Exercise Induced Collapse Syndrome (EIC) in Labrador Retrievers | |
Exercise Induced Collapse Syndrome (EIC) in Labrador Retrievers
Stephen W. Kendall - Alpharetta, Georgia
(This article originally appeared in the June-July 2009 issue of HUNTING RETRIEVER Magazine.)
I came across Exercise Induced Collapse Syndrome (EIC) for the first time around 2000 when two friends bought pups sired by a big time Field Champion and a dam with an Master Hunter title. A local dog trainer had recommended that they each buy a pup from this breeding, as he had trained and titled the dam of the litter and he really liked her. Well, both of these pups came down with EIC. It turned out to be a terrible tragedy and got my attention. I have never forgotten it, and neither have my friends!
Unfortunately there were no medical testing protocols for the disease at the time, so folks would breed their females to these big time studs and hope for the best. An unhappy consequence was the growth of EIC, which has since been recognized by the University of Minnesota via their testing program.
In August 2008 the Veterinary Diagnostic Lab (VDL) University of Minnesota EIC research team, in collaboration with the University of Saskatchewan and the University of California-San Diego, identified the EIC gene and developed a DNA testing program for the disease. The program took nearly a decade of work and comprehensive investigation by the teams of medical professionals at these institutions. Sources at the University of Minnesota VDL state that as of mid-March 2009 over 4,400 dogs have been tested. The bad news is that although this is not a random sample, the disease is reported to be widespread, with only 53 percent of the test dogs showing a NORMAL report.
What is Exercise Induced Collapse (EIC)?
The EIC researchers state that dogs affected with EIC can tolerate mild to moderate exercise, but 5 to 20 minutes of strenuous exercise with extreme excitement induces weakness and then collapse. Severely affected dogs may collapse whenever they are exercised; others only sporadically exhibit collapse episodes.
The first thing noted during an episode is usually a rocking or forced gait. The rear limbs then become weak and unable to support weight. Many affected dogs will continue to run while dragging their back legs. Some of the dogs appear to be uncoordinated, especially in the rear limbs. For a video on an affected dog you can go to the VDL website and view an actual event in progress (http://www.vdl.umn.edu/vdl/ourservices/canineneuromuscular/home.html).
Who Is Affected By It?
EIC researchers say the syndrome of Exercise Intolerance and Collapse (EIC) is being observed with increasing frequency in young adult Labrador Retrievers. Most, but not all, affected dogs have been from field trial breeding, but many conformation and pet dogs are also affected. Black, yellow and chocolate Labradors of both sexes are affected.
Signs first become apparent in young dogs, usually between 5 months and 3 years of age (average 14 months). In dogs used for field trials, this usually coincides with the age at which they enter heavy training. Littermates and other related dogs are commonly affected, but depending on their temperament and lifestyles they may or may not manifest symptoms. Affected dogs exhibiting symptoms of collapse are usually described as being extremely fit, muscular, prime athletic specimens of their breed, with an excitable temperament and lots of drive.
It is also noted that this disease is not just a product of the field trial bred Labrador Retriever. VDL states they have identified carriers in other retriever breeds, such as the Chesapeake and Curly Coat Retrievers.
EIC Is Hereditary
Littermates and other related dogs are commonly affected. Clinically unaffected dams and sires can unexpectedly produce litters with more than one affected dog, and pedigree analysis strongly supports an autosomal recessive mode of inheritance. This requires each parent to either be a carrier or an affected dog; i.e., a pup needs to get a copy of the EIC gene from each parent.
DNA harvested from the blood of affected dogs and their relatives was used to perform a full genome scan at the U of M in order to identify a genetic marker for EIC, and to find the genetic mutation causing EIC. In 2007 the chromosomal locus (site) of the mutation was found on chromosome 9, and the genetic mutation responsible for susceptibility to EIC was identified. This is a mutation in the gene for dynamin-1 (DNM1), a protein expressed only in the brain and spinal cord, where it plays a key role in forming synaptic vesicles containing neurotransmitters. DNM1 is not required during low-level neurological stimulation, but when a heightened stimulus creates a heavy load on release of CNS neurotransmitters (as with intense exercise, a high level of excitement and perhaps increased body temperature), DNM1 is essential for sustained synaptic transmission in the brain and the spinal cord.
Dogs symptomatic for EIC are rarely able to continue training or competition. It seems that if affected dogs are not exercised excessively, the condition will not progress and they will be fine as pets. Their ability to perform hunting requirements, especially Upland, dove hunting, etc., is questionable.
How Can I Be Assured That I Am Buying An EIC Normal Puppy?
When an EIC test is completed by the VDL, the results are sent to the owner of the dog.
1. The most reliable way to be assured that you are buying an EIC Normal pup is to have the EIC test done on the pup, or to verify that the sire and dam have both been tested and are rated EIC NORMAL. The second is to know if the sire and dam of the litter have produced an affected offspring in the past.
2. It is important to note that carrier dogs are physiologically NORMAL and do not appear to collapse according to the testing results at the VDL, and that a responsible mating of a NORMAL to a CARRIER would be your next best scenario, especially if you have no interest in breeding the pup. A NORMAL to an AFFECTED mating is considered acceptable by the VDL, with no chance of producing an AFFECTED puppy as long as one of the parents is clear (genetically normal). This type of mating, however, can produce a large percentage of carrier offspring.
3. Puppy testing can be done between the fifth and sixth week of age with Verified Permanent Identification (VPI), as long as the pup’s microchip or tattoo was verified by the veterinarian at time of testing. The VDL will be able to offer testing via a swab soon. This will make testing litters much more acceptable from both a practicable and financial perspective, so the breeder can test the litter prior to sending pups to their homes, and you will know for sure if your pup is Normal.
4. Important! You should know that just because a dog has never produced an affected pup in a litter, or a stud dog has never purportedly thrown an affected offspring, it does not mean that they are not carriers. It is possible to breed a hundred times and not produce affected pups. It is strongly recommended to not accept the testimony of a litter owner that the breeding is EIC clear unless you see test results. The breeder might not think they have produced affected pups because disabled pups were not reported back to them. Remember, this test has only been available since August of 2008.
How Can I verify the Results of the EIC Testing Status of the Sire and Dam or of My Puppy?
When an EIC test is completed by the VDL, the results are sent to the owner of the dog along with instructions for submission to the Orthopedic Foundation Of America (OFA). The OFA is a private non-profit foundation formed to collate and disseminate information concerning orthopedic and genetic diseases of animals, and to advise, encourage and establish control programs to lower the incidence of orthopedic and other genetic diseases.
The OFA maintains a list of all EIC NORMAL dogs as well as CARRIER and AFFECTED dogs, provided the dog’s owner sent the information given them from the VDL. The OFA is your most reliable source to verify and confirm the health clearances on a given litter. Simply go to the OFA website (www.offa.org) and input the registration number and/or name of the sire and dam of the litter to confirm test results.
In Summary
Breeding dogs is a serious process. It affects the lives and well being of both the pups and the families that end up with them. Breeders have an inherent responsibility to protect the comfort and well-being of the dogs they produce. Responsible breeders and the more progressive breed clubs, like UKC/HRC, are and have been responding to the challenge of improving the genetic health of our companions through the encouragement of better breeding practices and education of the public. Reporting health information to the OFA is a part of this inherent responsibility and many breeders subscribe to this philosophy.
Using very careful decision making, a breeder can breed a carrier/affected dog with a clean dog, provided full disclosure regarding potential carrier offspring is made to buyers. Breeders have choices and are encouraged to test litters that have a known carrier parent and to inform the pup buyers of the possibility that the puppy they are buying could be a carrier.
The puppy buyer is ultimately responsible to use their own resources and knowledge to find a litter that suits them. Health clearances are the single most important part of your due diligence investigation of the breeder and the litter. The OFA is your number one resource for health clearances, and CERF, PennHIP and CNM sites are also available. The bottom line is the buck stops with you and you are in charge of your own purse strings. When you interview a breeder, you owe it to yourself and your pup to be an educated consumer and spend money wisely. Remember that buying a puppy is also an investment of the heart over the course of hopefully 12 to 15 years, and you cannot put a dollar value on that.
A Final Word
This disease is not well known. Most veterinarians do not know about this disease; many breeders are still not aware of it either. If your HRC local club has a website, please do your part and establish a link to the website at the University of Minnesota’s Diagnostic clinic and provide a brief description of the disease on your website. Doing this will help educate folks and eliminate disease in the breed. Invite a veterinarian in to take blood samples at the next retriever club hunt test or training session and send the results in and encourage members to post the results at the OFA.
We humans are responsible for the spread of this disease in our wonderful companions. It will be up to us to fix the problem.
For detailed information go to the EIC website at the University of Minnesota. The Veterinary Diagnostic Laboratory’s mission is to protect and promote animal and human health through early detection and monitoring of animal diseases. The VDL fulfills its mission by identifying emerging diseases, developing new diagnostic methods, and training diagnosticians, veterinarians and graduate students. The laboratory is a part of the College of Veterinary Medicine and serves as Minnesota’s only full service accredited animal health diagnostic facility.
References:
• James R Mickelson, PhD, Professor, Veterinary Biosciences - University of Minnesota - 1988 Fitch Ave
St Paul MN 55108 - Phone: (612) 624-1246
e-mail: micke001@umn.edu
• Disclosure of financial interests: Drs. McCue, Mickelson and Valberg own the patent for PSSM genetic testing. A portion of the profit from testing goes to their ongoing research and patent royalties.
• Drs. Mickelson, Patterson and Taylor; and Minor, RN are the patent owners of the genetic test for EIC and a portion of the proceeds will go toward patent royalties. A portion of the proceeds from the test will be returned to the AKC Canine Health Foundation to further its mission to improve the health of all dogs.
• OFA (CHIC) Website. It’s for the health of the dogs.
About the author:
Steve Kendall has been a member of the Hunting Retriever Club since 1989. He purchased his first Labrador Retriever in February of 1986 and became involved in the local NAHRA program. Since then he has been involved in all aspects of the training, trialing and hunting of Labs from hunt tests to licensed field trials. From 1998 till 2004 he became involved in breeding his stud dog, and produced nearly 400 pups of which over 100 became titled, 80 in the UKC HRC program. Three became Grand Hunting Retriever Champions, all from his Yellow Labrador Retriever, HRCH Sundee’s Yukon Jack MH.
His favorite time is spent (when not at his home in Alpharetta, Georgia) hunting with his dogs. He can be found each fall in the marshes and woodlands near Waterhen, Manitoba hunting waterfowl and Ruffed Grouse with friends.
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In This Issue of Hunting Retriever Magazine...
"Exercise Induced Collapse Syndrome (EIC) in Labrador Retrievers
Stephen W. Kendall - Alpharetta, Georgia
|
In August 2008 the Veterinary Diagnostic Lab (VDL) University of Minnesota EIC research team, in collaboration with the University of Saskatchewan and the University of California-San Diego, identified the EIC gene and developed a DNA testing program for the disease. The program took nearly a decade of work and comprehensive investigation by the teams of medical professionals at these institutions... the disease is reported to be widespread, with only 53 percent of the test dogs showing a NORMAL report.
What is Exercise Induced Collapse (EIC)? The EIC researchers state that dogs affected with EIC can tolerate mild to moderate exercise, but 5 to 20 minutes of strenuous exercise with extreme excitement induces weakness and then collapse...
Read more here
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