Yesterday, Sukie wrote:
 
>So, until there is actual, well challenged, rigorous testing it is
>really important to separate the choice to believe in a hypothesis until
>there is more data, from what is actually known.  That is only most fair.
 
I agree.  I'd like to review the evidence that raisins cause kidney
damage in ferrets.  On many ferret boards (including this one) it is
being stated as *proven* that raisins cause kidney damage in ferrets.
The first "link" in the chain of evidence is that raisins do cause kidney
damage in dogs.  From that, it has been extrapolated that they may cause
kidney damage in ferrets.
 
The ASPCA Animal Poison Control Center issued what they called a
"Nationwide Update" to the effect that "Raisins and grapes can be toxic
To dogs" in 2004.  It stated that "From April 2003 to April 2004, the
Center managed 140 cases, each involving one or more dogs that ingested
varying amounts of raisins or grapes.  Of these cases, over 50 animals
developed clinical signs ranging from vomiting to life-threatening kidney
failure, and seven dogs died." That's a pretty good arguement for not
feeding raisins or grapes to dogs.  And those statistics only represent
one year, there are more cases, every year.
 
A search of the APCC site today yields one hit for poisoning in ferrets
by ibuprophen,(forty cases reported) but none for ferrets and raisins.
 
All right.  I can see why people would reasonably wonder if given the
problems dogs were having, ferrets could be affected as well, given that
so many ferret hoomins feed raisins, often *multiple* raisins, on a
sometimes daily basis.  I am concerned myself, but a concern is not
*proof*.  When I ask for *proof*, I am looking for hard evidence such
as the case histories the APCC site can refer me to on raisin toxicity
in dogs, and ibuprophen toxicity in ferrets.  (Again--one hundred and
forty cases in dogs, forty for ferrets and ibuprophen)
 
As "Proof" I am referred to a talk given during one of the International
Ferret Congress Symposiums.  A vet whose name has been given to me as
"Dr. Kawasaki" gave a talk about "several" (I don't know the number, I
have had several quoted to me and they don't match) cases of suspected
kidney toxicity in ferrets due to raisin ingestion that he has seen in
his practice.  HOWEVER--as everyone who cites me this talk as "proof"
has also said, the material has not been published, where it would be
subject to peer review.  Or seen by me, or by you.  Given that, what may
be very important data falls to the level of nothing more than anecdotal
evidence.
 
Before I go any further, let me make it CLEAR that I don't know Dr.
Kawasaki,(I hope I have the spelling right) I have no bad feelings
toward him and do not wish to impugn his professional abilities in any
way.  I would really like to hear what he has to say.
 
I also wish to make it clear that a talk that only a small number of
people (relative to the size of the ferret community as a whole) attended
several years ago that doesn't seem to be available to the public *today*
is NOT proof that raisins cause kidney damage in ferrets.  In fact, when
we review today's assertion that "Raisins cause kidney damage in ferrets"
we see one untested hypothesis--raisins cause kidney damage in dogs, thus
by extrapolation, they will also cause kidney damage in ferrets, and some
anecdotal evidence that is not subject to scrutiny or peer review--one
veterenarian claims evidence of kidney damage in ferrets because of
raisin ingestion.
 
An untested hypothesis is not proof.  Anecdotal evidence is not proof.
Fervent assertion is not proof.  WHY THEN, are so many in the ferret
community demanding that it has been *proven* that raisins cause kidney
failure in ferrets?  People well-versed in basic science, who should
know better?
 
There are several good reasons to shy away from feeding raisins.  They
are dried fruit, and cannot be digested by ferrets.  Dried fruit has been
associated with intestinal blockages in ferrets, although one usually
hears about the hard dried fruit chips being a problem, not soft raisins.
They are very high in sugar, and really represent "empty calories", "junk
food." For a ferret already having trouble maintaining a healthy blood
sugar, (and how many of us know off hand if our ferrets do or don't?)
probably feeding them a huge slug of sugar isn't a good idea.  If you
feed your ferret some raisins, and then look in his mouth at his teeth
(ferrets just love science, they won't mind if you look!) you will see a
goodly amount of sugary raisin debris stuck in his molars.  This probably
isn't any better for his dental health than it would be for yours.
 
I have no problem with anybody concerned about their ferret's health
saying "Well, we lived with dogs for thousands of years before we found
out grapes and raisins made them sick.  I'll play it safe and stop
feeding raisins to my ferrets."  No ferret ever died from a lack of
raisins.  But I'd really appreciate it if the next person who claims to
have "proof" of a direct, causal relationship between raisins and ferret
kidney damage had some....proof.  Not a passionate conviction.  People
are getting snarled at on ferret boards for feeding raisins.  All it does
is get people upset, and it doesn't bring us any closer to a straight
answer.  Bad science is just that.  *Bad*.
 
Alexandra in MA
 
(Not a research scientist, but paid my dues teaching basic science to
high school freshman.  Loading mercury with a pitchfork is about as
easy.)
[Posted in FML issue 5188]