|
New
Principles in Canine Immunology
Immunity is not controlled entirely by antibody levels as we
once thought. Immunity is controlled by memos/dogphotsm.jpgry
cells. Memory cells are B and T lymphocytes. These are white
blood cells which stand ready in the body to respond with
protective antibodies when challenged by a disease agent.
Memory cells, once programmed, persist
for the lifetime of the animal. Therefore it is
possible to have low antibody levels (or titer) and still
have protective immunity. Although memory cells cannot be
measured, their presence can be demonstrated by challenge
studies.
Dogs' & cats' immune systems mature
fully at 6 months. If a modified live virus (MLV)
vaccine is given after 6 months of age, it produces an
immunity which is good for the life of the pet (i.e. canine
distemper, parvo, feline distemper) Modified live virus
vaccines must replicate to stimulate the immune system. If
another MLV vaccine is given, the antibodies from the first
vaccine block the replication of the new virus. The actively
acquired immunity in effect neutralizes the antigens of
second vaccine, and there is little or no effect. The
titer (level of immunity) is not "boosted" nor are memory
cells expanded.
Not only are annual boosters for parvo
and distemper unnecessary (6), they subject the pet
to the potential risk of adverse
reactions like allergic reactions, Immune Mediated
Hemolytic Anemia (a disease where the dog rejects its'
own blood) and Injection Site Fibrosarcomas for cats.
The AVMA Council on Biologic and Therapeutic Agents has
stated: There is no scientific
documentation to back up label claims for annual
administration of modified live virus vaccines.
Puppies receive antibodies through their mother's milk (colostrum)
the very first time they nurse. This natural protection can
last up to 8 - 14 weeks. Puppies & kittens should not be
vaccinated at less than 8 weeks. Maternal immunity will
neutralize the vaccine & only a few (0 -35%) will be
protected. Unfortunately, taking this unprotected baby out
of the house and to a veterinary clinic will expose it to
parvovirus without protection. Vaccination at home by a
breeder at 6 weeks may provide protection for some
puppies (0 -35%) It is not the vaccination at 6 weeks that
is objectionable, but the increased risk of exposure to the
Parvovirus you are trying to protect against.
Vaccination at 6 weeks will, however,
delay the timing of the first highly effective vaccine.
Vaccination of dogs for Distemper at too young of an age has
been shown to cause Hypertropic Osteodystrophy, especially
in Weimaraners. Vaccinations given 2 weeks apart suppress
rather than stimulate the immune system .
A series of vaccinations is recommended starting at 8 weeks
and given 3 - 4 weeks apart up to 16 weeks of age. Another
MLV vaccination given sometime after 6 months of age
(usually at 1 year & 4 months) will provide lifetime
immunity .
Current Recommendations for Dogs
Distemper and Parvovirus
In 1994, Ft. Dodge marketed a new high titer Parvovirus
vaccine (RF11). Testing by Dr. Ron Schultz demonstrated
that this vaccine and a new high titer vaccine from
Immunovet (Proguard) provided much better protection than
all other vaccines against canine parvovirus . When
studies by Dr Schultz demonstrated that
the new high titer vaccines by Fort
Dodge and Intervet were much more effective, Meriel
improved their product to match. Pfizer came out
with a high titer vaccine, Vanguard puppy.
Pfizer and Biocor still market the
old vaccines, Vanguard 5 and Biocor.
The frustrating experiences we had prior to 1995, with
vaccine breaks were largely resolved by the new improved
vaccines. Attempts to improve the efficacy by more
frequent administration of the vaccine are no longer
necessary.
According to Dr. Schultz in the Journal of the AVMA Aug.
15. 1995, when a vaccination series given at 2, 3, and 4
months and again at 1 year(>6m0) with a modified live
virus, puppies and kittens program memory cells that
survive for life, providing lifelong immunity for
diseases like Parvo and Distemper.
Dr. Leland Carmichael at Cornell University and Dr.
Schultz have studies showing immunity against challenge at
7 years for canine distemper and 7 years for parvovirus;
and immunity by serology out to 15 years for distemper. .
Studies for longer duration are pending. *A copy of
Dr Schultz's study is in our pet care library for your
convenience.
Adverse events from canine distemper
vaccine include vaccine induced distemper, vaccine induced
folliculitis, and HOD (hypertropic osteodystrophy). HOD is
most common in Wiemaraners.
Virus drift There are no new strains
of parvovirus as some would like to suggest. Parvovirus
vaccination provides cross immunity for all types.
Dogs will not get Parvo from the vaccine,
but when the vaccine is administered at a vet
clinic to 6 wk old puppies only 30% will respond to the
vaccine with any protection while all will likely be
exposed. It is likely some of them will come down
with parvo which they caught at the Vet Clinic.
For this reason we do not start the initial series of
vaccinations until the puppies are 8 wks old and are better
able to respond to the vaccine.*** It is not the
vaccination at 6 wks that I object to but the increased
exposure to the virus at the Vet Clinic at an age when
maternal antibodies will interfere with the response to the
vaccination. I would encourage breeders who have a
problem with Parvovirus to vaccinate puppies at home with
Parvo, but not Distemper, and only at 6 weeks and no
younger, to aid in cutting losses.
Hepatitis (Adenovirus)
(CAV2) is one of the agents known to be a cause of
"kennel cough." Only vaccines with CAV-2 should be used as
CAV-1 vaccines carry the risk of "hepatitis blue-eye"
reactions and kidney damage. Hepatitis (CAV1) in dogs is a
very rare disease. I see several cases per year of "blue
eye" from CAV 1 Vaccine purchased at a feed store. I have
never seen a dog with hepatitis.
Bordetella - Parainfluenza
Commonly called "kennel cough," the Parainfluenza
vaccine is recommended only for those dogs boarded,
groomed, taken to dog shows, or for any reason housed
where exposed to a lot of dogs. The intranasal vaccine
provides more rapid onset of immunity with less chance of
reaction . Immunity requires 72 hours and does not protect
from every cause of "kennel cough"
The vaccine does not contain the serovar of bordetella
that a dog would likely be exposed to. It is the
parainfluenza portion that is of benefit. Unfortunately an
intranasal vaccine for parainfluenza without bordetella is
not available.
Rabies
Although there have been no reported cases of rabid
dogs or cats in Harris County, Montgomery County, or Ft.
Bend County, there have been rabid skunks and bats, so the
potential exists.
If a dog or cat bites someone and is not vaccinated, it
must be quarantined in a licensed facility. Rabies
vaccine is highly recommended for your pets protection.
This is a killed vaccine. Killed vaccines provide a
shorter duration of immunity than MLV . Duration of
immunity for rabies vaccine has been shown to be at least
7 years.
In Texas, rabies vaccination is required to be
administered at four months of age, one year later, and
then every three years for dogs. To help prevent injection
site fibrosarcomas, a one year duration of immunity non-
adjuvanted vaccine, Purevac, has been approved for cats.
This vaccine must be administered annually. A three year
license is pending.
Canine corona virus
This is only a disease of puppies
less than eight weeks of age . It is a rare,
self-limiting disease (i.e. dogs get well in 3 days
without treatment). Corona virus does not cause disease in
adult dogs. Cornell University and Texas A&M
University have only diagnosed one case each in the last 7
years. For a veterinarian to make a diagnosis of Corona
Virus based on clinical signs is highly presumptive. Only
electron microscopy of feces can verify the presence of
canine corona virus. This is only done at places such as
Texas A & M Diagnostic Laboratory, and they report no
positive tests. The presence of the virus does not
indicate it is the cause of disease. Dogs over 8 wks of
age cannot and have not been experimentally induced to
exhibit disease from corona virus. This is age related
immunity.
Immunologists have reason to believe that the vaccine does
not work. Mucosal secretory IgA antibodies would be
necessary to protect a dog against this disease & an
injectable vaccine will not provide this type of
protection. I see no justification for the use of corona
virus vaccine.
In 1985 a significant number of dogs
died from encephalitis caused by Corona Virus vaccine,
combined with the Rockborn strain distemper. An
unfortunate & heartbreaking catastrophe caused by an
unnecessary vaccine.
Leptospirosis
This vaccine is a common cause of adverse reactions in
dogs ranging from life threatening anaphylactic reactions
to mild facial swelling and urticaria.
Leptospirosis is an infection of the kidneys and liver.
Dogs and people get it from contact with urine from rats,
raccoons, cows and pigs. The risk of contagion from dogs
to humans is very low.
Most of the clinical cases of leptospirosis reported in
dogs in the U.S. are caused by serovars (or types) L.
grippotyphosa, L. pomona and L. bratislava. The most
commonly used vaccines contain different serovars-L.
canicola & L.icterohaemmorrhagiae. Cross protection is not
provided and protection is short-lived (6 - 7 months) New
Vaccines recently introduced by Fort Dodge include L.
grippotyphosa., and L. pomona .
Although Leptospirosis in dogs seems to be increasing in
Michigan, Wisconsin, Ohio, and New York, this disease is
rare in Texas. Records at Texas Veterinary Medical
Diagnostic Lab show an average of 12 cases of
Leptospirosis in dogs in Texas per year. In 2000 the
TVMDL recorded L. Icterohaemorrhagiae -3 cases, L.
canicola -2, L. pomona -2, L grippotyphosa -1. Texas A&M
University reports 31 cases in 21 years. Although this is
a serious and life threatening disease, in a state with an
estimated dog population of over 7 million, I do not think
the risk justifies routine vaccination, with two vaccines
twice per year.
This vaccine should not be given to
puppies less than 16 weeks of age as it is very
immunosuppressive. It can interfere with immunization
against parvo & distemper. Reactions are common. Deaths
due to immunosupression can occur.
Lyme Disease
Lyme disease is a tick born disease which can cause
lameness, kidney failure and heart disease in dogs and
people. Ticks transmit the disease to humans. Eighty five
percent of Lyme disease cases in dogs in the USA are found
in nine New England area states Michigan and Wisconsin.
We do not have Lyme disease in Texas. In the N.E. U.
S. Ixodid ticks acquire the Lyme disease organism from
the deer mouse. The Ixodid tick in Texas feeds on lizards
which do not transmit Lyme disease.
Confusion as to the occurrence of Lyme disease in Texas
exists due to three things. #1. In Texas we have a disease
that closely resembles Lyme Disease, Southern Tick
Associated Rash Illness or STARI cause by Borrelia
lonestari and spread by the Lone Star Tick. ( Lyme disease
is caused by Borrelia burgdoferi and spread by Ixodes
scapularis.) #2.Lyme disease testing with the most
commonly used test can give a false positive reaction to
normal spirochete organisms in a dogs mouth. #3
Manufacturers of the vaccine and the test exaggerate the
incidence of the disease in order to sell their product.
Texas A&M University has never seen a case of Lyme disease
in a dog from Texas.
The advent of a new ,more accurate Lyme disease Test (Snap
Test by Idexx) in 2000 will hopefully give us better
information about the non-existence of this disease in
Texas.
The average dog in Houston would be at no risk of
contracting Lyme disease. If you travel to endemic areas
with your dog, you may still want to consider the safety &
effectiveness of Lyme disease vaccine. Dr. Jacobson,
Cornell Diagnostic Lab, reported a temporal relationship
of 327 dogs which developed polyarthritis after
vaccination with Lyme disease vaccine. These dogs did not
show antibody titers suggestive of Lyme disease
infection. Other causes of arthritis were ruled out. Lyme
vaccine has been demonstrated to cause arthritis in
hamsters. There is a class action suit in human medicine
for failure to warn people about the possibility of
developing polyarthritis from human Lyme disease vaccine.
The main antigen displayed by the Lyme disease organism
inside the dogs body is Outer Surface Protein B- OSP B.
Newer PCR vaccines by Muriel and Schering only contain
OSP A antigens. The importance of OSP B & C antigens were
discovered after the new vaccines were developed .
Theoretically OSP A antibodies in the blood of an
immunized dog are ingested by a tick. This prevents the
bacteria from reproducing within the tick and therefore
from being injected into the dog, if antibodies are in
high enough concentrations.
Most Colleges of Veterinary Medicine do not recommend
Lyme Disease vaccine.
Lyme disease prevention should
emphasize early removal of ticks. Ticks must be attached
to the dog for 24 hours to transmit the disease.
Amitraz (Preventick) collars are more effective than
Frontline as Amitraz paralyzes the tick’s mouth parts
preventing transmission of disease .
Amitraz tick collars should be used with extreme caution,
as they are toxic if chewed on or swallowed by a dog or
children. Frontline takes 24 - 48 hours to kill
ticks, allowing for the possibility of disease
transmission. This is an important aid in tick control,
but will not prevent the transmission of tick born
diseases like Lyme disease, Ehrlichia, Babesia or Rocky
Mountain Spotted Fever. Vaccinating
pets against Lyme disease does not provide any protection
for the owners.
VACCINATION NEWSFLASH
All 27 veterinary
schools in North America are in the process of changing
their protocols for vaccinating dogs and cats. Some of
this information will present an ethical & economic
challenge to vets, and there will be skeptics. Some
organizations have come up with a political compromise
suggesting vaccinations every 3 years to appease those who
fear loss of income vs. those concerned about potential
side effects. Politics, traditions, or the doctor's
economic well being should not be a factor in medical
decision.
NEW PRINCIPLES OF
IMMUNOLOGY
"Dogs and cats immune systems mature fully at 6 months. If
a modified live virus vaccine is given after 6 months of
age, it produces an immunity which is good for the life of
the pet (ie: canine distemper, parvo, feline distemper).
If another MLV vaccine is given a year later, the
antibodies from the first vaccine neutralize the antigens
of the second vaccine and there is little or no effect.
The titer is not "boosted" nor are more memory cells
induced." Not only are annual boosters for parvo and
distemper unnecessary, they subject the pet to potential
risks of allergic reactions and immune-mediated hemolytic
anemia. "There is no scientific documentation to back up
label claims for annual administration of MLV vaccines."
Puppies receive antibodies through their mothers milk.
This natural protection can last 8-14 weeks. Puppies &
kittens should NOT be vaccinated at LESS than 8 weeks.
Maternal immunity will neutralize the vaccine and little
protection (0-38%) will be produced. Vaccination at 6
weeks will, however, delay the timing of the first highly
effective vaccine. Vaccinations given 2 weeks apart
suppress rather than stimulate the immune system. A series
of vaccinations is given starting at 8 weeks and given 3-4
weeks apart up to 16 weeks of age. Another vaccination
given sometime after 6 months of age (usually at 1 year 4
mo) will provide lifetime immunity.
CURRENT RECOMMENDATIONS
FOR DOGS
Distemper & Parvo "According to Dr. Schultz, AVMA,
8-15-95, when a vaccinations series given at 2, 3 & 4
months and again at 1 year with a MLV, puppies and kitten
program memory cells that survive for life, providing
lifelong immunity." Dr. Carmichael at Cornell and Dr.
Schultz have studies showing immunity against challenge at
2-10 years for canine distemper & 4 years for parvovirus.
Studies for longer duration are pending. "There are no new
strains of parvovirus as one mfg. would like to suggest.
Parvovirus vaccination provides cross immunity for all
types." Hepatitis (Adenovirus) is one of the agents known
to be a cause of kennel cough. Only vaccines with CAV-2
should be used as CAV-1 vaccines carry the risk of
"hepatitis blue-eye" reactions & kidney damage. Bordetella
Parainfluenza: Commonly called "Kennel cough" Recommended
only for those dogs boarded, groomed, taken to dog shows,
or for any reason housed where exposed to a lot of dogs.
The intranasal vaccine provides more complete and more
rapid onset of immunity with less chance of reaction.
Immunity requires 72 hours and does not protect from every
cause of kennel cough. Immunity is of short duration (4 to
6 months).
RABIES
There have been no reported cases of rabid dogs or cats in
Harris, Montogomery or Ft. Bend Counties [Texas], there
have been rabid skunks and bats so the potential exists.
It is a killed vaccine and must be given every year. Lyme
disease is a tick born disease which can cause lameness,
kidney failure and heart disease in dogs. Ticks can also
transmit the disease to humans. The original Ft. Dodge
killed bacteria has proven to be the most effective
vaccine. Lyme disease prevention should emphasize early
removal of ticks. Amitraz collars are more effective than
Top Spot, as amitraz paralyzes the tick's mouth parts
preventing transmission of disease .
NEW RECOMMENDATIONS FOR CATS
Feline vaccine related Fibrosarcoma is a type of terminal
cancer related in inflammation caused by rabies & leukemia
vaccines . This cancer is thought to affect 1 in 10,000
cats vaccinated. Vaccines with aluminum adjuvant, an
ingredient included to stimulate the immune system, have
been implicated as a higher risk.We now recommend a non-adjuvanted
rabies vaccine for cats . Testing by Dr. Macy, Colorado
State, has shown this vaccine to have the lowest tissue
reaction and although there is no guarantee that a vaccine
induced sarcoma will not develop, the risk will be much
lower than with other vaccines. Program injectable 6 mo
flea prevention for cats has been shown to be very tissue
reactive & therefore has the potential of inducing an
injection site fiborsarcoma. If your cats develops a lump
at the site of a vaccination, we recommend that it be
removed ASAP, within 3-12 weeks.
FELINE LEUKENIA VIRUS
VACCINE
This virus is the leading viral killer of cats. The
individuals most at risk of infection are young outdoor
cats, indoor/outdoor cats and cats exposed to such
individuals. Indoor only cats with no exposure to
potentially infected cats are unlikely to become infected.
All cats should be tested prior to vaccination. Cats over
one year of age are naturally immune to Fel.V whether they
are vaccinated or not, so annual vaccination of adult cats
is NOT necessary. The incubation period of Feline leukemia
can be over 3 years, so if your cat is in the incubation
state of the disease prior to vaccination, the vaccine
will not prevent the disease.
FELINE PANLEUKOPENIA VIRUS
VACCINE
Also called feline distemper is a highly contagious and
deadly viral disease of kittens. It's extremely hardy and
is resistant to extremes in temperature and to most
available disinfectants. Although an effective treatment
protocol is available, it is expensive to treat because of
the serious nature of the disease and the continued
presence of virus in the environment, vaccination is
highly recommended for all kittens . Cats vaccinated at 6
month or older with either killed or MLV vaccine will
produce an immunity good for life. Adult cats do NOT need
this vaccine.
Feline Calicivirus/Herpesvirus Vaccine.
Responsible for 80-90% of infectious feline upper
respiratory tract diseases. The currently available
injectable vaccines will minimize the severity of upper
respiratory infections, although none will prevent disease
in all situations .. Intranasal vaccines are more
effective at preventing the disease entirely. Don't worry
about normal sneezing for a couple of days. Because
intranasal vaccines produce an immunity of shorter
durations, annual vaccination is recommended.
VACCINES NOT RECOMMENDED
Chlamydia or pneumonitis. The vaccine produces on a short
(2 month) duration of immunity and accounts for less than
5% of upper respiratory infections in cats.The risks
outweigh the benefits.
Feline Infectious Peritonitis.
A controversial vaccine. Most kittens that contract FIP
become infected during the first 3 months of life. The
vaccine is labeled for use at 16 weeks. All 27 vet schools
do not recommend the vaccine.
Bordetella
A new vaccine for feline bordetella has been introduced.
Dr. Wolfe of Texas A&M says that bordetella is a normal
flora and does not cause disease in adult cats. Dr. Lappin
of Colorado State says that a review of the Colorado State
medical records reveals not one case diagnosed in 10
years.
NEW DEVELOPMENTS
Giardia is the most common intestinal parasite of humans
in North America, 30% or more of all dogs & cats are
infected with giardia. It has now been demonstrated that
humans can transmit giardia to dogs & cats & vice versa.
Heartworm preventative must be given year round in Houston
.
VACCINES BADLY NEEDED
New vaccines in development include: Feline
Immunodeficiency Virus and cat scratch fever vaccine for
cats and Ehrlichia [one of the other tick diseases, much
worse than Lymes] for dogs.
THE VIEW FROM THE TRENCHES; BUSINESS ASPECTS
Most vets recommend annual boosters and most kennel
operators require them. For years the pricing structure of
vets has misled clients into thinking that the inherent
value of an annual office visit was in the "shots" they
failed to emphasize the importance of a physical exam for
early detection of treatable diseases. It is my hope that
you will continue to require rabies & Kennel cough and
emphasize the importance of a recent vet exam. I also hope
you will accept the new protocols and honor these pets as
currently vaccinated. Those in the boarding business who
will honor the new vaccine protocols can gain new
customers who were turned away from vet owned boarding
facilities reluctant to change.
CONCLUSION
Dogs & cats no longer need to be vaccinated against
distemper, parvo, & feline leukemia every year . Once the
initial series of puppy or kitten vaccinations and first
annual vaccinations are completed, immunity from MLV
vaccines persists for life. It has been shown that cats
over 1 year of age are immune to Feline Leukemia whether
they have been vaccinated or not. Imagine the money you
will save, not to mention less risks from side effects.
PCR rabies vaccine, because it is not adjuvanted, will
mean less risk of mediated hemolytic anemia and allergic
reactions are reduced by less frequent use of vaccines as
well as by avoiding unnecessary vaccines such as K-9
Corona virus and chlamydia for cats, as well as
ineffective vaccines such as Leptospirosis and FIP.
Intranasal vaccine for Rhiotracheitis and Calici virus,
two upper respiratory viruses of cats provide more
complete protection than injectable vaccines with less
risk of serious reactions. The AAHA and all 27 veterinary
schools of North America are our biggest endorsement for
these new protocols.
|
