For Horse Owners and Veterinarians
Vol. 17, Issue No. 2 – 2014
PURDUE UNIVERSITY COLLEGE OF VETERINARY MEDICINE
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Equine Gastric Ulcer
Syndrome (EGUS) . . . .pg. 6
Pleuropneumonia . . . .pg. 1
Zoonotic Disease . . . . .pg. 4
Lungworms . . . . . . . . . .pg. 3
News & Notes
Horseman’s Forum. . . .pg. 7
New LA Surgery Resident
– Alec Davern . . . . . . . .pg. 2
New LA Surgery Fellow
– Jesus Hermida . . . . . .pg. 2
EGUS ..............pg. 6
Pleuropneumonia in Horses
By Dr. Sandra D. Taylor DVM, PhD, Dipl. ACVIM,
What puts your horse at risk?
Purdue Large Animal Internal Medicine Service
Pleuropneumonia refers to infection of the lungs (pneumonia) that leads to infected
fluid accumulating in the space between the lungs and the body wall (pleuritis). This is
a very serious disease in horses that can lead to death, and survival rates are much better
when the disease is detected early and treated aggressively.
There are several known risk factors for development of pleuropneumonia, including:
Upper respiratory tract viral infections
Viruses such as influenza (flu), herpes virus (EHV-1, EHV- 4), rhinovirus and equine
viral arteritis virus (EVA) can infect upper respiratory tract epithelial cells that line
the nasal passages, throat and upper airways. These infections often cause high fevers,
a decreased appetite, and occasionally cough or nasal discharge. These viruses can
damage the hair-like projections (cilia) that line the upper airway, which prevents
clearance of inhaled organisms and debris. This can allow secondary bacterial
pneumonia, since the bacteria is not removed in an appropriate fashion by the cilia.
Long trailer rides
Even the cleanest trailers have relatively poor ventilation, which means that your
horse may inhale a high amount of dust, hay mold and aerosolized components
of manure during a trailer ride. Also, many horse’s heads are tied up in the trailer,
which prevents drainage of inhaled particles that are normally trapped in mucus
that drains out when the horse’s head is down. This allows increased entry of normal
bacterial flora (from the throat) and environmental bacteria into the lungs.
With intense exercise, the immune system may be compromised. Studies have
shown that high-intensity exercise can decrease white blood cell function, which
can predispose horses to infection. In addition, horses may aspirate more debris
during exercise, especially racehorses.
Many horses are kept in barns with other horses, and trailer to shows/events with
other horses. Just like with people cooped up in small areas, this increases transfer
of infectious agents (such as the flu virus) between horses.
Immune function can be decreased by stress hormones (e.g. cortisol). Stress can
be caused by several things, including transport, exercise, shows/events, pregnancy,
lactation, and training.
(continued on pg. 2)