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Proceeding of the NAVC
North American Veterinary Conference
Jan. 8-12, 2005, Orlando, Florida
Reprinted in the IVIS website with the permission of the NAVC
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Published in IVIS with the permission of the NAVC
The North American Veterinary Conference – 2005 Proceedings
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IFATs of less than 100 have been shown to shed virus, so it
is important to use a laboratory where the first dilution they
use is low, e.g. 1:10.
PREVENTION OF FIP IN CAT SHELTERS
Diane D. Addie, PhD, BVMS, MRCVS
University of Glasgow
Scotland, United Kingdom
www.catvirus.com
FIP is a major problem in cat shelters, and indeed for cats
from any multicat environment. There is currently only one
FIP vaccine, Primucell® which prevents 50-75% of FIP
deaths. Since the vaccine is not 100% effective (and no
vaccine is!) the main way to prevent FIP is to attempt to stop
cats from ever being exposed to the cause of FIP: feline
coronavirus (FCoV). Thus, in shelters, an understanding of
FCoV shedding and rigorous hygiene precautions are still the
most effective ways to contain this disease. In view of the
large numbers of infectious diseases which can infect cats,
rigorous hygiene should be in place in any case. Stress
reduction is also an important factor, since the development
of FIP is often preceded by a stressful episode in the cat’s
life.
FCoV SHEDDING AND TRANSMISSION
The main source of virus is the faeces and infection is by
accidental ingestion of particulate faeces (e.g. from grooming
paws after using a litter tray, or airborne particles from litter
tray contaminating food). FCoV is a fragile virus, surviving
only days outdoors, but can survive up to 7 weeks in dried up
faeces in cat litter particles. FCoV is shed only transiently in
the saliva in a few cats. FCoV does not generally cross the
placenta. Around 20% of cats have antibodies to FCoV,
rising to over 50% of purebred cats and 83% of cats at
shows. FCoV is very infectious and once in a household, will
infect at least 90% of cats.
Virus shedding begins around 2-3 days after infection, and
seroconversion about 18-21 days post infection.
The majority of cats become transiently infected, shed FCoV
for 2 –3 months, become seropositive, stop shedding virus,
and become seronegative at which time they are susceptible
to re-infection. Thirteen percent of infected cats become
healthy lifelong FCoV carriers, continually shedding FCoV in
their faeces.
Cats shed literally billions of viral particles in their faeces
and the stress of entering a rescue cattery will cause virus
shedding to increase hugely.6
LITTER TRAYS AND CAT LITTER
See Table 1. Use a non-tracking cat litter (for example Cat
Country – contact Linda Turco for details, email
mmeadows@tein.net).
In the laboratory this litter has
virucidal effects against FCoV. However, FCoV transmission
has occurred even in the presence of virucidal cat litter –
regular declumping and good hygiene are still essential.
FCoV ANTIBODY TESTS
The indirect immunofluorescent antibody test (IFAT) from
the University of Glasgow is the gold standard antibody test.
It gives an antibody titer that is useful for comparison in
sequential testing and contains an internal negative control at
each dilution, so that false positive results do not occur.
Samples divided into 5 and sent to 5 different laboratories in
the USA gave 5 different results (Postorino Reeves, personal
communication).
Thus the usefulness of antibody testing
depends very much on using a good quality test. Cats with
FCoV VIRUS TESTS
RT-PCR detects the RNA of the FCoV. Detection of FCoV
RNA in the blood or faeces is not diagnostic of FIP, since
around 25% of healthy seropositive cats, or animals with nonFIP illness, are also positive. (Although positive RT-PCR of
an effusion may well be diagnostic of FIP.) The use of RTPCR in FCoV control is limited because cats can shed FCoV
intermittently, so a single negative or positive test is
meaningless but repeat tests are useful. Determination of
carrier cats requires 9 monthly consecutive positive faecal
PCR tests. Determination of a cat having eliminated FCoV
infection requires 5 consecutive negative faecal RT-PCR
tests, or that the cats’ antibody titer has returned to less than
10.
CONTROL OF VIRAL TRANSMISSION BY HYGIENE
AND BARRIER NURSING
The key to prevention of FIP is to prevent FCoV infection.
Largely, this is done by keeping infected and uninfected cats
apart, and by excellent hygiene. See Table 1. FCoV infection
is perpetuated by a cycle of infection, virus shedding,
development of immune response, loss of immune response
and re-infection. In breeding catteries and ordinary pet
households, control has been effected by separating IFAT
seropositive and seronegative cats. Cats are tested every
3-6 months and as their antibody titre falls to 20 or less, they
are put into a seronegative group which is kept isolated from
the seropositive group.
The essence of "barrier nursing" is preventing transfer of
infection within the cattery. Every cat should be housed
singly, unless he or she came in with housemates. Never
touch a clean animal/food bowl/litter tray/pen after touching a
dirty one, unless you have thoroughly disinfected first.
Distribute the animals’ food before you deal with the litter
trays, cleaning kennels – better still - have different people
dealing with the food and the cleaning. Put out clean litter
trays in the runs first, then go back and pick up the dirty trays,
don’t touch a clean tray after a dirty one and never use the
same poop scoop from one pen to another!
The first rule is to deal first with the least infected area of
the cattery (i.e. if present: any kittens, surgery cases) and
gradually move up to the most infected area (where there are
sick animals with infectious disease or known healthy carriers
of infection). It is a useful idea to establish a routine order of
tending to the animals in a cattery so that whenever litter
trays are cleaned, the cats fed or groomed, or just generally
petted, the least infected area is always dealt with first.
We can inadvertently indirectly transmit viruses 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 cat pen. There should be disinfectant
foot baths between each major area of a cattery.
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. Colour
code the beds, dishes, litter trays and scoops of cats in
different areas of the cattery, so that it is immediately obvious
if something is 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.
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Small Animal – Shelter Medicine
Sneeze barriers are essential for the control of air-borne
viruses in all of the cattery. It is vital that air conditioning
draws the air past the cat straight to the outdoors or to a virus
filter system and not past other cats.
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FCoV PREVENTION IN KITTENS
Kittens are protected from FCoV infection by MDA which
probably wanes at around 5-6 weeks. This discovery
enabled the breeding of uninfected kittens even in
households where FCoV is endemic and their queen
infected.
Table 1. Protocol for minimising FCoV introduction or spread*
A. Reduce the numbers of cats in any area
♦ in rescue facilities cats should be kept singly
♦ cats should be kept in small groups according to their antibody or virus
excretion status
antibody or virus negative cats together
antibody or virus positive cats together
B. Prevention of kitten infection: early weaning and isolation
♦ rescuers of pregnant cats should follow the protocol outlined in Table 2.
C. Reducing fecal contamination of the environment
♦ have adequate numbers of litter trays - 1 tray per 1-2 cats
♦ litter trays should be declumped at least daily
♦ use a non-tracking and virucidal cat litter
♦ remove all litter and disinfect litter tray at least once a week
♦ site litter trays away from the food area
♦ vacuum around litter trays regularly
♦ clip fur off hindquarters of long-haired cats
♦ disinfect pens between occupants using 1:32 dilution of
sodium hypochlorite
♦ allow pens to lie empty if possible
D. Primucell vaccination
♦ all new entries into the cattery should be vaccinated with Primucell,
preferably two doses at least 4 weeks before admission into the cattery
*Based on recommendations from working groups of the international feline enteric coronavirus and
feline infectious peritonitis workshop.5
Table 2. Protocol for prevention of FCoV infection in kittens
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Prepare kitten
pens
1. disinfect pens between occupants using 1:32 dilution of sodium
hypochlorite
2. introduce queen 1-2 weeks before she is due to give birth
3. color code and dedicate litter trays, food and water bowls to
kitten section and disinfect frequently with sodium hypochlorite
Practise barrier
nursing
1. deal with the kitten section of the cattery before tending other
cats
2. clean hands with disinfectant before going into kitten section
3. have shoes and coveralls dedicated to the kitten section
Early weaning
and isolation of
kittens
1. test queen for FCoV antibodies either before or after kittening
2. if queen’s antibody titre is greater than zero, the kittens should
be removed to another clean pen when they are 5-6 weeks old
3. if the queen has an antibody titre of zero, she can remain with
the kittens until they are older
Test kittens
1. test kittens for FCoV antibodies at over 10 weeks of age
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MINIMISE STRESS IN THE FCoV INFECTED CAT
Around 1 cat in 10 who is infected with FCoV develops FIP.
Cats which have FCoV antibodies should not be stressed if at
all possible - for example, delay having them neutered or any
other operation which is not life-saving. In a state of the art
Cats Protection cattery in Scotland, cats were provided with
high-sided beds or cardboard boxes in which they could hide.
Use of feline pheromone (Feliway) diffusers may also help.
PRIMUCELL VACCINATION
Primucell® is an intranasal temperature sensitive FIP
vaccine manufactured by Pfizer. At time of writing, it is the
only licensed FIP vaccine. In my opinion, Primucell is safe
and effective and every cat coming into a rescue cattery
should have been vaccinated with it. Ideally, cats should be
tested for FCoV antibodies before vaccination to determine
whether or not they have already been exposed to FCoV
(since the vaccine will not work in a cat who is incubating the
disease).4 Also ideally, cats should have had their two doses
of vaccine 3 weeks apart well before being introduced into
the cattery, to give it time to work. However, in reality, it is
likely that rescued cats will be fortunate if they receive a shot
as they come through the door of the rescue cattery, that will
also save lives.7
ANY RISK TO PEOPLE?
Humans cannot be infected with feline coronaviruses. Cats
in areas where SARS is endemic may seroconvert and may
transiently shed the virus in oropharyngeal secretions.
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REFERENCES AND FURTHER INFORMATION
www.catvirus.com
www.gla.ac.uk/companion
www.felinecoronavirus.com – the SIFFS website
SIFFS proceedings in April 2004 edition of JFMS
1.
2.
3.
4.
5.
6.
7.
Addie, D.D. & Jarrett O. Feline Coronavirus. 1998
Infectious Diseases of the Dog and Cat. 2nd edition.
Editor: Greene, Craig. Published by W.B. Saunders
Company, The Curtis Center, Independence Square
West, Philadelphia, Pennsylvania 19106. 58-68 Third
edition due out soon.
Addie D.D, Schaap I.A.T, Nicolson L, Jarrett O. 2003
Persistence and transmission of natural type I feline
coronavirus infection. J. Gen. Virol. 84 (Pt 10), 27352744
Fehr D, Holznagel E, Bolla S, Lutz H., Hauser B.,
Herrewegh AAPM, Horzinek MC. 1995. Evaluation of
the safety and efficacy of a modified live FIPV vaccine
under field conditions. Feline Pract 23:83--88
Fehr D, Holznagel E, Bolla S, Hauser B., Herrewegh
AAPM, Horzinek MC, Lutz H. 1997. Placebo-controlled
evaluation of a modified life virus vaccine against feline
infectious peritonitis: safety and efficacy under field
conditions. Vaccine 15 10 1101-1109
Pedersen N.C., Addie D., Wolf A.
1995.
Recommendations from working groups of the
international feline enteric coronavirus and feline
infectious peritonitis workshop. Feline Practice 23:108111.
Pedersen NC, Sato R, Foley JE, and Poland AM. 2004
Common virus infections in cats, before and after being
placed in shelters, with emphasis on Feline Enteric
Coronavirus. JFMS.
Postorino Reeves N.
1995.
Vaccination against
naturally occurring FIP in a single large cat shelter.
Feline Pract 23: 81--82.
INFORMATION FOR CLIENTS
www.catvirus.com
Orion Foundation
http://www.devonheaven.com/users/orionsociety/
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