health issues specific to the pwd breed
Generally speaking, this breed is relatively healthy and many live well into their teens. Nevertheless, there are a few health issues and diseases that are found in the breed and for which good breeders will test when tests are available. PWD breeders and a variety of researchers have combined efforts via The PWD Foundation to investigate a number of health issues that affect PWDs, as well as other breeds, and these investigations often yield new marker tests for breeders to use and/or new treatment protocols. The statistics for many of these diseases are available on the OFA website under breed specific statistics ((https://www.ofa.org/diseases/breed-statistics#detail)). Be award that OFA statistics may be over-estimates because of the small sample sizes of dogs reported. These diseases include:
- Hip Dysplasia, where the hip joint is improperly formed such that the head of the femur does not fit snugly into the acetabulum of the sacral bone. Hip dysplasia is a complex issue that has both genetic and environmental components and can be excerbated by overfeeding puppies and adolescents and letting them run on slippery surfaces when very young. Approximately 13% of PWDs will be diagnosed with some level of hip dysplasia.
- Elbow Dysplasia is caused by growth disturbances in the elbow joint that lead to a mismatch of growth between the foreleg bones (radius and ulna) between the elbow and wrist. This growth mismatch may be due to defects in cartilage growth, trauma, genetics, exercise, and diet during puppyhood. Approximately 1.8% of PWDs will be diagnosed with elbow dysplasia.
- Progressive Retinal Atrophy is a genetic disease in which the cells of the retina degenerate over time and cause blindness. Currently we have two forms, a late onset prcd form and an early onset form; both of these forms have a genetic test that can be conducted on breeding dogs. Approximately 14.2% of PWDs are carriers for prcd-PRA; 0.1% of PWDs are affected by EOPRA, whereas 1.3% are carriers.
- Storage Disease (GM1 gangliosidosis), a recessive genetic disease that causes a toxic build up of substances in nerve cells because of a lack of an enzyme. Dogs affected by this disease show progressive neurological deterioration and generally die before their first year. Approximately 0.3% of PWDs are carriers for GM-1.
- Juvenile Dilated Cardiomyopathy (JDCM), a fatal recessive genetic disease, causing death as early as 5 weeks of age or any other time during the first year of life. Approximately 2.8% of PWDs are carriers for JDCM.
- Follicular Dysplasia is a genetic disease in which the hair follicles are dysplasic and the hair falls out, particularly on the torso. It is sometimes seen in curly to curly matings.
- Addison's Disease is the result of a deficiency of adrenocortical hormones. If caught and treated, dogs with this disease can live normal lives, although they may not be able to handle stress very well. It is thought that Addison's disease is heritable as a recessive allele with a frequency of 0.49 and a breed occurrence rate of 1.5%. However, estimates of dogs affected in the population range from 24% to 12.8%. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1481556/)
- Cushing's Disease, the opposite of Addison's; this occurs when the adrenal glands overproduce cortiosteroid hormones. It can lead to elevated blood sugar (eventually diabetes) and blood pressure, extreme hunger and thirst, thinning of skin and coat, loss of muscle mass, irritability and restlessness, as well as having secondary impacts on the thyroid gland, that can result in hypothyroidism.
- Hypothyroidism is the result of the thyroid failing to produce sufficient thyroxine to properly fuel metabolism. There are two ways the thyroid can malfunction: via an immune system disorder known as autoimmune thyroiditis, where the body attacks the tissues of the thyroid gland, the gland responds by over-secretion, and eventually the gland becomes depleted or via the body simply producing less thyroid hormone over time, and eventually not enough for normal biological processes. General symptoms include weight gain, lack of energy, dull coats, excessive shedding, flaky skin, ear infections, and behavioral changes such as incessant whining, nervousness, fear in the presence of strangers, hyperventilating, disorientation, and failure to be attentive. These changes can progress to sudden unprovoked aggressiveness in unfamiliar situations with other animals, people and especially with children. Hypothyroidism can be treated by administering synthetic thyroxine daily. Approximately 3.9% of PWDs are affected by thyroid issues.
- Inflammatory Bowel Disease (IBD) occurs when the lining of the dog's intestinal tract hosts an unusually high number of inflammatory cells and these cells inhibit the normal absorption and passage of food. Chronic vomiting and diarrhea with blood or mucus are common symptoms, along with lethargy, weight loss, and depression. Any number of variables may contribute to the development of IBD including genetics, food allergies, parasites, bacteria or an abnormal immune system. Genetics is thought to play a role, but mode of inheritance is unknown. Reported incidence of IBD by owners is 1.9% (2014 PWDCA Health Survey).
- Chondrodystrophy (CDDY) is a condition where the discs between the vertebrae develop abnormally such that the pulp area of the disc becomes hardened and may even convert to cartilage and then ossify. These degenerated discs are then susceptible to herniation. Dogs with N/CDDY or CDDY/CDDY genotype will have leg shortening compared to N/N dogs and intervertebral disc disease (IVDD), and are at risk for intervertebral disc herniation. The gene is dominant so is expressed whether the dog has one copy of it or two. Two copies seem to act in an additive fashion meaning that leg shortening and disc degeneration is enhanced compared to a single copy. Multiple factors are thought to influence whether a particular disc herniates in an individual dog and current suggestions are to keep your dog very lean and not do activities like agility or dock diving that would torque the body. Disc herniation will result in severe pain and may also result in paralysis. According to OFA, about 20.6% of PWDs are N/CDDY and 1.2% are CDDY/CDDY.
- Renal Dysplasia is a condition where the kidney glomeruli fail to develop properly and remain in an embryonic condition. Renal failure can result, often with loss of protein in the urine. Vomiting, weight loss, anorexia, lethargy and muscle weakness are typical signs, along with selective appetite, poor hair coat, and dilute urine with little color or odor. Secondary urinary tract infections may occur. Often mislabeled "juvenile RD", it can affect puppies early on or slowly affect adults, depending on how much of the kidney is underdeveloped. Affected puppies may leak urine, which owners sometimes misinterpret as a house-training problem. A chemical odor may be detected in the breath due to metabolic wastes not being properly excreted by the kidneys. It is a dominant disease, which means that carriers can be affected and develop renal failure; however, it has low penentrance such that only 5% of carriers are affected.
- Puppy Eye Syndrome/Microphthalmia Syndrome, is a set of disorders displayed very early in life that generally combine microphthalmia and stunted growth; often low platelet counts are found within affected dogs. The puppies with this syndrome do not thrive compared to normal puppies and often die at a young age. Mode of inheritance is via a recessive allele. Females seem to be more affected than males within a litter. Approximately 5.4% of PWDs are carriers for this syndrome.
- Cataracts are any opacity within a lens. The opacity can be very small (incipient cataract) and not interfere with vision, can involve more of the lens (immature cataract) resulting in blurred vision or can impact the entire lens causing blindness (mature cataracts). Mature cataracts can morph into hypermature cataracts which cause the lens to shrivel and the lens capsule to wrinkle. Cataracts can have a genetic basis and an age-related basis. OFA CAER exams help to identify these two forms and should be performed on all breeding dogs prior to breeding, as well as on pet dogs several times throughout their lifetime.
- Cancers, generally hemangiosarcoma, lymphodema, lymphosarcoma, osteosarcoma, mast cells tumors, mammary tumors, etc. Reported incidence of cancers in PWDs from owners is 6.2% (2014 PWDCA Health Survey).