vWD (von Willebrand’s Disease)

All NyaStar Irish Red and White Setters (or their parents) are DNA Tested CLEAR for vWD.

What is Von Willebrand's disease?

Von Willebrand's is an inherited disease that decreases the blood clotting ability in dogs. The symptoms of von Willebrand's disease in dogs are somewhat similar to the symptoms displayed by humans suffering from haemophilia A.
The best way of preventing von Willebrand's disease is to never allow any dogs with von Willebrand's disease to breed. In order to achieve this, all dogs need to be tested for von Willebrand's disease prior to breeding. Since this is a congenital disease, it will become much less common if all breeders test their dogs.

Von Willebrand's disease symptoms in dogs

Von Willebrand's is a congenital disease that often manifests when the puppy is still very young. A haemorrhage will cause suspicion of von Willebrand's disease and it is often diagnosed after a spaying or neutering procedure. In dog breeds where von Willebrand's disease is common, many veterinarians will carry out a screening test before doing any planned surgery on a dog from such a breed.

In dogs with borderline von Willebrand's factor, vaccination can cause a slight decrease of platelet function. The same is true for treatments with an non-steroidal anti-inflammatory drug (so called NSAID:s). If this happens, the symptoms will be unusual bruising and/or bleeding. This sudden drop in platelet function is only temporary.

Von Willebrand's disease testing for dogs

Two different methods are used for von Willebrand's testing: von Willebrand's blood test and von Willebrand's DNA test. Blood testing is the classical method of detecting this disease in dogs; the von Willebrand's factor is measured in a blood sample from the dog and compared to the result of other dogs. The result is expressed in a percentage, and it is therefore possible for your dog to get a result over 100%, e.g. 120% or 160%, if it has a von Willebrand's factor that is much higher than the standard result. If the result is up to 49%, the dog is an affected or genetic carrier of von Willebrand's disease. If the result is 50-69%, the dog is a borderline case. Results between 70% and 180% are all considered normal.  DNA testing is the only definitive answer for carrier status.

Von Willebrand's disease treatment for dogs

In situation where the dog will bleed, such as surgery, it is possible to administer von Willebrand's factor to the dog via a transfusion. Von Willebrand's factor can also be given to the dog to stop accidental bleeding. It is not possible for veterinarians to obtain pure von Willebrand's factor, but they do have access to a blood product called cryoprecipitate that is very rich in von Willebrand's factor. A cryoprecipitate transfusion will make a significant difference in the dog during approximately 4 hours after each transfusion. In cases where the veterinarian has no cryoprecipitate, the second best choice is complete plasma.

A hormone named desmopressin acetate (DDAVP) has been shown to cause a sudden emission of von Willebrand's factor into the dog’s bloodstream and can therefore be helpful for dogs suffering from von Willebrand's disease. When a dog suffering from von Willebrand's disease gets a shot of DDAVP the bleeding time will be decreased for roughly 2 hours after the 30 minute long onset period.

 

To order test kits please contact the Animal Health Trust in the United Kingdom at DNATESTING@aht.org.uk