Picture Belgian draft horse
Picture Shire horse
Picture Clydesdale
 CHRONIC PROGRESSIVE SWELLING, HYPERKERATOSIS AND
FIBROSIS OF DISTAL LIMBS IN CLYDESDALES, SHIRES AND
BELGIANS SUGGESTIVE OF CHRONIC LYMPHEDEMA.
 RESEARCH PROJECT
 HOW TO SUPPORT THE PROJECT
 CONTACT INFORMATION
 PUBLICATIONS
 PROJECT SECURED AREA
 CHRONIC PROGRESSIVE SWELLING, HYPERKERATOSIS AND
FIBROSIS OF DISTAL LIMBS IN CLYDESDALES, SHIRES AND
BELGIANS SUGGESTIVE OF CHRONIC LYMPHEDEMA.
A condition characterized by progressive swelling, hyperkeratosis and fibrosis of distal
limbs has been recognized in Shires, Clydesdales and Belgian Draft horses. This chronic
progressive disease starts at an early age, progresses throughout the life of the horse and
often ends in disfigurement and disability of the limbs which inevitably leads to the
horse’s premature death. The pathologic changes and clinical signs closely resemble a
condition known in humans as chronic lymphedema or elephantiasis nostras verrucosa.
The lower leg swelling is caused by abnormal functioning of the lymphatic system in the
skin, which results in chronic lymphedema (swelling), fibrosis, a compromised immune
system and subsequent secondary infections of the skin. Based on preliminary research, it
appears that a similar pathogenic mechanism is involved in the disease that affects these
specific draft horse breeds. Te clinical signs of this disease are highly variable. The
earliest lesions are characterized by skin thickening and crusting; both are often visible
only after clipping the long feathering. Secondary infections develop very easily in these
horse's legs and usually consist of either chorioptic mange or bacterial infections. Both
dark and white skin on the lower legs are equally affected. These lesions are consistent
with pastern dermatitis, a process also seen in other breeds. In Shires, Clydesdales and
Belgians however, these lesions do not respond well to therapy. As the condition
becomes more chronic, the lower leg enlargement becomes permanent and the swelling is
firm on palpation. More thick skin folds and large, poorly defined, firm nodules develop.
The nodules may become quite large and often are described as "golf ball" or even
"baseball" in size. Both skin folds and nodules first develop in the back of the pastern
area. With progression, they may extend and encircle the entire lower leg. The nodules
become a mechanical problem because they interfere with free movement and frequently
are injured during exercise. This disease often progresses to include massive secondary
infections that produce copious amounts of foul-smelling exudates, generalized illness,
debilitation and even death.
Picture early lesion
Picture chronic lesion
Picture distribution lesion
 RESEARCH
For the last two years, a Center for Equine Health scientific team, led by Dr. Hilde De
Cock and Dr. Verena Affolter, has been studying this disease. They have employed
several different investigative techniques in an attempt to find the underlying cause of
this serious and debilitating disease. These researchers utilized histopathologic and
radiographic imaging techniques to examine the skin, blood and lymph flow of the distal
limbs of normal and affected draft horses. Detailed examinations of tissues from
pathological specimens and skin biopsies were conducted using several different
methodologies in an attempt to define and delineate the basic pathogenic features of the
condition. This research team now understands that this condition is primarily a
lymphatic disease, and that the pastern dermatitis that draft horse owners have been
struggling with for years is a secondary result due to the body's inability to properly
remove fluids and oxygenate the skin of the lower leg. We know that the lymph system
breaks down over time and that protein-rich fluid leaks into the tissues of the lower leg,
which results in fibrosis of the tissues under the skin and thickening of the skin itself.
The clinical signs and pathologic changes resemble closely a condition known in humans
as chronic lymphedema or elephantiasis nostras verrucosa. In order to develop a
successful treatment or management strategy for these horses the research team recently
started a thorough research project in cooperation with Professor Barry Starcher from the
University of Texas Health Center at Tyler, Texas, USA and Professor Richard Ducatelle
from The University of Gent, Merelbeke, Belgium. The project is generously sponsored
by …………..GREG, SHOULD WE MENTION THE SPONSORS?????????
In the next couple of years this group of researchers will focus on developing better
diagnostic tools to detect the disease in the early stages, and concurrently significant
effort will be put in complete characterization of the disease and better understanding of
the pathogenic mechanism underlying this disease.
 HOW TO SUPPORT OUR RESEARCH
SAMPLES
MONEY
 CONTACT INFORMATION
Additional information can be obtained from the following persons:
Dr. Hilde De Cock: hedecock@ucdavis.edu
Dr. V. Affolter: vkaffolter@ucdavis.edu
Dr. G. Ferraro: glferraro@ucdavis.edu
LINKS
Link to horse report Volume 21, Number 2, April 2003
Link to horse report Volume 21, Number 2, April 2003
 PUBLICATIONS
1. Van den Eynde H. The Belgian Draft Horse has Painful Limbs (Belgisch trekpaard heft
zere benen). Science section of a Belgian newspaper "De Standaard" 2002; November 29.
2. Verstraete J. The Belgian draft horse in danger (Belgisch trekpaard bedreigd). Gent
Universiteit 2003;17(4):26-29.
3. De Brauwer P. Health status of the limbs of Belgian draft horses (Gezondheid van de
benen van trekpaarden). Landbouwleven February, 14th, 2003.
4. Equus
Scientific papers:
De Cock et al. Progressive swelling, hyperkeratosis and fibrosis of
distal limbs in Clydesdales, Shires and Belgian draft horses suggestive of
primary lymphedema" accepted in Lymphatic Research and Biology, Vol. 1
# 3.
 PROJECT SECURED AREA
Will only be accessible by Hilde De Cock, Verena Affolter, Greg Ferraro, Jim
MacLachlan, Leen Vanbrantegem and Barry Starcher
Will contain space for input new data and space for downloading most recent data.