Strangles
life
EQUESTRIAN - Sponsored by Brickfields and Froghill Tack
Written by: Amanda Watson
The British Horse Society
Strangles is one of the most
commonly diagnosed infectious
diseases afflicting all species of
equines worldwide. Caused by
the bacterium Streptococcus equi
(S.equi), this disease is highly
contagious and can affect any age
or breed of horse and remains one
of the most feared diseases as it
can be potentially fatal.
Strangles not only causes great pain and
distress to horses but in some outbreaks
can kill up to ten per cent of animals
infected. It can also be an economic
disaster for affected yards, which often
have to shut down for months.
How to recognise Strangles.
The severity of clinical signs can vary
depending on the age and condition of the
horse. Young horses are reported to often
be the worse affected.
The clinical signs are usually not seen
until 3-14 days after the horse has been
in contact with the infection. The initial
signs include the horse not appearing to
be its normal healthy self and a loss of
appetite. These signs are usually closely
followed by nasal discharge and in some
cases the development of a cough.
Swelling of the lymph nodes may
appear under the jaw or on the neck
approximately a week after the initial
clinical signs. These are abscesses, which
often burst discharging highly infectious
thick, yellow pus. In some cases these
glands may swell profusely, can restrict
the airway of the equine and it is from
86
this that the term
“strangles” arises.
Most affected
horses recover
uneventfully over a
period of about a
week with few cases
resulting in fatal
complications. More
severe cases will
take 3 – 4 weeks to
make full clinical
recoveries. Although
infection with S.equi
is usually restricted
to the head and
Parotid lymph node
neck, in a small
abscess.
proportion of cases
it may spread to
other parts of the
body where it causes abscesses and related
clinical problems. This condition is called
“bastard strangles” which has a poor
prognosis and is potentially fatal. Another
less common complication, which causes
bleeding into the gum and other organs
such as the lungs may also be fatal and is
referred to as “purpura haemorraghica”.
How is Strangles spread?
Strangles can be spread easily from horse
to horse, often leading to large outbreaks
with many horses becoming infected. The
infection can be spread by direct contact
between horses and via equipment shared
between horses ie. water troughs, feed
buckets, brushes and tack. The bacterium
will survive for long periods in water
troughs after an infected horse has taken a
Bastard strangles
drink from it.
Alarmingly, the disease can also be
transferred through handlers, farriers and
veterinary surgeons attending the animal.
Horses known as ‘carriers’ can spread the
disease for up to 8 months or longer, even
though they have recovered and appear
clinically healthy and normal.
It has been observed that many
outbreaks of ‘strangles’ occur after
the introduction of outwardly healthy
animals. It is now known that these are
‘carrier’ animals and are responsible for
starting new ‘strangles’ outbreaks.
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