Bob said,
>In the majority of cases, these diseases become a problem when the ferret
>is between 4 and 6 years of age and invariably are the ultimate cause of
>death.
 
Sukie said,
>Bob, I have to disagree with the "invariably" part.
 
So, the blond lady from Jersey (whom I have STILL never met) wants a fight,
eh?  Come on, I'll fight you!  Put 'em up!  Owwwww!  No fair going for the
belly!  Steve!  Help me!  Steve!  Steve!  .....Coward....
 
Actually, my statement was poorly worded and I'm glad you pointed out the
misunderstanding it might cause.  It is clearly to imprecise to be of much
value, especially as a general statement.  I should have done better.
Sorry.
 
I have two comments.  First, if a person has Aids and dies of pneumonia,
what is the cause of death?  Aids or pneumonia?  The way I see it,
pneumonia is the proximal cause of death, and Aids the causative agent of
death.  I know it is a nitpicking way of looking at things, sort of like
saying it wasn't the criminal who killed the storekeeper, but the bullet
that pierced their heart.  Clearly, a person without Aids is at low risk of
dying of certain pneumonias, so it is a fair characterization to say the
person contracted the pneumonia and died BECAUSE of their Aids infection.
In the Aids example, the person DIED of pneumonia, not Aids, but the
pneumonia was only able to kill because of the physiological conditions
caused by the other disease.  This is a common occurrence in age-related
diseases where one battery of diseases make the ferret vulnerable to many
others, which are often terminal.  Not always, of course, but often.
 
My original statement was intended to be viewed in this light; that
diseases of old age are the ultimate (or the causative) agent of death,
but not necessarily the proximal cause of death.  My original wording was
poorly done and left room for misunderstanding.
 
The other comment is concerns the diseases I mentioned, cancers of the
pancreas and adrenals.  These are by no means the ONLY disease of age in
ferrets, just some examples I mentioned to show the point.  Old age
diseases are about the same form species to species; in other words,
older individuals of ALL mammalian species tend to die from cancers,
cardiovascular disease, kidney and liver problems, etc.  The diseases are
the same, but the RELATIVE FREQUENCY of those diseases vary from species
to species.  So, humans might have a higher incidence of cardiovascular
disease compared to ferrets, who might have a higher incidence of endocrine
disorders compared to goats.  The evolutionary history of the particular
species, as reflected in their genetics, is one major factor in the
determination of relative frequency of old age diseases.  Another major
factor is the lifetime accumulated environmental risk each individual has
going against them.
 
That is what I think is going on with ferrets and certain cancers.  I think
the evolutionary history of the ferret has left them vulnerable to specific
types of cancers, but it is the environmental risks associated with the
ferret that ultimately cause the outbreak of disease (in the MAJORITY of
cases).  I think, like with humans and all other mammals, these problems
are exacerbated by age.  So, the ultimate reason older ferrets may contract
certain cancers may have little to do with who bred it, and more to do with
a genetic disposition, lifetime environmental risk, and simple old age.
 
This combination of factors is extremely complex, rendering prediction
of disease nearly impossible.  One ferret might have the genetic
predisposition, but never experience significant environmental risk.
Another ferret may have the environmental risks, but is not genetically
at risk.  This is the reason why certain diseases show up more in older
ferrets; the older they are, the more lifetime environmental risk they
accumulate.  Throw the dice long enough and you will eventually crap out.
Without knowing the exact risks accumulated, the exact genetic
predisposition, and the age of the ferret, you will never be able to
accurately predict disease risk and longevity.  So we end up using
qualifying statements, like "many," "the majority," "in general," and my
personal favorite, "a significant number." Weasel words to be sure, but
they illustrate the difficulty of predicting biological outcomes.
 
The bottom line is that ferrets live in bodies that were genetically
engineered (via evolutionary processes) to last two to three years, and
they are living, as pets, double, triple, even quadruple that length of
time.  Interestingly enough, the same is true for humans, and,
proportionally, by about the same amount.  It is no wonder that similar
types of diseases; i.e. cancers, heart disease, etc., kill both species as
we get past our engineered specs.  And while the specific nature of those
diseases are essentially due to historical accident (the combination of
genetics and environment), the fact is, the older you get, the more common
they become.  And THAT is what I meant when I said diseases of old age are
"invariably are the ultimate cause of death." Even if they aren't typically
seen as the proximal cause of death, they often influence the morbidity of
other diseases, turning typically survivable diseases into fatal ones.
 
Sorry for my lack of precision in the earlier post.  I'll do better when
the swirling colors fade.
 
Bob C and 16 MO' Imprecise Imps
[Posted in FML issue 2969]