SheltieChe
Forums Sage
it really does not matter new or old vaccine, principles of immunology are still the same.
"vaccinating a lyme positive dog
think about it
Conundrum
So you ask yourself: If a Snap3DX test comes back positive for Lyme disease, should my dog be vaccinated against Lyme after he's been treated?
Evidently, some vets consider this an accepted protocol and the rationale for following it seems to be that by giving the vaccination after treatment, you ensure that antibodies in the vaccine will start fighting Lyme disease right away.
This is a protocol advanced by Dr.Stephen Levy, a veterinarian whose name has appeared as author or co-author on several papers dealing with canine Lyme vaccination, testing, and/or treatment, and who practices in Durham, CT, a town in the "hot zone" for Lyme disease.
Most of the other experts on canine Lyme don't appear to agree with Dr. Levy, however. So, why does he believe what he does?
A year or so ago, Dr. Tom Beckett explained it this way for those of us who need it kept simple.
"To understand the rationale posited for vaccinating Lyme seropositive
dogs--indeed, any dog--we need to start with some ABC's of immunology and move through some peculiarities of Lyme immunology.
"First of all, an antigen (Ag) is a substance--generally a protein--that
causes immune system cells to produce an antibody (Ab), which is also a protein. An Ag and its corresponding Ab are very specific to each
other--they are capable of fitting/bonding together in a manner likened to a the matchup of a lock and key.
"Sequences of nucleic acid bases in a microbes DNA govern what
proteins/antigens the microbe produces by specifying what amino acids are put together and how they are assembled.
"Some microbes--notably Borrelia burgdorferi (Bb)--contain in their DNA some alternate DNA sequences which they can activate or deactivate and thereby vary the proteins/antigens which they produce. This variation mechanism is triggered mainly by the environmental conditions the microbe encounters.
"For example, Bb produces the protein/antigen that the c6 peptide mimics when it is growing in a mammal, but not when it is in a tick or a culture flask.
"Conversely, Bb liberally produces a protein/antigen called OspA when in a tick or a culture flask, but as it moves into a mammal Bb switches off OspA production and only resumes production of very scarce amounts of OspA after a very long-standing infection in the mammal, if then.
"Now, we are ready for the conceptual model that underlies all vaccination
for Lyme. We have these ticks which harbor Bb. The Bb they harbor are cranking out OspA and are therefore covered with OpsA antigen.
"If we inoculate the dog with a vaccine containing OpsA antigen, the dog will produce OpsA antibody.
"When a tick begins to feed on the vaccinated dog, the blood meal will wash over the Bb, bathing them in dog blood loaded with OspA antibody. The OspA antibody will latch onto the OspA antigen on the Bb, and this will mark the Bb for destruction before it can infect the dog.
"It is a beautiful concept, and there is some data indicating it actually
works about 80% of the time in dogs naive (new) to Lyme exposure. (BTW, Dr. Levy was a main player in one of the larger studies that produced this data.)
"Now we get down to the rationale posited for vaccinating seropositive dogs and even symptomatic dogs that are responding to antibiotics.
"Remember we said Bb produces essentially no OspA antigen while in the dog. Therefore a non-vaccinated dog will produce no OspA antibody because its immune cells have not "seen" any OspA antigen. Thus the non-vaccinated dog has no OspA Ag/Ab mechanism to kill Bb as they emerge from infected ticks. Therefore Bb from new tick bites are free to move on into the dog as a re-infection or super-infection.
"On the other hand--the rationale goes--if we vaccinate the dog we can bring the OspA Ag/Ab mechanism into play and drastically curtail the chances of re-infection or super-infection.
"Many veterinary Lyme gurus, however, have strong doubts (at the least) about Lyme vaccination generally and are even less sanguine about the notion of vaccinating seropositive/symptomatic dogs. It is certainly incorrect to label the practice as an "accepted" protocol.
"Among the unanswered questions about the Levy protocol:
-- Does it actually work?
-- Is it necessary?
-- Is it safe or does it add to the Ag/Ab load potentially able to produce
pathology through immune-complex disease?
"No firm class 1 evidence seems to exist that would help answer the
questions."
