Q: "...I read [in the FML, FHL] about all kinds of reactions and deaths
    from vaccinations.  Arena't they too dangerous [to use]?"
 
A: Absolutely!  Reading about health risks on either mailing list is
   very dangerous--it makes ferret owners crazy!
 
Ferret lists ALWAYS over-report disease when compared to the population
as a whole.  It is sort of like reading a veterinary journal; you only
read about diseases, not about happy, healthy animals.  Also, most
diseases reported are those at the end of a ferret's natural life, which
makes them appear to have more importance than they deserve.  Think about
it; you have to die of SOMETHING!  In ferrets, diseases of old age include
various cancers and heart disease.  Ferrets are only biologically designed
to live about five years, and MOST diseases start kicking in about then,
as the body loses its ability to ward off disease or fix mistakes in DNA.
 
The same over-reporting of problems is true regarding ferret vaccinations.
Vaccinations are essentially harmless UNLESS a bad reaction takes place.
There are a number of people who believe inoculations cause long term
health problems, but data supporting that position is meager (besides,
other than a vaccination NOT resulting in a full-blown disease, how is
being inoculated for canine distemper by injection different than catching
it from a neighbor's dog?  The reaction of the body is virtually
identical, which is why vaccinations work, and polio and smallpox is no
longer the public health problem they were just 40 years ago).  The real
problem is the ferret can form an allergy to various proteins in the
inoculation, causing a systemic allergic reaction that results in the
ferret going into shock.
 
In terms of anaphylactic shock, what is the risk factor for ferrets to
be vaccinated against canine distemper?  Risk is defined as the number
of occurrences per number of trials; if out of 10,000 vaccinations, one
ferret had a bad reaction, then the risk of a bad reaction would be
1/10,000.  Now, out of all the bad reactions, how many result in death?
One out of hundred?  If that is the case, then you can expect one ferret
out of 100,000 ferrets vaccinated to die from inoculation complications.
Is this a fair assessment?  Probably not; virtually ALL ferrets have been
inoculated against canine distemper prior to sale, large ferret farm and
hobby breeder alike.  These vaccinations are repeated for a large majority
of these ferrets at least a couple of times during their lives.  Yet, each
year, only a handful of ferrets die after receiving a distemper shot.
 
We do have a problem; the numbers discussed above are imaginary.  We don't
know the actual number of ferrets that live in the USA, how many are
vaccinated, how many have bad reactions, and how many die.  I have NO way
to prove or disprove the actual risk without first having actual numbers.
BUT, we can sneak around the problem by looking at a smaller population
of ferrets--those who have owners that post on the FHL and FML.
 
After an extensive search on the FML and FHL archives (I burn the archives
to CD for ease of search), I have found the risk of reaction (of any
type) to canine distemper vaccine to be about 1/100 (assuming those not
reporting anything as not having reactions), and death from vaccination to
be roughly 1/35 of the reactive group.  In other words, of the instances
reported in the two archives, about one of a hundred inoculations result
in a reaction, and one out of thirty-five reactions result in death.  If
we work backwards, we might be able to come up with a rough assessment of
relative risk for the population as a whole.  Assume the total population
of ferrets in the US is about 4 million (a fair guess).  We know virtually
ALL ferrets have been vaccinated prior to sale at a young age, so we can
assume the entire population of ferrets in the USA has been vaccinated at
least once in their lives.  Using the FML and FHL archives, an average
of five ferrets are reported to having died per year.  This number is
over-reported because health problems as a whole are over-reported in FML
and FHL archives, but that's ok to make a worst-case guess, if we realize
the actual numbers are smaller.  During the time period of the archives,
let's make an assumption that the average number of people on the lists
number 4000, each owning about four ferrets.  Again, actual numbers are
much smaller; I have picked numbers I KNOW are larger than in real life
so I can control the location of error even though I can't control the
degree of error.
 
Here's the math: 4000 people owning four ferrets each is a population
of 16,000 ferrets.  Since, on the same lists, the rate of reaction to
vaccination was reported to be about 1/100, we can expect about 160 bad
reactions per year.  Of those bad reactions, with a death rate of 1/35,
we can expect about 4 to 5 deaths per year.  Since this extrapolated
number is about the same as the actual reported number of deaths, even if
our assumptions are wrong, they don't change the outcome.
 
Extrapolating to the ferret population in the USA, assumed at about 4
million, which means we can expect 40,000 bad reactions, resulting in
1143 deaths.  See why I said the FML and FHL over-reports specific health
problems?  If 1143 ferrets died per year from bad reactions from
vaccinations, the vaccine would be pulled from the market!  I can't tell
you how many ferrets die per year from reactions to canine distemper
vaccine, but it is nowhere near 1143 ferrets!  Nationally, the number is
somewhere between 20 to 30, or so (based on reaction rates published in
the vaccine literature and estimated ferret populations, as well as
reports in reviewed literature).
 
This is a tremendous rate of error, illustrating the mistake of using
ferret lists as a guide to the health problems of ferrets.  In fact, my
estimate is artificially low because I assumed larger numbers of people
reading the lists, for longer periods of time.  If real numbers were used,
the final US estimate would exceed 2000 ferrets dying annually from canine
distemper vaccinations--100 times more than the actual numbers.
 
That is NOT to say there isn't value to be gained from looking at FML and
FHL lists, if you discard the numerical values and concentrate of relative
values instead.  For example, while adrenal and pancreatic disease are
over-reported compared to the population as a whole, the reports of one
compared to the other are proportionally correct.  In other words, even
though adrenal disease is over-reported, the relative reports of adrenal
disease is proportional to its occurrence in the overall population.  For
example (and these are imaginary numbers used to illustrate the example),
if people report 100 instances of adrenal disease and 25 instances of
pancreatic disease, while both numbers may be erroneous compared to the
actual disease rate of the ferret population, relative to each other, the
4:1 proportion MAY be correct.
 
So, if you base your objections to vaccinating your ferret based on
problems listed in ferret lists, you are making a serious mistake.  Why?
Because while the risk of reaction to canine distemper MAY be as high as
1/100, with 1 out of 35 dying (as reported on ferret lists; the actual
numbers are MUCH lower), the chance of a ferret living through canine
distemper is nearly zero.  In other words, the risks of death by distemper
greatly outweigh the risks of reaction and death caused by vaccination
reactions.
 
The bottom line is that while ferret lists are wonderful places for
getting help, receiving support, and finding answers, they are terrible
places to shop for data to show disease or vaccination reaction rates.
These numbers are ALWAYS vastly over-reported, leaving people with the
impression that ferrets always get adrenal disease, languish from
cardiomyopathy, suffer from low blood sugar, and die from canine distemper
vaccinations.  In truth, the risk of a ferret having a reaction from a
canine distemper vaccination is roughly proportional to a human having a
reaction to a vaccination for measles.  Considering the risks of NOT
vaccinating for canine distemper, the risks of reaction are well worth
it.  As for the risks of ferrets being "poisoned" by vaccinations?  Well,
perhaps there is a problem that is yet to be investigated and reported.
Considering other environmental risks faced by ferrets, including
breathing second-hand smoke, being killed by recliners, or in washers,
dryers, and dishwashers, and even just being stepped on, I figure the
risk from vaccination to be acceptable.  And IF you have ever seen a
ferret suffer a horrible, lingering death from canine distemper, you
would probably agree.
 
Bob C
[Posted in FML issue 3779]