Usenet 1994 October/usenetsourcesnewsgroupsinfomagicoctober1994disk1.iso/answers/cats-faq/leukemia

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From: erin rebecca miller <[e-mail]>
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Subject: rec.pets.cats: Feline Leukemia FAQ
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Summary: This is a faq on feline leukemia.
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Archive-name: cats-faq/leukemia
Version: 1.0
Last-modified: 5 June 1994
Periodicity: 20 days

This is part of the suite of FAQ's for rec.pets.cats.  It is posted
every twenty days.  Updates, additions, and corrections (including
attributions) are always welcome: send email to one of the addresses
below.


FELINE LEUKEMIA VIRUS FAQ
    (dedicated to Oliver, in the hopes they'll find a cure...soon)

Author(s)
    Written by Erin Miller ([e-mail]) with help
from James Golczewski, Edwin Barkdoll, Cindy Tittle Moore and Jeff
Parke.  Additional thanks to Wilf Leblanc, Dan Kozisek, Karen Kolling,
Isako Honshino and Patty Winter for their comments.


    The purpose of this FAQ is to answer frequently asked questions
about the Feline Leukemia Virus (FeLV). The Feline Leukemia Virus is a
virus which suppresses your cat's immune system. A cat which becomes
infected with the virus becomes susceptible to many ailments or
breakdowns in its system. The *virus* was somewhat inappropriately
named because it is different than the *disease* Feline Leukemia. A
cat which tests positive for the virus will not necessarily contract
the disease Feline Leukemia.  However, cats which do test positive for
the virus are more likely to catch any one of a number of diseases
including, but not limited to, leukemia, lymphoma or opportunistic
infections. This FAQ is divided into two parts; the first consists of
information every cat owner should know or should ask about the
virus. The second part is information for people whose cats have
tested positive for the virus.

** PART I: General info about FeLV **

Q. What is Feline Leukemia Virus and can I catch it?

A. Feline Leukemia Virus is a retrovirus which is specific to cats
   only.  It is considered to be the most common cause of serious
   illness and death in domestic cats. It causes a breakdown in your
   cat's immune system causing your cat to become susceptible to many
   diseases which it might otherwise be able to fight off. It CANNOT
   be transmitted to humans (including children) nor can it be
   transmitted to other species such as dogs.

Q. How is it transmitted?

A. FeLV is transmitted via saliva, mucus, urine, feces and blood. This
   means grooming, biting, sneezing, hissing, sharing food/water bowls
   and sharing litter boxes are all possible means of transmission.

Q. Will I infect my healthy cat if I pet an FeLV+ cat, then pet my
   cat?

A. No. FeLV needs to be transferred through the media above, and will
   not live long outside the host (the infected cat). Warm, dry
   environments will deactivate the virus and common household
   detergents and disinfectants will eliminate it from any contacted
   surfaces.

Q. What does the virus do to a cat?

A. In sum, once the virus gains entry (usually via saliva or mucus
   membranes) it will reproduce in the lymph tissue which is your
   cat's first system of immune defense. Some cats are able to mount a
   successful immune response against it and defeat the virus at this
   stage. In cats who don't successfully destroy the virus here, the
   virus will then move into the bone marrow where red and white blood
   cells are produced. It may stay latent in the marrow for many
   years. After that it will attack other tissues including causing a
   breakdown in several stages of the immune response system.

Q. Is there a vaccine?

A. Yes, there are several commercial vaccines available. Unfortunately
   the USDA does not have standard requirements for FeLV vaccines, so
   different manufacturers can publish 'Effectiveness Ratings' which
   cannot be compared with each other due to a lack of uniformity in
   testing terms and requirements. Estimating the effectiveness of the
   vaccines is difficult and most vets I've spoken with estimate them
   to have ~75-85% effectiveness (this means cats challenged with the
   virus will fight off infection 7-8 times out of ten). Published
   studies show that there are irreconcilable differences and bias in
   Effectiveness Ratings put out by the manufacturers so currently it
   is impossible to estimate the actual effectiveness of and between
   vaccines.  Suffice it to say that your cat is MUCH better off
   having received the vaccine, but the vaccine is not 100% effective
   so you should not expose your cat to undue risks. (Note: NO
   vaccine, whether it be for cats, dogs or people, is 100%
   effective. Some are about close to being as fully effective as
   possible, however the FeLV vaccine is not one of them).

Q. If I don't get my cat vaccinated, what are its natural defenses
   against the virus?

A. According to the literature, neonatal kittens are 100% susceptible
   to catching the virus from one exposure. 8-week-old weanlings are
   85% susceptible from one exposure. There is serious debate in the
   literature over the likelihood of non-vaccinated, healthy adult
   cats becoming infected with the virus but it seems that ~40% of
   cats exposed become immune, ~30 percent become persistently
   infected (show acute signs of a related-disease) and ~30 percent
   become infected, but the virus is latent in their system. (Hardy,
   et al, 1980).

Q. Is the vaccine expensive and how often do my cats need to be
   vaccinated?

A. After your cat has gone through its more elaborate set of
   kitten-shots, the FeLV vaccine should be given once a year. Prices
   vary between vets, locally and nationally. I surveyed readers of
   rec.pets.cats and contacted vets around the country and found that
   prices for the vaccination alone cost between $9 and $30
   dollars. The average was $18 (not including the vet-visit
   charge). It seems that the FeLV test costs about the same, but I
   didn't do a full-scale survey.

Q. If I get my cat vaccinated, isn't there a chance that it will catch
   the virus from the vaccine?

A. No. As of July 1992, all of the vaccines which are approved for
   sale in the United States are incapable of causing a positive FeLV
   test result. (Sorry, but I don't have figures for vaccines in other
   countries. If anyone does, feel free to append them onto this FAQ.)

Q. Do I have to get my cats vaccinated?

A. No one can force you to vaccinate your pets, though there are laws
   in some areas regarding certain diseases like rabies. Check with
   your vet to see what vaccines are required.

Q. My cats are indoors-only. Why should I bother getting them
   vaccinated?

A. You never know when your cat may escape to the outside, even for
   only a short period. Many people who lived through Hurricane Andrew
   or the LA Earthquake can tell you that some of their indoors-only
   cats ended up on the street for days. Fortunately disasters like
   these are infrequent, but the point is accidents can happen -- you
   never know when the plumber is going to leave the front door open
   for too long, or a visitor won't realize your cats are not allowed
   out, or whatever. In the few hours or days that your cat is outside
   it could come in contact with an infected cat, and it is better to
   give your cat that 75-85% boost to its natural resistance.

Q. My cat gets sick after it gets vaccinations. Why should I put my
   cat through that?

A. Some cats do have bad reactions to vaccines. However, it is better
   to have a cat sick for one day per year from being vaccinated than
   to have it die a miserable death from an FeLV-related disease. If
   your cat has a bad reaction to a shot, ANY shot, and the reaction
   lasts more than 12-24 hours, you should immediately bring your cat
   to the vet. Even if your cat has a mild reaction, you should at
   least discuss the matter with your vet to see what are the best
   options for next year's vaccinations. It may be best to spread your
   cat's annual vaccinations out over a few months, or have them all
   administered at once. This is definitely a matter which should be
   discussed with your veterinarian.

Q. I already have cat(s) and I found another which I want to bring
   home. What precautions should I take regarding FeLV (and FIV)?

A. This depends on the environment the new cat comes from. If it is a
   stray, or from a shelter which does not routinely test for the
   viruses (make sure you ask this of any shelter you visit), or from
   a household where you have reason to doubt the person has had the
   cat vaccinated, then keep the new cat separated from yours until
   you can have a vet examine it for many things. Keep it in a
   separate room and provide its own food dish, water bowl and kitty
   litter. DO NOT let your cats share any of these things, or share
   the same space, until your vet checks out the new one. If it is a
   feral cat, it may never have been vaccinated against FeLV and
   Rabies, or if it was a housecat it may be past its time for an
   update and have been exposed. Cats which have been on the street
   may also have ringworm or other parasites which are transmittable
   to you and your pets.

Q. How is FeLV detected?

A. Your vet will do a blood test; there are two types of blood tests
   which can be performed. Some vets will automatically do one of the
   tests before vaccinating your cat to make sure it is not already
   positive for the virus. The first (ELISA test) is where the vet
   takes some of your cat's blood, mixes it with a chemical and
   watches for a color change. If the blood changes color then your
   cat has tested positive for the virus. False positives are not
   uncommon in this form of test, so if your cat tests positive it may
   be a good idea to have it retested. "Light positives" are where the
   treated blood only changes color slightly. This means your cat is
   infected with the virus, but the virus is not very active in its
   system. The second type (IFA test) involves sending the blood
   sample to a special lab. This lab tests to see if the virus is
   being produced in the bone marrow. If this second test is positive,
   it is unlikely that your cat will ever test negative. Below is a
   flow chart (from a lecture by Dr. William Hardy, U of Penn. Vet
   School) which depicts what you should do if your cat tests positive
   on the ELISA test:

     Do the ELISA antigen test

     If (+) =>  - healthy or sick confirm by Indirect Fluorescent
                  Antibody test (IFA)

     If (-) =>  - if healthy and *not* exposed to a positive cat then no
                   need to retest
                - if healthy but *exposed* to a positive cat then retest
                  in 3 months because the healthy cat may be incubating
                  the virus.
                - if sick then confirm the ELISA test with an IFA test

Q. So some cats who test positive can later test negative?

A. Yes. If you have a cat which tests positive on the ELISA test, you
   should immediately have an IFA test done. If it tests negative on
   the IFA test, you should have your cat retested with the ELISA test
   in 3 months. If a cat does not test negative again in roughly three
   months, chances are it will always test positive. Vets and Virologists
   have devised an entire classification scheme of the different types of
   infected cats (transciently infected, persistently infected, etc.)
   based on the ELISA and IFA tests. It can be very confusing and if
   you are interested in learning the details you should consult with
   your vet regarding your particular cat's status.

Q. How long does a cat who tests positive have to live?

A. There is no set time period for how long an FeLV+ cat will
   live. One person on the internet said they had a cat which lived
   for 20 years with the virus, while others have given dates as long
   as 10 or 12 years, although these are probably extremes. I have not
   found any truly long-term studies to document, but it seems that of
   the studies done, 83% of FeLV+ cats do not live beyond 4 years.
   (Hardy, et al 1980). All cats which do not later test negative, but
   in all other ways are healthy, are carriers for the virus. Even
   though they do not have acute symptoms, they can still spread the
   virus to cats which are not infected. Often people do not have
   their cat tested for the presence of FeLV until the cat is
   noticeably sick, and by this time the FeLV-related disease may have
   progressed too far for the cat to recover.

Q. What are symptoms for which I should be on the lookout?

A. Unfortunately, since FeLV is a retrovirus which attacks your cat's
   immune system, your cat can become ill from many things as a result
   of the virus. This makes looking for a 'sure sign' very
   difficult. Often the immune system is weak so your cat will become
   chronically infected with certain conditions such as stomatitis,
   gingivitis, oral ulcers, abscesses and non-healing wounds of the
   skin, upper respiratory infections or FIP. Some cats whose
   digestive tracts are affected have been described as staring at
   their food bowl seemingly unable to remember how to eat. Basically,
   whenever your cat shows chronic, peculiar and/or unhealthy
   behavior, take it to a vet to be examined.

** PART II: If your cat has tested positive **

     Some of these points are mentioned in the general section above,
but here are more specific questions geared to people whose cats have
tested positive.  The most important point to stress is that FeLV+
cats *MUST* be made indoors-only. This needs to be done for two
reasons. First, the more you expose your cat to outside ills, the more
likely it is to contract an FeLV-related disease or infection. The
second reason is that FeLV+ cats are like Typhoid-Marys to any other
cat they meet. As noted above, the vaccine is only 75-85% effective,
so any vaccinated cat that your cat encounters is at risk, as well as
any stray.  If these cats are then infected and they continue to
interact and infect other cats, then you could give rise to an
epidemic in your area. If you cannot or will not keep your FeLV+ cat
indoors, than the only humane thing to do is find a home for it with
someone who will (ways to do this are suggested below), or have your
cat put to sleep. This may sound extreme, but it is extremely selfish
to allow your cat to roam the neighborhood possibly infecting all the
local outdoor cats just because you refuse to keep your cat indoors.
Keeping your cat indoors is one of the responsibilities of owning a
infected cat.

Q. My cat has tested positive. Should it be put to sleep?

A. The mere fact of testing positive is not enough to merit putting a
   cat to sleep, although there may be other significant factors
   involved which do make putting the cat to sleep the best
   option. There *are* vets who recommend putting all FeLV+ cats to
   sleep. If your vet recommends this and you feel comfortable with
   that decision, then that is the best solution. Sometimes putting an
   FeLV+ cat to sleep *is* the best option for the cat, especially if
   it has acute symptoms and is in pain. This is never an easy
   decision and one which should not be taken lightly. If you do not
   feel you are capable of emotionally dealing with having an FeLV+
   cat (or cannot keep the cat indoors), but do not want to put the
   cat to sleep, there are other alternatives which are discussed
   below. The one thing you should not do is ignore the virus. If your
   cat has tested positive, then you have a responsibility to take
   some action. *Feline Leukemia Virus will not go away if you just
   ignore it!*

Q. What will happen to my cat now that it has tested positive?

A. Because there are so many different ways to respond to the presence
   of the virus, it is impossible to predict exactly what will happen
   (and when it will happen) to your cat. I've noticed that any 5 vets
   you ask will give you 5 different answers to this question. The
   scientists who experiment and publish on the disease are also in
   disagreement. I have presented two different (published) viewpoints
   below. According to Hardy, et al (1980), (and these people seem to
   be the authorities on the disease) roughly half of all cats who
   test positive (and do not test negative within a three month
   period) are persistently infected and show acute signs of
   FeLV-related diseases. The other half are latently infected and are
   in all other aspects 'healthy' although they are still
   carriers. 17% of all cats which test positive (and do not later
   test negative) will live past 4 years. The next point of view is
   taken from a much more recent article and has radically different
   statistics. According to Loar (1993) of cats which test positive
   for the disease only 5% will immediately become infected with an
   FeLV-related disease. The other 95% will enter the latent phase
   which will last for months to years. These 95% are still carriers
   for the disease and can infect other cats.

Q. Although my cat has tested positive, it is healthy in all other
   respects. How can I prevent an FeLV-related disease from becoming
   active in its system?

A. There is no sure way to keep your cat healthy. Eventually, an
   FeLV-related disease will probably develop no matter what you
   do. However, one way in which a disease is likely to develop is if
   you stress your cat's system. If a cat's system is stressed, its
   body can't put as much energy into fighting off illnesses (just
   like you always seem to get sick during exams or when you have to
   make a presentation to your boss). "When all my cat does is eat and
   sleep 20 hours a day, how can it possibly be stressed?" you may
   ask. Anything which is upsetting or unpleasant for your cat may
   stress it, such as going for very long periods without food or
   water, overcrowding, movement to new territory, territorial
   conflicts, sending your cat to be boarded for long periods of time,
   or pregnancy and lactation.  (Of course one should NEVER breed a
   FeLV+ queen as it will expose not only the tom, but all the kittens
   will be FeLV+. There is also an indication, although no proof, that
   FeLV causes abortions in queens.  For the same reasons, neither
   should FeLV+ toms be bred.)  Basically, keep in mind things which
   you have noticed in the past that seriously upset your cat. These
   are things which are more likely to lower your cat's natural immune
   system and give a disease the chance to attack.

Q. Should I continue to vaccinate my cat if it is FeLV+?

A. The literature recommends against continued FeLV vaccinations.
   Other feline vaccinations (panleukopenia, rabies, etc.) should be
   continued.

Q. I have had several cats for a long time. One of them recently
   tested positive, but the others have not. Do I need to get rid of
   the FeLV+ one?

A. This is a tough situation, for which there is no pat answer. You
   should discuss the matter with your vet. One vet I spoke with felt
   that chances are the other cats have already been exposed and it is
   probably best to just keep them up on their vaccinations and not
   change the household drastically. One study (Barlough, 1984) says
   that in a survey of 45 households from which FeLV+ cats were
   removed, 99.5% of the FeLV- cats remained negative. However
   households in which the FeLV+ cats were not removed had infection
   rates 40 times greater.  It is probably best to remove the infected
   cat if it can be sent to a good home without causing too much
   disruption in your household.

Q. I have an FeLV+ cat and I want to find it a playmate. What should I
   do?

A. There a few options. The only thing which you really ought NOT to
   do is get a healthy cat as a playmate or let your cat outside for
   excitement. Dogs cannot become infected with the Feline Leukemia
   Virus, and some dogs and cats, especially those raised together can
   be very close. One word of warning: getting a dog (or any pet) for
   the sole reason of keeping a cat company is not a good idea. If you
   consider getting a dog, make sure you understand the amount of time
   and responsibility that goes into caring for a dog (which is much
   more than that of a cat); otherwise you will regret the decision
   and both you and the dog will suffer. (There are excellent dog FAQs
   which will give you as much information on the matter as you can
   handle).

   The other option is getting another FeLV+ cat. The obvious down
   side is that you not only have twice the vet bills, but you also
   put yourself at risk for twice the heart-ache when one or both
   become ill. However, if you are willing to take the risk you can
   search for FeLV+ cats by putting an ad in the newspaper and calling
   all your local vets and animal shelters and explaining your
   situation. They may put you on a list and should they receive any
   cats which test positive, they may give you a call. Make sure you
   give your current vet as a reference as most shelters and other
   vets will want to make sure you understand the responsibility of
   owning an FeLV+ cat or to make sure that you are not some sociopath
   looking for sick kitty-cats to do nasty things to.

Q. I have an FeLV+ cat that is otherwise healthy, I do not want to put
   it to sleep, but I can't keep it. What can I do?

A. Similar to the above answer, place ads in the newspaper and contact
   your local shelters and vets and tell them you have an FeLV+ cat
   which you are willing to give to a good home. A good home is
   someone with another FeLV+ cat, or someone who does not have any
   other cats and will keep the cat indoors. Also, there are animal
   shelters which specifically take in FeLV+ cats. Again, contact your
   local vets and shelters to see if they are aware of any such haven
   to which you could send your cat. Almost all regular shelters will
   put to sleep any cat they receive which tests positive because the
   virus is so contagious.

  If you choose to put an ad in the paper you MUST take the
   responsibility of making sure the people who express interest in
   your cat are doing so for legitimate reasons. You should interview
   them in person and check references if possible. There *are* people
   who will lie to get cats to feed to other pets, to sell to labs or
   to abuse. Think about this as you interview each potential
   candidate.


References:

Hardy, William D., Essex, Myron, and McClelland, Alexander J.
   (eds). _Feline Leukemia Virus_. Elsevier/North-Holland, Inc. New
   York, 1980.

Loar, Andrew S. "Feline Leukemia Virus: immunization and
   prevention" in _Veterinary Clinics of North America: Small Animal
   Practice._ 23(1):193-211, 1993.

Barlough, J.E. "Seriodiagnostic aids and management practice
   for retrovirus and coronavirus infections" in _Veterinary Clinics of
   North America: Small Animal Practice_ 14(5):955-969, 1984.

Olsen, R.G. et al "Oncogenic viruses of domestic animals: in
   _Veterinary Clinics of North America: Small Animal Practice_
   16(6):1129-1144, 1986.

   Also, the _Journal of the Am. Vet. Med. Association_, 199(10), Nov. 15, 1991
is devoted entirely to feline viral diseases.

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This article is Copyright (c) 1994 by Erin Rebecca Miller.
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