Coonhound Paralysis
Coonhound Paralysis (also called acute idiopathic
polyradiculoneuritis) is one of those neuropathies
(neurological pathologies) of undetermined origin. It is an
auto immune reaction, an immune mediated inflammation of
nerves and nerve roots. It occurs when a dog previously
sensitized ("allergic") to certain antigens, most commonly a
protein in raccoon saliva, develops an immune reaction to
the antigen. It seems to follow having been bitten by a
raccoon, and seems to affect only dogs. It does NOT affect
ALL dogs thus savaged by raccoons, nor does it seem to
affect cats or raccoons similarly afflicted.
The scenario goes as follows. A few days after having
been bitten, the dog begins to be weak on the hind end and
gradually becomes more and more paralyzed, eventually losing
control of bladder, and in some cases, of breathing.
Fatalities are rare, but known. Severe cases can result in
death from respiratory paralysis. This immune system
reaction attacks portions of the peripheral nerves, causing
rapidly progressing flaccid paralysis. If you can give
supportive care for long enough, the dog gets better,
usually within 4-6 weeks. There is no recommended
"treatment" (antibiotic therapy) that works. Coonhound
paralysis resembles tick paralysis. Affected dogs are at
increased risk of future attacks if exposed again to raccoon
saliva, since they are not sensitized to the antigen.
No toxins have ever been isolated from raccoon saliva,
nor have micro-organisms been found that would account for
it. It is generally considered to be an immune reaction to
some protein in the saliva, which attacks the dog's own
neural tissue.
The worst part is that raccoons are well know to carry
and suffer from rabies. The symptoms of rabies are sometimes
similar and incubation of rabies can be extremely short. How
to differentiated between the two? A paired serum samples
showing a steeply rising titre against rabies would be
sufficient.
This disease is almost identical to Guillain Barre (aka
John Barry) syndrome in humans.
Source: Hugh Baker, DVM (Ontario, Canada); Tracy Hammer,
DVM (College of Vet Medicine MSU); W.B. Thomas, DVM
(Neurologist, University of Tennessee) |
