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WORKING ON STRANGLES’ LAST GASP
by Cathy L. Smith
When talking with Dr. John F. Timoney of the
UK Gluck Equine Research Center about strangles, one can get
a true idea of how many-faceted the study of one disease can
be. While most believe disease research delves only into finding
cures for illnesses, Dr. Timoney, and other infectious disease
researchers like him, is quick to point out there are many
questions that need to be answered before—and after—a
cure is found. The cure is the goal, he asserts, but the information
collected on the way is invaluable for continued research
into the spotlighted illness or other diseases.
Timoney began his work on a vaccine for strangles
when he was employed at Cornell University. He then moved
to the Gluck Center in 1992 and brought his strangles expertise
with him. He has continued his work on the vaccine, trying
to perfect its performance and finding just the right way
to administer it.
Timoney explains that strangles is a highly
contagious disease of the tonsillar complex found in the horse’s
nose and jowl and caused by the bacteria Streptococcus equi.
It is seen primarily in young horses and can be life-threatening
to very young foals. A horse owner would see a depressed animal
with a depleted appetite, having a temperature of 103°
or more, and possibly some watery nasal discharge. In short
order, the nasal discharge becomes a purulent excretion, and
there is swelling of the jowls and the throat area. Breathing
may be labored. What’s happening is that any one of
the seven tonsils horses possess--or any combination of them--are
infected. The tonsils, which are lymph nodes, swell and develop
abscesses that will eventually break open. The abscesses may
crowd the trachea, making breathing difficult and swallowing
uncomfortable—hence the name of the disease. The horse
will lose condition and be unusable for three or four weeks
while it recovers. Occasionally, an open abscesses will spill
the bacteria to other parts of the horse’s body, causing
an extended illness.
The good news about strangles is that it is
rarely fatal and the bacteria cannot “live in the environment.
A horse may be able to recover without treatment. But, Timoney
said, it takes time to cure, and a sick horse is a threat
to the health of any other horse, burro or mule which it may
come in contact with.
Just how the bacteria gets into the tonsils
and how is causes the disease are only two facets that will
be addressed by his research. Once these questions are answered,
Timoney feels it will be easier to prevent or stem an outbreak.
Right now, there are several vaccines for strangles available,
but exactly how effective they are is still being debated.
Timoney said ideally, he would like to see
a vaccine that only uses the components of the bacteria that
will speed the horse’s body into producing the antigens
necessary for immunity rather than using a solution with live
or modified-live bacteria, as in the currently available vaccines.
Just which parts of the bacteria would allow this to happen
is another facet of Timoney’s investigation into the
mystery of strangles. He also wants to discover which is the
best method with which to administer the vaccine. Timoney
favors the intranasal application because, he said, it applies
the vaccine directly to the area that would be attacked.
Another facet that Timoney hopes to uncover
in his quest is how the vaccine’s protective immunity
works, once it is viable.
Besides assisting veterinarians and horse
owners, Timoney feels his work will benefit other infectious
disease researchers at the Gluck Center and elsewhere who
are conducting their own investigations into related equine,
feline, and porcine illnesses. And even though humans cannot
become infected with S. equi, human medicine may benefit from
his findings since a somewhat similar condition in people
is strep throat.
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