bowls, RJ NEVER showed signs of anything! He stayed healthy during it all and so did Puddytat. They are all fine and quite healthy now.

(Nov 2006) RJ has really taken a liking to me and comes to me to get his back scratched. He just loves to be petted these days and can't seem to get enough--he will lay by me for as long as I will keep petting him. What a turn-about from the first 9 months we had him--it took long enough! Patience and persistence pays off!

(April 2007) Our brood is doing great! The kittens just turned two years old in the last week or so, to the best of our calculations. All are healthy and very affectionate. RJ (our FIV) is almost 16 pounds of muscle and the picture of health. He's still never been sick; not even the sniffles. The two non-FIV have had at least one bout with upper respiratory infections, but recovered quickly. Puddytat, our older cat (12 or 13 years old), loves, accepts and plays with the kittens. He is actually more playful now with the kittens than he has been since he was a kitten.

All the cats have been a real joy to us. We are so glad that we found you on the internet to answer our questions and respond to our fears/concerns regarding FIV. We could not imagine being without RJ. Thank you!

(Feb 2008) RJ (FIV) is awesome! His health has been perfect! He is always bright-eyed, happy and a real joy. He is such a love and has added so much happiness to our household. My husband and I are always commenting on how glad we are that we kept him and did not listen to those people who said he needed to be put to sleep or given to a household with no other cats. All 4 of our cats have been healthy (the other 3 have had a few upper respiratory infections; RJ has not been sick a day in his life).

(July 2008) I wanted to let you know that our oldest cat, Puddytat, who is about 15 years old was very sick a couple months ago. He was ill for about 3 weeks and our vet could not figure out what was wrong with him; he had a fever and was extremely lethargic and hiding in a dark closet. After many tests and medications, the vet suggested an FIV test just to rule it out since we do have one FIV+ cat. Puddytat's FIV test was negative! Bob, you were so right in everything you told me about FIV. All the cats share food and water bowls, sleep together, groom each other (Puddytat loves to lick RJ's face and ears) and the FIV has not spread to the others

(May 2010) I told you that I'd send you a picture of my FIV cat, RJ, and his siblings, so here it is (see below). All are extremely healthy. We also still have Puddytat, who is now 16 years old. He still rules the roost including our 2 Great Danes!

They are from left to right: RJ (male -FIV+), Pumpkin (female - the runt) and Sunset (female - the friendliest cat ever).

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From Beth - Midlands, UK

Two positives with one negative

I've got two FIV+ boys (Kane & Oliver), aged 5 and 8. I've just recently adopted a kitten (Summer) who is negative. At 16 weeks old she adores the boys, sharing their food, sleeping in their beds and playing with them. Being a kitten her play can get quite rough and there is some play biting, both on her part and the other two's. However, they're all happy and healthy so I don't worry to much about it.

I'm well aware that all three of them are just as likely to become ill from something that is non-FIV related. I've had both the boys for some years now and they've never had anything more serious than an upset tummy.

If Summer ever needs a blood test for something else I might ask them to test for FIV just to see, but I wouldn't go out of my way to test her. Because they're all indoor cats the way we treat her wouldn't change if her status changed anyway.

Left to right - Summer, Kane & Oliver

Midlands, UK
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From Denise - UK

2 FIVs with 3 uninfected - 6 years

I had 2 FIV boys (Jess 12 and Keats12) living with my other 3 uninfected cats 2 boys and a girl (Rosie 6, Tennison 6 and the senior of the group Byrone 18). Sadley last year I had to have Jess pts aged 12.

The 2 FIV cats have always been very laid back gentle boys, as are my other cats. All the cats have shared food bowls and water dish it's never been a problem.

Keats is FIV, he has a problem with his thyroid which is controled by a tablet each day, he had to have his ear removed about 6 months ago due to a problem with his ear canal. This week we went to the vets to get his medication for his thyroid and she was taken aback by just how well this FIV cat was doing.

I believe if you have gentle cats they can all live together happily, as all mine have. I knew when I took on Jess and Keats (both had lived as strays in their previous life) what I was taking on and it's been fine.

My other 3 non-FIV were retested about 4 months ago and are still clear.

Keats has been with us for over 6 years, adopted up as a stray. When I took him to be neutered they told me he was FIV but healthy; by then I knew he's adopted us so as far as my daughter and I were concerned he had a home so he was here to stay. The FIV has never been a problem


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