Great observations and lots of mystery with this horrible disease. It would be great if you can find out from that book about what an antigen is and how it works with the virus.

I'm no expert but have researched so much. It would be such a relief to all of us if we knew if the virus could be shed if the ELISA test is a true positive (meaning it is in their saliva, blood, etc) or does it have to reach the bone marrow first? Maybe that could also explain why some contract it and others don't. Am I making sense? It is confusing because it's not B&W. There are too many exceptions with the FeLV. If you find out anymore, please share :)

Thanks for your input/research!
----- Original Message ----- From: "Maureen Olvey" <>
To: <>
Sent: Tuesday, August 02, 2011 6:23 PM
Subject: Re: [Felvtalk] doubts on two FeLV positive kitties

I always thought they could spread it if positive on ELISA but the book
didn't say that so I wonder.  The book made it sound like they would
only be shedding the virus and contagious if the IFA was positive.  It
said that the ELISA test for the virus antigen that's in the
blood, serum, saliva and tears.  I looked up antigen before to see
exactly what that was,  you know like whether it was the virus itself or
like an antibody, but I don't remember what it said.  I know it's not
like an antibody.  I'm not in the medical field so I have to look up a
lot of stuff.  So is the virus antigen the same as the virus itself?  I
need to go look that up again to try to understand again exactly what an
antigen is.  If the virus antigen is in the blood and saliva and the
antigen is the same as the virus then why couldn't they spread the virus
if the ELISA test is positive but the IFA test negative.  I've just
confused myself all over again  ;-)

Interesting enough, somewhere
else it did say that if there was a latent infection, meaning the virus
is only in the bone marrow and T-cell lymphocytes (whatever that is), a
mama cat could infect her kitten in utero or while nursing.  I'm not
sure if that means that the virus reactivates during pregnancy or if the
kittens can get a dormant virus.  It's all so confusing.

But, I
would like to know if the virus can be shed when the ELISA is positive
but the IFA is negative so if anybody has any thoughts let me know.

“I am not interested to know whether vivisection produces results that are profitable to the human race or doesn’t….the pain which it inflicts upon unconsenting animals is the basis of my enmity toward it, and it is to me sufficient justification of the enmity without looking further.” – Mark Twain

Date: Tue, 2 Aug 2011 18:00:22 -0500
Subject: Re: [Felvtalk] doubts on two FeLV positive kitties

I wonder if the cats/kittens can shed the virus if a positive is on an ELISA
test?  That would be so helpful to know, but I read that scientists could
not determine when the virus actually sheds :(

----- Original Message ----- From: "Maureen Olvey" <>
To: <>
Sent: Tuesday, August 02, 2011 5:31 PM
Subject: Re: [Felvtalk] doubts on two FeLV positive kitties

Those two little babies are so adorable.  I really hope they turn out to
 be negative.  How did you manage to get them to be still to take such
great photos?  When I try to take photos of my fosters for our website
they are too busy playing to sit still for a photo shoot.

I didn't foster the mama kitty or kittens that had FeLV but last I heard
 they waited like a month and a half and did the IFA on the mama kitty
which turned out to be negative.  They did individual snap test on the
four kittens.  Two of the four kittens tested positive on the snap test
and the other two tested negative.  So weird.  They were able to adopt
out the two negative kittens, same home I believe, although they did
tell the adopters about the Mama and the two positive littermates.  The
other two littermates haven't been adopted yet.  I'm not sure about the
Mama cat.  I'll have to e-mail them to find out what's going on right
now.  They really need to re-test the Mama and the two positive kittens
and I don't know if they realize it.  Good thing you sent this e-mail so
 I'd remember to talk with them.

I have this book called "The Cat Owner's Home Veterinary Handbook" which
 is written by several different vets and I'll write exactly what they
say about testing.  It's a little long so just ignore this next part if
you don't want to know.

"Currently there are two tests available to detect FeLV infection.

1.  The IFA test, performed by a reference laboratory, detects virus
antigen in infected white blood cells.  This indicates that the bone
marrow is infected and there is a high probability that the cat is
persistently viremic and is shedding the virus in his saliva, making him
 infective to other cats.  About 97 percent of IFA positive cats remain
viremic for life and never extinguish the virus.

2.  The ELISA test detects virus antigen in whole blood, serum, saliva
and tears.  Blood is the recommended sample for testing.  A rapid
screening leukemia test kit is available for home and veterinary clinic
use.  The ELISA test is more likely to detect weak, early, or transient

The common practice is to screen for FeLV using the ELISA test.  If
positive, the cat may have a transient viremia from which he will
recover completely, or he may be in the early stages of a progressive
infection.  A positive ELISA test should be confirmed with an IFA test.
 A positive IFA test indicates that the cat is shedding virus and is
capable of infecting others.

The ELISA test should be repeated in 8 to 12 weeks to see if the virus
has been eliminated.  The IFA test should also be repeated at this time
because if the cat was in an early stage of infection, the IFA initially
 may not have been positive but may become so after 12 weeks."

That's the direct quote from the book.  The books also mentions about
latent (dormant) type infections where the cat is able to eliminate the
virus from blood and saliva but the virus still persists in the bone
marrow and in T-cell lymphocytes.  It says "over many months the
majority of latent-infected cats overcome and extinguish the virus, so
the incidence of latent infection after three years is quite low."
During this period of latency though it talks about sometimes stress and
 illness can reactivate the virus.  As far as testing to find out if a
cat has a latent virus it says -

"Cats with latent infection test negative on both the ELISA and the IFA
tests.  This is because the virus is absent in both serum and white
cells.  The only way to diagnose a latent infection is to remove a
sample of the cat's bone marrow containing the dormant virus and grow
the cells in culture."

Well, that's what the book says anyway.  Not that it is an absolute
authority but most of the other reading seems to say the same thing.
What's funny is that you could have a cat that has a latent infection
and you would never know it unless the virus got reactivated and the cat
 became sick.  So you could do 10 different test on the cat and they
would all be negative but then a year later the virus could become
reactived then the cat tests positive.  I look at all my cats and my
fosters and wonder if any of them have a latent infection.  You just
never know and that's the really scary part.  One encouraging thing
though is that only about 30% of the cats exposed to the virus actually
become permanently infected and will die from the disease.  Of course
30% is still too many.

The problem we in rescue have is that keeping the cat for 12 weeks and
doing several different test before trying to adopt out is not always
possible.  It sucks.

As far as immune system stimulants, I'm not sure what to recommend.  I
hear of so many different things that I can't remember what does what
and what is good for what.  I would think a decent diet is a good basis
to start with.  Probably not the cheapest cat food they sell.  But the
supplements are just way too confusing for me.  Natalie and some of the
others might have some opinions.

Felvtalk mailing list

Felvtalk mailing list

Reply via email to