How cats become infected with feline coronavirus, the virus which causes FIP

Feline coronavirus (FCoV), which causes feline infectious peritonitis (FIP), is shed in the faeces. FCoV infection occurs when cats ingest (or inhale) the virus. FCoV is a very contagious virus and it only takes a tiny speck of cat litter dust from a litter tray previously used by an infected cat for the virus to spread.

FCoV is a moderately stable virus, lasting up to 7 weeks in the environment (so it is not as stable as parvovirus, which can survive for a year, but is a lot more stable than feline herpesvirus which survives only about 12 hours). FCoV is protected by cat faeces, by cat litter (unless the litter has anti-virus properties) and the by the stable environment inside a house or shelter. Outdoors, cat faeces is buried by the cat and is rapidly broken down in the soil. Cats do not seek out each others' faeces, as dogs do, so there is a good chance of the FCoV dying long before another cat is exposed to it. Of course, FCoV has evolved to deal with this problem and is incredibly infectious and is shed at a rate of billions of particles per gram (or ounce) of faeces.

In this animation we meet Augustus, a healthy FCoV infected cat, and see how when he uses a litter tray, his faeces contains billions of the highly infectious virus. Augustus will shed virus in his faeces for a few weeks or months, then will stop shedding the virus -- it is likely that nobody will ever know that he was infected. Enter Plato, an uninfected cat who has to share a litter tray with Augustus. Even if the tray has been de-clumped (i.e. cleaned) since Augustus used it, it will still contain enormous amounts of coronavirus. The virus gets onto Plato's paws as he covers his own toilet, and when he grooms himself, he licks virus off his paws and swallows it. We believe that the virus first infects the cells lining the small intestine (called the epithelial cells of the villi). Once a cat is infected with FCoV, a battle begins between his immune system and the virus: most cats win, eliminating the virus after a few weeks or months. However, an unfortunate 5 to 10% of infected cats go on to develop feline infectious peritonitis (FIP).

The best way to prevent FCoV infection is to allow your cat outdoors if it is safe to do so. If cats must be confined indoors, have at least one litter tray for every cat in the house -- preferably in lots of different rooms. It takes only a tiny speck of infected cat litter dust blown onto cat food for a cat to become infected with FCoV, so keep food and water bowls as far away from litter trays as possible. Covered or self-cleaning litter trays are probably best. In this animation there is an easily disinfected floor, and a dirt trapper mat placed near the litter tray, to capture microscopic particles of infected cat litter, but there were too few litter trays, so the cats had to share. One colleague of mine trained her cats to use their own litter trays placed in different rooms, preventing transmission of virus from a FCoV carrier cat to her uninfected cats. Some people have trained their cats to use human toilets.

Recent research at catvirus.com has shown that the type of cat litter you use will affect the transmission of FCoV between your cats. At present, we have found no litter which completely prevents FCoV transmission, but using a cat litter which tracks minimally, and which has some anti-virus properties, is a good idea. The worst litters for FCoV transmission are the wood pellets which turn into sawdust and track all over the house. Examples of litters which we are currently investigating are:

Cat Attract™ from Precious Cat Litter (www.preciouscat.com)
World's Best Cat Litter (www.mpmproducts.co.uk www.worldsbestcatlitter.com)
AK clumping (www.asmineral.com/products.asp)

Fewer than 10% of FCoV infected cats develop FIP. Happily most cats who become infected with FCoV only shed the virus for a few weeks or months, then their immune systems kick the virus out.

Acknowledgements
I thank the many people who help me in my research and my quest to eradicate FIP by donating samples from cats; money; their time and expertise (especially Melody Amundson of www.mariposacreations.net for generously donating her web design skills); the many translators who kindly disseminate information in other languages; Marleen of the Yahoo FIPCatSupport Group (http://pets.groups.yahoo.com/group/FIPCatSupport) and writer/broadcaster Steve Dale of Petworld (www.stevedalepetworld.com and www.chicagonow.stevedale) for support; and of course Dr François Bagaïni of www.vetocyte.fr for his brilliant animation skills.

Category:

Pets & Animals

Tags:

• Feline
• infectious
• peritonitis
• FIP
• coronavirus
• FCoV
• cat
• litter
• infection

[stephaniecatlover01]

Dr. Addie,

I also wanted you to read a website about a cat rescue person that says she has cured some FIP cats with a vitamin C regime.  I guess utube won't let me put the website address here but I can email it to you. I would like to know what you thought about this, she also gives contact info of her vet that used the vitamin C on her cats. I value your opinions and appreciate all the work you do to help sick cats. Thank you. kay1931@hotmail.com

[DrDianeDAddie]

@stephaniecatlover01 One has to be very careful with vitamin C in cats because prolonged use can predispose to bladder stones.

[stephaniecatlover01]

Dr Addie, I am really needing advice on how to cure chronic nasal inflamation that doesn't respond to clavamox and doxycycline. I am in cat rescue and some of my felv/fiv neg cats have this and I haven't found a way to help them! Usually they have no nasal discharge or sneezing. Over time their nasal airway seems to get smaller and smaller, some of them start trying to breathe thru their mouth to get more oxygen but it doesn't help much. If you have advice pls email me kay1931@hotmail.com

[DrDianeDAddie]

@stephaniecatlover01 I suspect you may be dealing with feline herpesvirus infection. Stephanie - are there too many cats in your rescue shelter? This is a frequent problem for people saving cats, especially during this financial crisis. A network of fosterers can be safer than a shelter in terms of infectious disease control. Avoid dry foods, and give raw meat daily or every other day: even a soup spoon a day will help keep their arginine blood levels up, and strengthen their immune systems.

[leavesontree3267]

Is a FCoV-positive cat, 4-5 years old, have a lower risk of developing FIP, in comparison to a kitten or a senior? Is there any place that has kittens or cats for adoption that are FCoV-free? Is there a kitty litter that can kill the virus so it won't spread? Is there a particular litter you suggest? Why do only some kittens who have feline coronavirus, who are stressed from adoption or neutering, the same as others, develop FIP, and others don't? Thank you.

[DrDianeDAddie]

@leavesontree3267 It would appear, from data of age distribution of FIP cases, that middle aged cats are less likely to develop FIP than kittens or the old. Prof. Niels Pedersen once said that it might be better to obtain cats and kittens from personal ads in newspapers than from a shelter - he was probably right, though it depends on the shelter.

[stephaniecatlover01]

I understand because of lack of time if you cannot answer these questions but I wanted to put them out there anyway thank you.

[stephaniecatlover01]

From your catvirus.com website - In summer of 2009, an exciting paper appeared by Prof. Al Legendre of Tennessee Veterinary School in the Journal of Feline Medicine and Surgery reporting cure of 3 cases of non-effusive FIP using Polyprenyl Immunostimulant from Sass & Sass. This paper is a hopeful pilot study and I look forward to a controlled clinical study. Unfortunately, Polyprenyl Immunostimulant does not work on effusive (wet) FIP cases.

Do you have any updated info on this research?

[stephaniecatlover01]

I think inbreeding is also causing many health problems in cats and is difficult to avoid. I believe cats from the street make up the majority of ones that enter shelters. They are usually from colonies made up of moms and dads that can breed with their offspring when they reach maturity. Even cats that aren't part of some formed colony can be related to other cats in the same area, distant cousins for example. Going to a breeder isn't a sure thing either many bad ones out there.

[stephaniecatlover01]

Yes, having enough foster homes can prevent health and behavior problems. I have found it pretty difficult to find responsible and reliable people to help out with fostering cats. I will keep what you said in mind about the vitamin C and FIP. Are you not able to suggest a medication to treat nasal inflamation? I have been told this by other vets they won't give out advice without seeing the cat and I can't afford to go from vet to vet. Just another hurdle to deal with being in rescue.

[stephaniecatlover01]

Dr Addie, thank you for your replies. One of my rescue cats had the worsening nasal inflamation while she was on the street and that is why I took her home. There is one other cat at her colony so in her case it doesn't seem to be from being around too many other cats. I have 9 other cats and they have a large living space. I keep their litter boxes ultra-clean because I believe cats coming in contact with other cat's feces is going to compromise their health in many ways.

[DrDianeDAddie]

@85lalala96 Yes indeed - World's Best Original litter tracks the least of the litters which I have examined. However, no litter totally prevents FCoV infection. Allowing cats to toilet outdoors - even in an enclosed pen - is safer than having them indoors, sharing a litter tray from a FCoV point of view. (Though outdoors of course they may face other dangers.)