| Equine Diseases
Equine Strangles:
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Just the word “Strangles” can strike fear into the
hearts of horse owners. Despite the fact that it is
fatal only about 3% of the time, it remains a dreaded
disease. Its highly contagious nature and obvious and
severe symptoms are difficult to ignore.
Strangles is spread by a bacterium called
Streptococcus equi. The bacteria gains access to the
horse through the mouth or nasal area, where it grows on
the horse's tonsillar tissue. It then spreads to the
lymph nodes in the back of the throat, leading to an
infection accompanied by a fever, loss of appetite, and
general malaise. Generally, disease occurs within 3-14
days of exposure to the bacteria. Over time, the lymph
nodes will fill with pus, and then rupture and drain. As
the lymph nodes swell, they become large and painful.
The horse will often stand with his neck stretched out
in an attempt to relieve the pressure. The horse may
also cough or develop loud and difficult breathing due
to the pressure on his throat. The sounds the horse
makes while breathing are what gave rise to the name
“Strangles”. In up to 10% of cases, the bacteria may
invade lymph nodes in the chest and abdomen, resulting
in serious and life-threatening disease. This is termed
disseminated or “bastard” strangles and is much more
dangerous than the disease’s normal course.
 Strangles
is almost always contracted from another horse. The
disease is very contagious, and the bacteria may survive
in the nasal passages, throat, and guttural pouches of
the horse for weeks to months following recovery. These
horses often spread the disease as people think they are
“cured” and allow them to intermingle with other horses
again. Touching noses, sharing water sources, and
sharing feed sources are all avenues by which the
Strangles bacteria travels from one horse to the next In
addition, it can be spread by buckets, feeding
equipment, bits, and people who handle the horses . The
Strangles bacterium is generally only a health danger to
the horse and does not cause disease in humans. Usually
young horses are most severely affected as they lack
immunity to the disease. The disease is most likely to
be fatal in foals, especially those who did not receive
good colostral immunity from their dams.
 The
Strangles bacteria can live for significant lengths of
time on exposed surfaces. It can survive 3 days to one
week on stall surfaces, soil and other places. In
freezing weather it can persist indefinitely, though.
Water can be a significant source of infection as the
bacteria can survive in water for up to six weeks. Most
stables can be safely repopulated after a Strangles
outbreak, but care should always be taken to clean and
disinfect the water sources prior to introducing horses
again.
So what if your horse DOES develop this disease?
Well, first of all, care is directed at keeping the
horse comfortable. This may include non-steroidal
anti-inflammatory drugs such as Ban amine for pain and
fever reduction, liniment or hot-packing of abscesses,
and sometimes antibiotic use. Antibiotic use is often
avoided in Strangles cases, because it is difficult to
penetrate the abscess with antibiotics, and antibiotics
can actually make it take more time for the horse to
recover. In addition, while horses who recover from
Strangles without antibiotics will have long-standing
immunity to the disease, horses treated with antibiotics
may not. When antibiotics are used, Penicillin given
early in the course of the disease is the best option.
If the abscesses are so large they interfere with
breathing or swallowing, they may be lanced and drained
by your veterinarian. In these cases, flushing of the
abscesses with an iodine solution may also be needed if
possible.
 In
many ways, the most difficult part of dealing with
Strangles infections is to prevent the spread of the
disease to other horses. Meticulous care should be used
to prevent spread of the disease to other horses. The
affected horse or horses should be isolated. The area
where they are housed should be considered contaminated
until 1 month following the horse’s recovery. Isolation
and care to prevent any contact of the affected horse or
any equipment used with him from coming into contact
with other horses on the farm is the only way to prevent
the spread. Once Strangles has been diagnosed on the
farm, no horses should come in or out until the premises
are clean. This means minimally until there are no new
cases for three weeks. However , three negative nasal
swabs on all affected horses is the “gold standard” for
calling a barn “clean” from Strangles.
To prevent Strangles outbreaks, horses newly arriving
to a barn should be isolated for a period of 2 to 3
weeks. Horses that have shown no symptoms after 3 weeks
are at low risk of spreading disease, although there are
occasional horses that have no signs but may still
spread the disease. If you are traveling with your horse
bring your own buckets, feed containers etc if possible.
If it is not possible, then disinfect feed and water
containers prior to use. Also, ascertain that the stalls
being used are disinfected in between horses. Minimizing
stress on your horse will also help protect him from
disease.
 Vaccines
exist but are not without their issues. The
intra-muscular strangles vaccine is associated with
painful inflammation at the injection site, and vaccine
reactions. The intranasal vaccine is safer but must be
properly administered or else it is ineffective. In
addition, because it is a live vaccine, it is possible
to cause abscesses if appropriate care is not taken when
the Strangles vaccine is administered along with other
vaccines. Both vaccines require boosters ever 6 months
for optimal immunity. Vaccinating once an outbreak has
begun is not recommended as this increases the risk of a
fatal complication called purpura hemorrhagica.
The good news is that most horses will make an
uneventful recovery from Strangles, and acquire a
lasting immunity to the disease. If you think your horse
may have Strangles you should always contact your
veterinarian right away.
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Denise Bickel DVM
Whole Horse Veterinary Services
Phone # 517-474-4050
Fax # 517-764-7710
3906 Seymour Rd
Jackson, MI 49201
EMAIL US
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