There have have a variety of posts on distemper and rabies vaccination so
this is in response to multiple comments in the past few days.
 
Debbie Riccio mentioned the importance of yearly distemper boosters.
Actually, it's not known if ferrets really need them annually.  Due to the
economics of the drug and vaccine industry, a manufacturer will pay to do
the studies needed to get a product approved, but usually will not spend
additional money to study whether the same drug or vaccine can be used at a
lower dose or less frequently.  It's against their economic interest to do
so, and such studies are usually done by med/vet schools or funded by
government agencies such as NIH, FDA or USDA.  Fervac-D is an attenuated
live virus, most of which are very good at producing a strong immune
response.  It's entirely possible that Fervac produces sufficient immunity
to allow boosters every two or three years.  United Vaccines isn't going to
spend tens or hundreds of thousands of dollars to do a study that would
result in ferrets owners using their product less.  (Substitute "millions"
for "thousands" in the case of human diseases.) Until we know better, the
safest course is to vaccinate annually, but it would be nice to be able to
do it less frequently.  Anyone in the vet schools want to write up a grant
proposal to USDA to study a less-frequent regimen of distemper boosters?
 
BTW, some veterinary vaccines are now given nasally, and I'd wager that an
intranasally administered form of Fervac would work better than the IM dose
currently approved.  One conversation I had with United Vaccines indicated
they are interested in this approach.  If they happen to study it for minks,
they may extend/duplicate the study to include ferrets.  Stay tuned.
(Fervac was developed initially for use in minks.)
 
One comment suggested that young animals lose the ability to absorb
antibodies from the mother shortly after birth and questioned whether late
weaning provided extended protection against infection in the kits.  Even if
the ability to absorb antibodies wanes in the kits, the jill still produces
IgA in her milk.  This form of antibody is naturally produced in the gut and
helps protects against infections through the GI tract, so there *may* be
some residual benefit from late weaning.  I haven't seen that it's been
studied in ferets, though.  It should also be noted that the amount of
antibodies passed to babies is also affected by the timing of the mother's
last vaccinations.  Mothers vaccinated just before being bred or during
pregnancy pass more antibodies (both IgG and IgA) and have a higher antibody
count than mothers vaccinated months earlier.
 
I believe Bill Killian asked about transmission of rabies in utero.  I have
also seen that paper but I don't have a copy of it.  The paper basically
showed that rabies could be transmitted to skunk kits.  I don't remember if
the transmission occurred through the placenta or at birth.  Rabies should
not be transmissable through breast milk at all.  Placental transmission of
rabies seems very unlikely given that rabies infects nerves and there is no
connection between a mother's nervous system and a fetus.  I'm not certain
if rabies could be transmitted at birth.  That happens with HIV, herpes and
other viruses that infect babies of infected mothers.  However, rabies
travels from the site of a bite, up the afferent nerves to the brain.  It
should have no reason to take a detour to the uterus or cervix.  So, I'm
stumped.  Transmission from mother to kit should *not* happen given the way
rabies behaves.  If I find the skunk paper, I can report back.  In any
event, I doubt it can be used as a valid argument to kill & test ferret kits
since from all existing studies, rabies-infected jills wouldn't live long
enough to give birth to or rear the kits.
 
That's why we're all in shock here in North Carolina after the state vet
euthanized a pet store kit that bit a girl.  The kit had come directly from
the breeder, never been exposed to another animal in the store (except
people, of course) and could not have been exposed to rabies.  Our local
ferret group, TriFL is trying to find a sufficient way to chastise the state
vet, Dr. Lee Hunter.  I find it hard to defend the actions of public health
officials when they disregard scientific and medical reason.
 
   --Jeff Johnston ([log in to unmask])
[Posted in FML issue 1616]