FCoV prevention in kittens has come to be known as the "early weaning and isolation" technique, since essentially that is what you do. Kittens are protected from FCoV infection by antibodies they receive in their mother's milk, when these antibodies wane, the kittens become susceptible to FCoV infection and the attendant risk of FIP. Early weaning and isolation has enabled cat breeders to continue to breed from queens who are actively infected with FCoV and shedding virus.
In my first FCoV survey, we noticed that 50% of kittens who were allowed to mix with queens other than their mothers, and/or kittens from other litters, became infected with FCoV. Only one third of kittens who were kept only with their littermates and antibody positive mothers became infected, indicating that about one in 3 antibody positive cats was shedding FCoV at any one time. However, litters who had been weaned before 5-6 weeks and isolated completely from all other cats and kittens in their household were all negative - even when the reason for that early weaning and isolation was because their mother had died of FIP.
The steps for early weaning and isolating kittens are as follows:
1. Prepare the kitten room
FCoV can survive in the environment for up to 7 weeks, so it is important that the room(s) that the kittens will be born in and grow up in be as free from infection as possible. Make sure that all the cats, except the pregnant queen, stay out of this room for 1-2 weeks before the litter is expected. Vacuum to remove any possible particles of infected cat litter (microscopic, dust sized particles). Prepare clean utensils - litter tray, poop scoop, food bowls - by disinfecting with sodium hypochlorite (household bleach, e.g. Domestos and Milton) for at least 20 minutes, then thoroughly rinsing in water. Most disinfectants kill FCoV but bleach is the first choice because it kills FCoV and other viruses and is safe for cats, use at a dilution of 1:32 (which means that if you use one cupful of bleach, you would add 31 cupfuls of water to it).
Remember that queens have to be relaxed to give birth and rear kittens successfully: allow the expectant queen to get used to being in the kittening room: feed her there; pet her in the room. As humans, we tend to want to give the new litter nice, clean, newly washed bedding, but the smells of soap that are pleasing to us are not pleasing to a cat! Once you have cleaned materials for the queen's bed, sleep with them in your bed to get plenty of your scent onto them, rub them along the lips and chin of the queen to get her scent onto them. Naturally, it is important to try to avoid viral contamination if possible, so don't allow other cats to sit on the clean bedding. It is vital that the queen feel as secure as possible in her kittening room, as this will reduce the chances of her rejecting or cannibalising her kittens. It will also reduce her stress levels, which in turn will reduce her chances of developing FIP.
2. Practice barrier nursing to prevent the spread of FCoV to the kittens
As we saw above, in How to prevent FCoV transmission, FCoV is mainly shed in an infected cat's faeces and is then eaten or inhaled by a susceptible cat or kitten. FCoV is a very infectious virus. Thus, the faeces of infected cats are the major source of infection and FCoV can be inadvertently spread from a cats' litter trays and poop scoops, and on our feet, clothes or hands.
The practise of "barrier nursing" will be familiar to human and veterinary nurses, doctors and veterinary surgeons and many others whose work involves restricting the transfer of invisible contaminants. The first rule is to deal first with the least infected area of our house or cattery (in our case, our kitten rooms) and gradually move up to the most infected area (perhaps our known FCoV carrier cats, or a cat sick with FIP, last). It is a useful idea to establish a routine order of tending to your cats that you use whenever you clean the litter trays, feed, groom, or just generally pet your cats, always dealing with the least infected area first.
Since FCoV is very infectious and, obviously, is invisible, we can inadvertently have some of it on our hands, shoes or clothes when moving about the cattery. Therefore it is a good idea to wash or even disinfect our hands before every visit to the kitten room. People with a lot of cats might even want to keep a pair of shoes or slippers and perhaps a housecoat permanently in the kitten room to put on before handling the kittens. Large rescue catteries should have disinfectant foot baths between each major area of their catteries.
The kittens should have food bowls, litter trays and poop scoops which are only used for them and these should be cleaned daily and disinfected once or twice a week. Sally Matthews, from the Glasgow Cats Protection Shelter, had the wonderful idea of colour coding the beds, dishes, litter trays and scoops of cats in different areas of the cattery, so that it was immediately obvious if something was in the wrong place in the cattery. Thus, if a kitten's litter tray had been inadvertently put into the pen of an adult cat, it could be spotted instantly, removed and disinfected before being put into the kittens' area again.
3. Early weaning and isolation of
kittens to prevent their becoming infected with FCoV
Removing the kittens from their mother at 5-6 weeks of age prevents them from becoming infected, even if their mother has been shedding FCoV. Ideally, the kittens should be moved to a new, clean, room, but many cat breeders do not have a lot of room and have to be content with removing the queen, giving the room a good vacuum, and changing the litter tray and bedding.
Knowing the queen's antibody status at this stage is very useful for several
if the queen has an antibody titre of zero (by the immunofluorescent antibody test used at the University of Glasgow Veterinary School*), then she is not shedding virus and it is safe to leave her with her kittens for as long as you wish - no need to early wean! (though isolation is still essential unless your other cats are also antibody titre zero)
the lower the queen's antibody titre, the fewer protective antibodies the kittens will have received in their mother's milk
the higher the queen's antibody titre, the more protective antibodies the kittens will have received in their mother's milk, but also the chances of her shedding FCoV are higher
about one in three cats with FCoV antibodies is shedding FCoV at any one time
* There are many different FCoV antibody tests of widely varying quality on the market. The statements made on this website about antibody testing are ONLY relevant to the immunofluorescent antibody test used in the Feline Virus Unit, University of Glasgow Veterinary School since that is the test used in my research. The Feline Virus Unit receives blood samples for FCoV antibody testing from all over the world - just ask your vet to send your cat's blood sample to the Feline Virus Unit, University of Glasgow Veterinary School, Bearsden Road, Glasgow, G61 1QH, UK if you want your cat tested by our test.
Many breeders are reluctant to blood test a pregnant queen for FCoV antibodies because it may stress her. Some will have tested the queen prior to mating, which is the best option, although an uninfected queen could become infected at stud, so her status may have changed by the time she kittens. It is not a good idea to stress her immediately after kittening, as she may then reject her kittens, so she could be tested from 2 weeks after giving birth.
kittens to ensure they have been
successfully protected from FCoV infection
Kittens under 10 weeks of age may be infected but some are too young to have produced antibodies of their own. Most kittens are able to make antibodies by 10 weeks of age, so it is inadvisable to test kittens younger than 10 weeks old, and 12-16 weeks is probably preferable.
Kittens which have an antibody titre of zero by the University of Glasgow immunofluorescent antibody test are safe to rehome.
Kittens which have an antibody titre of greater than zero should be further isolated, preferably on their own, and rested 4 weeks later. Sometimes some kittens in a litter have an antibody titre of zero while others have higher titres, in this case, the litter should be split up according to antibody titre. There are two possible explanations for this phenomenon: first, the kittens may have vestiges of antibodies from their mothers' milk (called maternal antibody) and at the 4 week retest these antibodies will usually have disappeared. Secondly, the eary weaning and isolation procedure may have broken down somewhere, and the kittens have become infected, if this is the case, the kitten's antibody titre may have increased at the second test. While the majority of infected kittens will get over the infection, there is a very real danger of the kitten either developing FIP or infecting cats in a new home.
Already there have been successful prosecutions of breeders who have sold FCoV infected kittens, both under the UK Sale of Goods Act and also the Prevention of Cruelty to Animals Act. Cat breeders who sell kittens which are FCoV infected are risking prosecution.
If you have kept a kitten in isolation for many weeks and his or her antibody titre has not decreased and you are absolutely unable to keep the kitten, he or she should only be rehomed to a household with NO OTHER CATS (although one could rehome two antibody positive kittens together). The new owner should be fully informed that the kitten might be shedding FCoV and so could be infectious to other cats, and carries about a one in ten risk of developing FIP, which the stress of rehoming could precipitate.