PG.18
AQHA VET NEWS
Tetanus is a preventable disease, but a
2018 Australian survey discovered that
over 25% of owners don’t vaccinate
their horses, 48% of older horses in
Queensland remain unvaccinated and
only 2 out of 41 pony club families
vaccinated their horses to protect them
against tetanus. Statistics from England
and Ireland revealed similar vaccination
rates. The Pony Club Manual advises
tetanus prevention via vaccination of
horses and riders. The Australian Horse
Welfare Protocol states that vaccination
should be routine.
Horses that develop tetanus have a
better prognosis if vaccinated within
1 year prior to sustaining the wound.
When a horse is not up-to-date on their
vaccination and gets a foot abscess or
a wound, a booster should be given
immediately.
The disease tetanus progresses very
quickly and by the time an injury is
detected and antitoxin administered it
may be too late. Most importantly, in
many cases of tetanus no known injury has occurred or the
initial wound/the source of infection cannot be found and may
be almost completely healed before symptoms occur. The
early stages of tetanus can look like colic, laminitis or tyingup
which can delay correct diagnosis - so if your horse is not
vaccinated and shows any signs of disease (Table 1), seek
prompt veterinary advice.
The toxoid vaccine is not immediately effective and takes at
least 2 weeks for the horse’s immune system to fully respond.
In some instances an anti-toxin may be administered. The
anti-toxin binds to circulating toxins and prevents them from
attaching to nerve endings. It is not as effective as the vaccine
and should not be relied on for any sort of protection.
Administering the anti-toxin to protect an unvaccinated horse
that has an injury only protects the horse for 10 days, only
inactivates the toxins that haven’t yet reached the nervous
system – and is not 100% effective in preventing the progress
of the disease.
A single vaccination does not always confer immunity and
individual horses vary in their immune response. The optimal
frequency of revaccination has not been established. In humans,
unless an injury has occurred, it is currently recommended that
people receive a toxoid booster every 10 years. Horses are more
susceptible to tetanus and all horses should be vaccinated for
tetanus as recommended by their veterinarian. The vaccination
protocol varies according to the age and status of the horse.
Foals from unvaccinated mares require a different vaccination
program to foals from vaccinated mares, as do brood mares,
adult vaccinated and unvaccinated horses. Revaccination is
recommended on the occurrence of wounds or before surgical
procedures.
Tetanus is rarer now due to vaccination and improved medical
management of wounds. The reduction in cases, however,
is not due to a reduction in the number of environmental
bacteria and every unvaccinated horse is still at risk. Although
antiseptic surgical procedures and correct treatment of wounds
are important in tetanus prevention, one cannot be certain
that all spores from the wound have been eliminated – once
spores have lodged in the tissues of the horse, even a bump or
bruise months later can damage tissue and create favourable
conditions for the spores to germinate and begin producing
toxins.
There is no more horrible yet easily preventable disease than
tetanus. Nonchalance is an avoidable risk. Horses are the most
vulnerable species and as excellent vaccines are available,
every horse should be vaccinated.
www.jenquine.com
AUSTRALIAN QUARTER HORSE ASSOCIATION - WWW.AQHA.COM.AU