This is the last of the adrenal posts, to which I am sure some of you will
applaud. It has been hard for me as well, well maybe not from a boredom
aspect, but hard nonetheless; I had to give the inter-library loan people
a box of designer chocolates so they wouldn't complain. The greatest
difficulty has been the long-term posting; I think it would have had a
lot more impact if they had ran in a week rather than two. That was
unintentional and caused by MF debates, the Ohio bite case, and other stuff
which is also important. But those issues filled the FML and placed these
posts into the category of "I'll drop them in when I find space." Perhaps I
should have divided them into more posts, or posted several parts in a row
to get around the FML guidelines, but the work seemed to divide itself into
five parts, and I was too busy to argue with it. This last post will also
be long but hopefully will be posted sooner than the others. With the
publication of this post, feel free to pepper me with objects no larger than
a soda can, or questions, whichever you prefer. I will not answer rude
comments. I will provide specific references to those with a bonafide
interest.
250 years ago, the Philosopher David Hume said that you couldn't infer an
infinite cause from a finite effect. I have a photocopy of the paper in
which that statement was orginally written, and I look at it whenever I work
on any scientific paper. While the original purpose behind the statement
has little place on the FML, the statement itself can sum up the problems of
ferret adrenal disease. What can cause it? I came up with more than a
dozen really good ideas, but am no closer today at deciding what causes it
that I was three months ago when I started to look into the issue. In fact,
I think I know *less* now than then. Perhaps the answer has been
scotch-taped to my computer terminal all along; you cannot infer an infinate
cause from a finite effect.
What research I've done suggests adrenal disease in ferrets is a
multi-factorial problem resulting from a genetic predisposition and an
environmental trigger. Because the genetic heritage of ferrets is little
understood--we don't have coat colors worked out yet--that aspect of adrenal
problems has no current resolution. In other words, ferrets as a group may
be predisposed to adrenal problems, or just USA strains, or just specific
breeder strains; no one knows. After working on the genetics of the
problem, I'm inclined to believe it is a ferrets-as-a group predisposition.
Better statistics and controlled testing could resolve this problem in a few
years, provided funding and animals for research be provided. There are a
few studies, but they do not answer the question of which type of ferret
gets the disease, nor location.
Adrenal disease seems to be a geographically isolated disease.
Statistically, ferrets in outside of the USA and Canada (or America as in
"North") have significantly lower reported rates. Adrenal disease also
seems to be a modern disease; that is, after scouring all available records
for the last 200 years, I was only able to find a single incidence of what
*could* have been adrenal disease, and in that case, my "diagnosis" was
based on hair loss and thirst, and could have been something else. Even as
soon as thrity years ago, adrenal disease was uncommon enough to not be
mentioned in USA publications, including vet-care papers. Some might argue
the sudden onset is due to early ferret deaths--they didn't live long enough
for the disease to exhibit itself, or that the ferrets were simply killed
and no record was made. I reject both arguments because I actually waded
through reams of illness reports and cures. The average lifespan of ferrets
reported 100 years ago is essentially the same as today, except the average
age of death was a little bit lower. Certainly, they lived 4-5 years, which
in today's American population, would mean adrenal disease would have been
noted. Most authors made every attempt to mention illnesses that only had
the faintest possiblity of occurence. In an 1860's version of a vet how-to
book, the symptoms of Cushing's Disease is mentioned in dogs, and while the
aliments of ferrets took up a dozen pages, nothing similar was even remotely
mentioned. I don't think you can assume the disease was there but ignored.
These guys LOVED to get their names attached to a disease, as if they
invented it. I don't think they saw it or it was extremely rare.
Since the ferrets in the USA, Canada, Australia, and New Zealand all come
from the same basic stock, and those same ferrets show a tremendous amount
of variation in body shape, patterns, fur color, and other morphological
traits, arguing the American ferrets have some sort of inbred genetic
problem is rather pointless. It may be that the supposition is true, and it
certainly would explain why so many American ferrets get the disease. But
then, it doesn't explain why so many American ferrets do NOT get the disease
nor why it is so unpredictible. Like cancer, it seems to run in families,
but you cannot predict which ferret will or will not get adrenal disease.
Which is exactly why I think an environmental trigger is also necessary for
the disease to show itself.
I have chosen to assume the genetics are about the same between American
ferrets and all others. That is because the intital ferret population in
the Americas was so high that a founder's effect or genetic drift becomes
improbable. Not impossible, but not very likely either. While I doubt if
the America population a century ago rivaled that in Great Britain, it had
to equal or exceed those populations in New Zealand and Australia, and guess
what? Those ferrets are weaned on environmental conditions similar to those
in Britain, and they have similar adrenal disease rates. Assuming the USA
has vets better able to diagnose or identify the disease is both
nationalistically arrogant and well as unsupported by facts. Did you ever
think the reason American vets know more about the disease is because it
occurs at rates unnaturally high here? Or that the reason some of reports
starting to surface elsewhere might be because American ferret environments
are becoming more common?
The trouble is, if this is true, (and at best it is only a working
hypothesis), what are the environmental triggers? Either the genetics of
the American ferrets and all others are different, or they are about the
same. You must assume they are the same UNTIL you can prove otherwise. If
they are the same, then some environmental factor must be behind the
outbreaks. Since there are a number of environmental differences, ranging
from photoperiods to diet to a virus to stress to early neutering, and not a
single study has looked into THESE issues, then at this point in time the
issue is too complex to resolve. Its that simple. Infinite causes and a
finite effect.
Still, much can be learned if we set aside our prejudices and take a careful
look into what is the same between the Americas and Europe, and what is
different, because therein lies the answer to the environmental trigger,
should one exist. Like links in a chain, it may be possible break a link
and prevent the disease from occurring. Sort of like the identical twin
smoking study done some time ago. One twin smoked, the other did not. In
those cases where the twins had a genetic predisposition towards cancer, the
smoker got lung cancer. Smoking was the environmental trigger, and breaking
the link--smoking--reduced the chances of lung cancer significantly. Don't
buy the comparison? Do you remember what adrenal disease is? A tumorous
growth in the adrenal gland? So what is lung cancer? I'm not implying they
are the same disease--and in fact they are quite differen--but just like
comparing a TR-3 to a VW bug, they might be different, but much of the
mechanisms is similar. They are inherently comparable.
Of all the possible environmental triggers, the most plausible are some sort
of biological agent, like a virus or bacteria, stress, early neutering, diet
or some combination of these. Photoperiodism might be a contributing case,
but since other animals that are as subject to photoperiodism as ferrets, or
more, do not exhibit problems, I discount its contribution. An unknown
biological agent is certainly a viable option, but little is known of their
relative effects in tumor growth. Im afraid the major environmental
differences between American and all other ferrets must lie in diet, stress
and early neutering, or some combination.
Early neutering does not seem to be a problem with other species, so it
loses some of its credability in the ferret issue. Still, dogs and cats are
not typically neutered at the same relative stage of growth as many ferrets,
expecially those neutered at about a month of age. This is because the
growth curves of the various species are different, so one being neutered at
6 weeks might be the physiological equal to another species being neutered
at 3 weeks. I know of no research into this issue.
Diet can also be an important factor. Adrenal disease really didn't start
making headway in the Americas until after kibble became a popular food.
It is quite possible that the lack of a micronutrient could be causing a
physiological problem resulting in the disease. Convinced kibble is a
perfect food? I have three references, none more than 5 years old, that
suggest "any kibbled food is an approximation of a natural diet and as such
cannot supply the diet the [predator] consumed during its evolution." I
have had so many requests that I address the diet issue that I will drop it
for now in favor of a future post. Still, as a trigger in adrenal disease?
I have some doubts.
That leaves stress. Some human research suggests there is "good" stress and
there is "bad" stress. Good stress are those events that either strengthen
or condition your body towards some event, such as a sporting event or
asking someone out on a date. Bad stress is of the type that is not quickly
resolved, like school or work stress, and is thought to be a factor in
human heart disease. While I was able to find lots of info regarding
maternal-separation stress in lots of different animals, little has been
done with ferrets, and nothing looking into the possible link between stress
and adrenal disease. Stress is a natural suspect, because it is so
intimately involved with the adrenal gland itself. It may well be that
unresolved stress might be the triggering mechanism, and early maternal
separation, close (unresolved) shelter contact with unknown or strange
ferrets, or lack of physical contact be factors as important or more than
genetics or early neutering.
Of course, it could be a combination of those (or others) that is trigging
adrenal disease. For example, maybe a MF ferret was early separated, early
neutered, then shipped to a pet store having a completely new environment,
all full of stress. Feed a kibbled diet which could possible cause some
physiological stress, the combinations of all the different stresses trigger
the growth of a small tumor in the left adrenal. This is just a story, but
it is a testable idea.
Complicating the entire argument is the observation that adrenal disease
seems to be exhibited in two different manners; one a late onset, and the
other is an early onset with often a later recurrence. I cannot distinquish
this from being two different diseases, one disease that exhibits
differently, or just random happenstance. I know of no study into this
issue.
As for treatment, surgery is the only treatment that has any long term
benefit for the ferret. As already discussed in the 1st post, drug or
chemical treaments do not offer a significant difference in life span
compared to no treatment at all. They do provide the ferret with perhaps
a slightly higher quality of life during that time, but no real increase in
lifespan. It is better to be aggressive and remove the tumor as soon as
possible, because the disease gradually weakens the ferret and increases
the chances of complications. The younger the ferret, the petter the
prognosis, although the younger the ferret, the more likely a second
adrenal tumor will crop up.
I don't see an easy resolution to this problem. It requires money,
intelligent and dedicated people looking into the issues, and time. Genetic
and environmental factors need to be ruled out, ferret *will* die to resolve
this, that you can be sure. Can we help? Hell yes!
The best way each of us can help is with GOOD records on each and every one
of your carpet sharks. As much of the lineage as possible, estimated birth
date, diet (including manufacturer of diet), shot record, weekly
temperatures and weights, record of treats, social interactions, etc. We
can be like Tyco Brahe, who painstakingly measured the distances (time)
between stars, knowing there was no reall good purpose for the data. Yet,
that same data, in the hands of Kepler and Newton, rewrote our history. We
can create the data that some smart whipper-snapper down the road can take
and solve the problem. I suggest those people who currently are on the
adrenal mailing list, work with some quasi-national club to create a
scientifically correct adrenal data base, gather info from vets, breeders
and owners, and provide it to bonafide researchers. We already have the
answers; we just need it in an unbiased and correct form of data.
So that's it. I recommend you go back and read the preceding four posts (or
just skim them) before firing off a question just to remind yourself of what
had been said already. I have tried very hard not to offend anyone position
or platform. Not really, I've tried hard to offend them all. I have my
asbestos lonhjohns on, my trusty data base in one hand, and Carbone, just
starting his first rut, in the other. I'm ready.
Bob C and the 20 MO Ferrets just relieved its all over.
[Posted in FML issue 2234]
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