Tracy Walker, DVM
The Healthy Horse
Route 1 Box 115
Elkins, WV 26241
(304) 636-8363
Late Spring 2006
Vaccines Part 2
In the last newsletter we discussed the basic types of vaccine. Remember that all vaccines are not created equal and not all vaccines are
appropriate for every horse. This month we will discuss vaccines available for specific diseases.
Core Vaccines for Horses in West Virginia - These vaccines should be given to all horses regardless of environment or use. Keep
in mind that this is list is specifically for horses in this area of West Virginia. Remember, mares should receive their annual vaccinations in
the last 30 days of pregnancy. This maximizes the safety of the foal and the mare.
Tetanus
Toxoid
Eastern &
Western
Encephalitis
Influenza
Rabies
West Nile
Virus
Symptoms
The bacteria that causes tetanus is found all over barnyards in mud
and fecal matter. Horses are very sensitive to the toxin released
by this bacteria. Most horses become infected via an open wound,
although an incriminating wound is not always found. An
affected horse will become paralyzed in a stiff position. In the
early stages, this disease can be treated but most often it results in
death.
This disease is caused by a virus that is carried by mosquitos.
Humans can also be infected by mosquitos. This disease will
cause neurologic symptoms such as dementia, difficulty walking,
and seizures. This disease can be treated but most often results in
death. Horses that survive this disease often have permanent
neurologic problems.
This disease can cause moderate to severe respiratory disease
which could predispose your horse to developing pneumonia.
Interval
* Annual Booster
* Boosters are often
given when a wound
occurs.
Safety & Effectiveness
This vaccine is very
effective. Reactions may
occur but are very rare.
* Annual Booster
This booster is most
effective when given in
the Spring to maximize
immunity during the
mosquito season.
Annual Booster with
the killed vaccine.
This vaccine is very
effective. Reactions may
occur but are very rare.
An intranasal vaccine for flu is available. It is very effective but
immunity does not last as long as the intramuscular vaccine. This
intranasal vaccine is recommended for horses that are frequently
stressed, traveling, shown and campaigned. This vaccine should
be boostered every 3 months. The intranasal vaccine should not
be used in pregnant mares.
Every 3 months with
the intranasal vaccine.
This disease is caused by a virus that is carried by bats, raccoons,
oppossums and fox (just to name a few). The disease is
transferred most often by a bite or contact with saliva of an
infected animal. In horses, this disease will cause neurologic
symptoms such as depression, & coma. Aggressive behaviour
may or may not occur. All animals infected with rabies will die
from neurologic symptoms or are humanely euthanized due to the
danger of human infection.
This disease is caused by a virus that is carried by mosquitos.
Early signs may include mild hindlimb lameness and facial
twitching. Affected horses may have mild signs or progress to
seizures and death.
Annual Booster
Annual Booster
This booster is most
effective when given in
the Spring to maximize
immunity during the
mosquito season.
This vaccine is very
effective. I usually give
the killed vaccine as a
combination with the “4way”.
The intranasal vaccine is
superior in effectiveness
to the intramuscular
vaccine, but requires
frequent boosters.
This vaccine is very
effective. Reactions may
occur but are very rare.
This vaccine is very
effective.
Horse Owner’s Workshop
Saturday, May 6, 2005
9:00 AM at Camp Pioneer Barn/Riding Arena
A morning of presentations on nutrition and horse health. Topics will include supplements and preventative care.
I strongly encourage horse owners of all ages and experience to attend. Please RSVP to me at trwalker3@aol.com
Non-Core Vaccines – These vaccines should be recommended on an individual case basis. Whether your horse should receive these
vaccines, depends upon environment and use. For example, pregnant mares and show horses will frequently receive additional vaccinations.
Symptoms
Interval
Effectiveness
Rhinopneumonitis This disease is caused by a herpesvirus. EHV-1 is associated
Pregnant mares should
This vaccine is the most
with abortion, neurologic disease, and respiratory disease. EHV- be boostered at 5,7, 9 & common culprit for
4 is generally restricted to respiratory infections. Horses are
11 months of gestation reactions that I have
often infected with this at a young age and transiently shed it
with a killed EHV-1
experienced. Some
throughout life during periods of stress. This disease is
vaccine.
horses will get severe
transmitted by aerosol and contact with tissue and placentas of
localized swelling and
aborted foals.
Show horses and other
muscle soreness at the
horses that are in high
vaccine site. It is
There have been recent outbreaks of this neurologic form of this
risk populations should important to note that the
disease in race horses in Maryland and Kentucky. It is
be vaccinated every 4- current EHV vaccines do
interesting that these populations are among the most diligently
6 months with a killed
not block infection, but
vaccinated for this disease. This is prompting more research on
EHV 1/4 or a modified
rather decrease shedding
the details of herpesvirus and how is lives in the body. There
live EHV1.
and potential infection of
should be new vaccines and information surfacing in the next
herdmates. None of the
year.
vaccines that are
currently available are
labeled to protect against
the neurological disease.
Potomac Horse
This disease, occurring mostly from May to October, is caused
Annual Booster
This vaccine has
Fever
by a rickettsia that is found in certain streams and rivers. The
This booster is most
questionable
life cycle of the infectious agent includes freshwater snails, a
effective when given in effectiveness. It is not
parasite within the snail, and flies along the riverbeds (including
the Spring to maximize uncommon for vaccinated
mayflies, dragonflies, caddisflies, and damselflies). Horses are
immunity during the
horses to develop disease.
most likely infected from ingesting the adult flies or infected
Summer season.
However, there are no
larvae in water sources or contaminated grazing areas next to
specific adverse effects
streams. Affected horses are severely depressed and develop
Additional Booster
from giving this vaccine.
endotoxemia and profuse diarrhea. Many horses will die
This is recommended
regardless of treatment. However, some horses will survive with in July on farms that
early diagnosis and aggressive treatment.
have had confirmed
cases of Potomac Horse
Fever.
Strangles
This disease causes severe upper respiratory disease especially in Vaccination is
The intranasal vaccine is
young horses. Affected horses will have mild to profuse creamy generally only
very effective but not
nasal drainage and enlarged abscesses under the jaw and
recommended in an
without side effects. The
throatlatch. Abscesses may spontaneously rupture and drain. It
outbreak or if your
intranasal vaccine is a
is extremely contagious to other horses. Many horses will be
horse is traveling to an
modified live virus and
infected and recover without major complications. However,
area with a know
should not be used in
some horses will develop life threatening complications
problem. Boosters
pregnant mares. A severe
including internal abscesses.
should be given every
potentially deadly
six months.
vascular complication of
Vaccines are available as a modified live intranasal vaccine and
purpura hemorhagica can
a killed intramuscular vaccine.
The IM vaccine can be
occur. Severe localized
given to mares 30 days
swelling and pain has
prior to foaling.
been associated with the
IM vaccine.
Venezualan
This is similar to the WEE & EEE included in the core vaccines. * Annual Booster
This vaccine is very
Encephalitis
This occurs in Central and South America. An outbreak
This booster is most
effective. Reactions may
occurrec most recently in Southern Mexico in 1993. However,
effective when given in occur but are very rare.
Venezualan encephalitis has not been diagnosed in the US for
the Spring to maximize
over 20 years. This vaccine is only recommended for horses
immunity during the
along states bordering Mexico. I do not routinely vaccinate for
mosquito season.
this disease. It is only recommended for those horses traveling
to Texas and the Southwest for showing and training.
There are many other vaccines available on the market for diseases such as botulism, rotavirus, anthrax and equine viral arteritis. Most of
these are used on broodmare farms. In addition, vaccines are often sold in a combination as a “4-way”. Remember, that not all “4-way”
vaccines protect against the same diseases. The standard 4-way vaccine that I use includes WEE, EEE, tetanus and flu. And, just because a
vaccine is sold as a “5-way” or “7-way” etc. does not mean that it is the best vaccine for your horse. Vaccines and recommendations are
constantly changing as new diseases emerge and we learn more about existing diseases. I am constantly updating my recommendations as
new information becomes available. I am happy to customize a vaccine protocol for your horse’s specific needs.
Internet Rumors & Recalls……..Sorting out the truth.
The internet is a easily accessible resource for an unlimited amount of information. However, you must carefully consider the source,
author and sponsor of any given website. I wanted to clarify a few of the recent rumors that several of you have asked me about.
1. Bimectin, a generic Ivermectin paste from Country Supply, killed a barn full of horses out West.  False.
This did not happen and represents the epitome of internet rumor. The story varies from a ranch to an Andalusian barn. The
original email surfaced in October 2005. The lot number in question (5J019) was tested by the company and no contaminants,
impurities or
inconsistencies with the labeled dose and concentration were found. This product is an FDA approved
product, which means that it has been tested and approved for safety and effectiveness. True reactions to the product would be
immediately reported to the FDA
and information disseminated appropriately. For more information you can read the press
releases from the manufacturer at
www.bimeda.com. Still doubting…..ask Sonya Penson. She just dewormed 13 horses
with Bimectin with no ill effects.
2. West Nile Vaccine caused abortions in mares. 
False
This rumor originated from a poorly researched article published in the Denver newspaper. The article claimed that an owner
vaccinated his horses with West Nile Vaccine and they all aborted. This was a big discussion at the national equine vet
conference this past December. No official reports of vaccine reactions were ever filed with the company or the FDA and all
claims from the
Denver article remain unsubstantiated. This vaccine is not yet labeled for use in pregnant mares but studies
have shown no
detrimental effects when used on pregnant mares. Regardless, no pregnant mare should ever be
vaccinated in the first 60 days
of pregnancy. Just as in people, this is a very fragile period for the fetus. During the first
60 days of pregnancy, even stress such as
a fever or simple cold can cause abortion.
3. Diamond Pet Food is contaminated and will cause liver failure and death in dogs.  True
Sadly, this is true. I was first notified of this recall in early December. Several batches of dog food from this manufacturer
were
contaminated with aflatoxin. This toxin causes irreversible liver damage in dogs which eventually progresses to
death. Food from contaminated batches was known to be delivered to many states on the East coast, including West Virginia.
The manufacturer has
been very aggressive in its attempt to notify the public of this hazard. Information has been
circulated through television, national news, local news, veterinary organizations and retailers. For more information on this
recall and the exact brand names of food involved, go to the recall website at www.diamondpetrecall.net. If you believe that
your dog has eaten this food, blood tests
can confirm whether or not there has been damage to the liver.
Rest assured that in the event of a legitimate product recall, I will post information on the website (www.alleghenyequine.com) and
in this newsletter.
Tracy Walker, DVM
Route 1 Box 115
Elkins, WV 26241