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Vaccination:
Part II
Which ones do they
REALLY NEED, and HOW OFTEN?
by
Ann Brightman
A 3 part article published in Animal
Wellness Magazine
Volume 7 Issue 3. Publishing date:
May 17, 2005 |
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Monica’s
Siamese cat, Sapphire, was five years
old when he developed an autoimmune
disorder that she learned had been
triggered by too many vaccines. “I
was shocked,” says Monica. “I’d
always been told pets had to have
shots every year, so that’s
what I was doing.” A talk with
a holistic vet, along with some research,
soon enlightened Monica about the
dangers of overvaccination. “From
now on, I’m sticking to the
core vaccines for my kittens, and
opting for titer testing rather than
annual shots,” she says. “It’s
too late to cure Sapphire, but at
least I can help protect him and my
future cats from further problems.”
Unfortunately, a lot of people don’t
learn about the negative effects of
overvaccination until their dog or
cat gets sick. Conditions that have
been linked to too many vaccines include
immune and nervous system diseases
as well as allergies, kidney, liver
and digestive disorders and a host
of other problems. The good news is
that more and more animal guardians
and veterinarians are coming around
to the fact that annual vaccinations
are not only undesirable but unnecessary,
and that many of the vaccines given
to dogs and cats, apart from the essential
core vaccines, aren’t really
even needed. Guidelines from the American
Animal Hospital Association (AAHA)
and the American Association of Feline
Practitioners (AAFP) now recommend
that core vaccines be given only once
every three years instead of annually.
In fact, durations of immunity ranging
from seven to nine years have been
demonstrated for all the core vaccinations,
except for rabies, which indicates
that even three-year vaccines aren’t
necessary in most cases.
Core vaccines are those that are considered
essential, and include rabies (required
by law), canine distemper and feline
panleukopenia (covered in Volume 7,
Issue 2), as well as parvovirus-2
and canine adenovirus-2 for dogs,
and feline herpesvirus-1 and feline
calicivirus for cats. In this issue,
part two in a series of three, we’ll
take a close-up look at canine parvovirus-2
and feline herpesvirus-1.
CANINE PARVOVIRUS-2 (CPV-2)
An extremely contagious viral disease,
CPV-2 is almost identical to the virus
that causes feline panleukopenia (also
called feline parvo). “Parvovirus
only entered the canine species in
1978,” says Dr. Ron Schultz
of the University of Wisconsin-Madison’s
School of Veterinary Medicine. At
the time, the breeds most susceptible
to the disease were Dobermans and
Rottweilers. “In the early 1980s,
I found that a lot of Rottweilers
and Dobermans were unable to respond
to the canine parvo vaccines,”
says Dr. Schultz. “Since then,
natural selection has eliminated most
of the genetics that were predisposing
these breeds to parvo. Today, I find
no more non-responders among Rottweilers
and Dobermans than I do among Labs
or beagles.” The virus itself
has also undergone several mutations
over the last 30 years. “The
initial canine parvovirus was genotype
2. The next one to come along about
four years later was 2A, and two years
after that was 2B. Today, the only
one in the environment is 2B, although
vaccines made to 2, 2A and 2B are
equally effective in controlling canine
parvo.”
CPV-2 attacks the intestinal tract,
causing vomiting and diarrhea, as
well as fever, depression, dehydration
and frequently death. It is spread
not only by direct contact, but also
by the hair, feet and feces of infected
dogs. Because it’s an extremely
hardy and resistant virus, it can
stay alive in the environment for
months, continuing to pose a threat
long after the sick animal has gone.
Like many infectious diseases, CPV-2
is strongly age related, and most
often affects young animals. Mortality
rates among puppies under a year old
can reach 100%, but this figure drops
dramatically as the dog matures. “If
the dog escapes parvo infection in
his first year, he could get infected
later and would develop natural immunity,”
says Dr. Schultz. “I don’t
often see mortality in dogs over a
year old.”
It’s because parvo is such a
dangerous disease for puppies that
the CPV-2 vaccine is counted as one
of the cores. “I don’t
think there’s a dog alive that
shouldn’t have had a parvo,
distemper, adeno-2 and rabies vaccination,”
says Dr. Schultz. As serious as parvo
is, however, it isn’t necessary
to vaccinate your dog every year,
providing a modified live vaccine
(MLV) is used. Killed vaccines are
much less effective, and in fact AAHA
recommends annual re-vaccination for
killed CPV-2 vaccines, unless they
are used as boosters after an initial
series of live vaccines, in which
case every three years is recommended.
For MLV-CPV-2, studies show the duration
of immunity is seven to nine years,
which is nearly a lifetime in some
cases. “The MLV vaccines are
very effective, especially for parvo
and adenovirus, and they can protect
the dog for a heck of a long time,”
says Dr. Schultz. “I believe
dogs really only need to receive the
core vaccines once, and that’s
at an age when they can respond to
them, and when the passive maternal
antibodies won’t prevent active
immunization (at or over 12 weeks
of age). After that, they never need
to have them again. Titer testing
is also highly effective for parvo.”
FELINE HERPESVIRUS-1 (FHV-1)
Along with feline calicivirus, FHV-1
(also referred to as feline rhinotracheitis)
is the most common upper respiratory
infection in cats. It’s found
worldwide, and because it’s
so contagious, the risk of exposure
is high. FHV-1 can be spread in one
of three ways: by direct contact,
through the air when an infected cat
sneezes, and from contaminated surfaces.
Although the virus doesn’t live
very long in the environment, especially
in sunlight, it can survive for many
hours in moist, cool areas, and may
last long enough on dishes or litter
trays to infect other cats. It’s
important to recognize that while
humans can also get herpes, FHV-1
is specific to cats and can’t
be transmitted to people.
Feline herpesvirus-1 primarily affects
the nose, eyes and throat. The first
tell-tale symptom is sneezing, followed
by fever, loss of appetite, depression,
and a mucousy discharge from the nose
and eyes. The cat may also develop
conjunctivitis, in which the white
part surrounding the eye becomes inflamed.
In severe cases, eye and mouth ulcers
may form.
Kittens are more seriously affected
than adult cats and can often die
from the disease. They can be infected
at a very young age, even before birth
if the mother cat has the virus in
her system. Adult cats are also susceptible,
but the disease is rarely fatal except
in cases where the cat’s immune
system is compromised.
In most cases, FHV-1 is self-limiting,
which means cats with strong immunity
can successfully overcome the infection.
However, most cats who have had FHV-1
become lifelong carriers of the disease.
Although they remain latent most of
the time, an episode of stress or
the administration of corticosteroids
can reactivate the disease, causing
mild symptoms and virus shedding that
can infect other cats.
The FHV-1 vaccine is available in
both MLV and killed forms. Also offered
is a topical (intranasal or conjunctival)
MLV vaccine, which may be given to
kittens as young as ten days in situations
where the disease is endemic (for
example, in some shelters or
catteries). However, FHV-1 vaccines
are not as effective as most of the
other cores and, according to AAFP’s
Feline Vaccination Guidelines, offer
only relative protection: “At
best, these vaccines induce an immune
response that lessens the severity
of disease; vaccinates are not immune
to infection, nor are they protected
from all signs of disease.”
Adds Dr. Schultz, “Quite honestly,
with regard to herpes, the efficacy
of the products is not great. Unlike
parvo and adeno, where you have 99%
of the animals capable of responding
and developing an effective immune
response, you’re lucky if you
have 70% with herpes. There is also
the potential of enhancing the likelihood
of a carrier state.” In spite
of this, FHV-1 is still considered
a core vaccine; even though it doesn’t
provide complete protection, it at
least helps ensure the cat won’t
become seriously ill if he does catch
the virus, an important consideration
for a disease that’s as widespread
and infectious as herpes. Again, though,
as with the other cores, annual vaccination
is unnecessary. According to AAFP,
the vaccine for FHV-1 offers protection
for at least three years, while other
research indicates the duration of
immunity is much longer.
In the third and final article in
this series, due to appear in our
next issue, we’ll take a close-up
look at the remaining two core vaccines,
canine adenovirus-2 and feline calicivirus.
ONE
WOMAN’S FIGHT TO CHANGE VACCINATION
LAWS
In the fall of 2003, Kris Christine
of Alna, Maine, took her Labrador
retriever, Meadow, to the vet for
his biannual rabies vaccination, as
required by state law. A few months
later, the dog developed a cancerous
mast cell tumor at the site of the
vaccination, and had to undergo two
operations that involved having a
portion of his hind leg removed.
Devastated by what had happened to
Meadow, Kris did some research into
the over-vaccination issue. What she
discovered turned her into a resolute
crusader, and she’s been busy
ever since educating people about
the dangers of over-vaccination and
questioning the frequency with which
vaccines are administered.
Kris’s determination has paid
off. Last year, she successfully lobbied
to have Maine change its rabies vaccination
requirements from two to three years.
Now, she’s pushing the Legislature
to pass a new law requiring state
veterinarians to provide disclosure
forms citing the pros and cons of
vaccination.
“If this legislation passes,
it is only a matter of time before
other states follow suit,” says
Kris. “Already, pet owners in
Connecticut, Pennsylvania, Florida,
Nevada, Montana, and Texas have contacted
me saying they are going to ask their
legislators to file similar bills.”
Learn more at www.mainelegislature.org/legis/bills/billtexts/LD042901-1.asp.
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