Watch Out for this Mysterious Equine Disease
Posted December 20, 2018
horses in a narrow region of Texas have developed a condition known
as nasopharyngeal cicatrix, which causes scarring of the upper
airway. Researchers believe this disease is the result of an
environmental agent, but no one knows for sure what causes it or
why it is so localized.
Dr. Canaan Whitfield, an assistant professor of large animal
surgery at the Texas A&M College of Veterinary Medicine &
Biomedical Sciences who has seen many horses with this condition,
explains some of the symptoms horse owners can watch out for.
“Symptoms are variable and depend on the stage and severity of
disease,” Whitfield said. “In early stages, you might see nasal
discharge, coughing, difficulty swallowing, and other similar
He compared the early stages of nasopharyngeal cicatrix to
pharyngitis, commonly known as a sore throat, in humans. Because
these early symptoms are mild, they often go unnoticed by owners;
however, nasopharyngeal cicatrix is progressive and if not caught
early, it can lead to serious health issues.
“Once the early stages have passed, scar tissue begins to form,”
Whitfield explained. “This scar tissue can be small and cause no
signs or it can be large and start to obstruct airflow.”
He said that if airflow is obstructed, owners may hear a strange
noise when the horse is breathing, especially when it is
exercising. If the scarring becomes severe enough, the horse will
eventually become unable to breathe.
Nasopharyngeal cicatrix is most commonly seen in Central and
Southeast Texas, according to Dr. Michelle Coleman, an assistant
professor of large animal internal medicine at the CVM.
Whitfield and Coleman see multiple horses with this disease
every week at the Texas A&M Large Animal Hospital. They say it
is often diagnosed as an incidental finding when horses are being
seen for other health concerns.
The mystery of this disease is that the cause is still unknown,
despite all the research that has been done. According to
Whitfield, most of this research was done by Dr. Tracy Norman, a
former CVM internal medicine specialist.
“She showed that horses that live exclusively outside are more
at risk, as compared with horses that are stalled for significant
amounts of time,” Whitfield said. “This suggests to me that the
cause is environmental and likely something in the pasture.
“Beyond that, we really do not know,” he said. “We are looking
at various fungal and bacterial causes but have not yet nailed down
Unfortunately, because the cause is unknown, there is not an
effective prevention strategy or treatment method for
nasopharyngeal cicatrix. Whitfield said that many
products—including antifungal vaccines, antimicrobials, and
anti-inflammatory drugs—have been used in an attempt to treat the
disease, but none have been proven successful.
Coleman said the only option for horses with severe cases is a
permanent tracheostomy, a procedure in which the horse is given an
alternative airway through the trachea.
Reducing pasture time may help lessen the chance that a horse
will get nasopharyngeal cicatrix, but this can lead to other
problems such as sand ingestion and colic, according to
Nasopharyngeal cicatrix may be causing problems now, but
Whitfield believes a cure will be found in the near future. He said
determining the cause of the disease is the key to finding a way to
“Once we know the cause we can develop effective prevention
strategies,” he said. “It is going to take time and money but I
think we can get there.”
While researchers work toward understanding the cause and
developing a treatment, horse owners can help protect their horses
by keeping up with regular veterinary check-ups, watching for early
symptoms, and developing a plan for health emergencies.
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