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From: Bob Church
rrc961@MIZZOU.EDU
Q: "Bob! At the Ferrets 2000 offical pub, you mentioned you
thought the next big plague to hit ferrets would be Aleutians
Disease. The very next day, I heard Dr. Williams speak about
it and I am now quite scared. Is it as bad as you think?"
A: I think therefore I am, and I am convinced it is the
ferret's version of AIDS.
I cannot and will not address the veterinary aspect of this
question because a) I am not well read on this disease,
and b) I am not qualified because I am not a vet.
But I have extensively studied the effects of introduced
disease into virgin animal populations, giving several papers
and recently being asked to write a book chapter on the
subject. So, from an evolutionary aspect, I think I can
discuss a few things. Still, I will forward a copy of this
reply to Dr. Williams in the hope he can better address the
issue. If I were you (assuming he elects to reply), I would
listen carefully to him and treat it as gospel. That is not
just because the man in extremely intelligent, but also
because he is an excellent pathologist and probably knows
this subject better than most vets (I know he seriously
impressed me, and I --for one-- am EXTREMELY pleased he has
started posting so frequently on the FML!!! We are extremely
fortunate!)
ADV (or Aleutian Disease Virus; aka Aleutian Island Disease)
is a parvovirus which evolved in mink (Mustela vison), and to
which they have more or less adapted. By this I mean the
disease is not always fatal; some cases are very mild, some
are deadly, but most are in that region of middle ground
where it can become a serious problem if the mink is weak or
stressed, but not usually fatal. This is a coevolutionary
adaptation between the pathogen (the ADV virus) and the host
(the mink); those strains of the virus which are especially
nasty kill off the hosts and reduce their chances of being
spread. Those mink who are more resistant to the disease
survive and pass on the immunity to their offspring. The end
result is, over a remarkably short number of generations, the
disease becomes less deadly and the hosts become more
resistant. Take measles for example; it is a mutated variant
of the same type of virus which causes both rinderpest and
canine distemper. When it first spread in Europe, people died
by the thousands. Over a few generations, it became a
serious, yet not necessarily deadly disease. Until Europeans
floated to the New World, and found a virgin population; that
is, a population never exposed to the disease. Tens of
thousands of Native Americans were doomed. Now days, few
people, including Native Americans, die from measles.
Coevolution between host and disease has taken place;
evolution in our time.
Mink and ferrets are kissing cousins in Weasel World. Because
some fur ranches housed both ferrets AND mink, it was just a
matter of time for a chance mutation to allow the virus to
cross the species line. Like in the measles example, the
disease is usually quite nasty in a virgin population
(ferrets) and ultimately results in death. But that's not the
problem as I see it. To me, ADV is very much like AIDS in
that
1) it has a very long incubation period before it is
expressed,
2) in ferrets, it is almost always fatal,
3) casual contact can spread the disease,
4) as viruses go, it is not especially hardy,
5) they are both immune system diseases and
6) there is NO cure.
The first reason is really the one which scares the crap out
of me. Unlike ECE, where the ferret contracted the disease
rapidly after exposure, it can take years for ADV to be
expressed, and by the time you realize your little bundle of
dancing fur is sick, your entire house could have contracted
the disease, dooming all.
The other thing about ADV which scares me is when the
symptoms start being expressed, they can easily be
misdiagnosed as a non-specific wasting disease, insulinoma,
cardiomyopathy, renal disease and a host of other deadly
things. It is possible many cases of ADV have been (and will
be) misdiagnosed, and animals which are spreading the disease
are still coming into contact with healthy ferrets. So, like
when AIDS first hit in the USA, it can take a long time for
the full extent of the disease to be known.
ADV, like the initial cases of ECE, is already spreading into
the ferret population like a virgin ground disease. The
effects are easily predictable; at first the disease will
kill a tremendous number of ferrets, but ultimately, it will
either burn itself out (doubtful) or both the disease and
ferrets will coadapt. These are predictable results, but the
problem is the large number of ferrets which will die before
the predictions hold true. I don't want my guys to be a part
of that statistic.
This may sound a bit like hyperbole, and perhaps it is; as I
said, I am not a vet. However, if I am correct and this
disease follows the same sort of pattern as any number of
virgin ground diseases, including plague, distemper, ECE,
AIDS, measles, smallpox, and many, many others, then you can
expect that what you observed with ECE will also occur with
ADV. I think it will be the next ferret plague, and in years
to come, thousands of ferrets will be suffering as a result.
I am sure Dr. Williams can easily explain this better than I,
and fervently beg him to do so, perhaps also offering public
heath advice in preventing exposure.
Bob C and 15 Mo' Virgin Ground Ferrets

White Russian's Mom's ADV Web-Site Pages
Other ADV Web-Site Pages
And for some history and a look further:

Wolfy...wolfysluv@AOL.COM
