Pug Dog Encephalitis (PDE)
There is no cure for PDE. Unfortunately very little is known about this disease. What is known about PDE is it's an inflammation of the brain. It is noted that it strikes Pugs up to the age of 4 years---More common in females than in males It is a belief that it is a genetic disease Seizures can be from a few seconds to a few minutes. Seizures cannot be maintained by the use of medications. Some dogs even have temporary remissions. Seizures are the main symptom of PDE although PLEASE NOTE THAT VERY FEW PUG SEIZURES ARE ACTUALLY CAUSED BY PUG DOG ENCEPHALITIS. They could suffer from Epilepsy, gasses, low blood sugar, exposure to toxic chemicals, or any other unknown causes.
What to Watch For:
• Walking in circles before or in between seizures
• Pressing their heads against the wall, furniture and or people
• A staggering walk
• Apparent blindness
• Neck pain
• Sudden Death
• Agitation or Aggression
• Lethargy /Listlessness (Lethargy can mean many things check with your veterinarian)
• Loss of muscle coordination (this can also indicate other problems such as neurological issues and a side effective to convulsive activity brought out by inner ear disturbances Generally affects litter mates and closely related dogs. PDE can only be positivelydiagnosed by an autopsy on the brain stem. Your vet may do routine blood work and urinalysis to check for encephalitis although it is rarely diagnosed this way. Chest x-rays, abdominal ultrasound or lymph node aspirates may find signs of an infection; however, many animals with encephalitis will not have systemic abnormalities. Therefore, encephalitis is usually diagnosed by a spinal tap. A spinal tap will tell exactly what is going on inside the nervous system. A significant increase in white blood cells in the spinal fluid usually indicates encephalitis. Spinal fluid is usually collected at the base of the skull in cases of suspected encephalitis.
2 Classifications of PDE:
This classification of PDE features seizure activity and sometimes the additional symptoms preceding the seizure activity. The seizures will strike, last anywhere from just a few seconds to a few minutes and then recur in a matter of days or weeks. In between these seizures, the Pug will return to normal and demonstrate no symptomatic characteristics associated with PDE.
This classification of PDE features seizure activity that is often more frequent, but not always. In between the seizure activity however, the Pug does not return to normal but instead does demonstrate symptomatic characteristics associated with PDE. These characteristics between seizures are commonly depression, bewilderment, disorientation and signs of lacking muscular coordination such as having difficulty walking. The end result of either classification of PDE unfortunately is the same. Whether it strikes in the slow progressive or the rapid progressive form, PDE will eventually kill the Pug. Those Pugs that have been diagnosed with PDE and said to have survived are believed to have been misdiagnosed, or not diagnosed conclusively.
A term used when an infectious cause can't be found. In many cases of idiopathic encephalitis, an underlying immune-mediated cause is suspected because these animals improve after suppression of the immune system. Immune-mediated diseases occur when the body's white blood cells mistakenly attacks normal tissue, in this case brain or spinal cord. There have been a number of different types of idiopathic encephalitis described in dogs
Susceptibility to Pug Dog Encephalitis (PDE)
Approximately 1. 2% of Pug dogs die of necrotizing meningoencephalitis (NME), also known as Pug dog encephalitis (PDE). NME is an inflammatory disease of the central nervous system that is usually progressive and fatal. Symptoms of NME include seizures, depression, ataxia, abnormal gait and blindness (1). Female, fawn-colored Pug Dogs younger than 7 years of age are more apt to develop NME than older, male and non-fawn colored individuals (2). Recent research has revealed that susceptibility to NME is associated with the dog leukocyte antigen (DLA) region of dog chromosome 12 (3). The association is at or near the region containing the DLA class II genes. Dogs that have two identical copies of the NME associated markers in this region, have an observed risk (OR) of 12.75 for NME in their lifetime over Pugs that have only one or no copies of these markers (OR 0-1.08).
Results reported as:
N/N - No copies of the NME associated markers (homozygous for normal). These dogs have a low risk of developing NME.
N/S - One copy of the NME associated markers (heterozygous for susceptibility). These dogs have a low risk of developing NME.
S/S - Two copies of the NME susceptibility associated markers. These dogs are 12.75 times more likely to develop NME in their lifetime.
Outcomes of matings based on NME test results:
1. N/N x N/N = all puppies will have two copies of the low NME risk markers (N/N) and will have a significantly reduced risk of developing NME during their lifetime.
2. N/N x N/S = One half of the puppies will have two copies of the low NME risk markers (N/N), and have a significantly reduced risk of developing NME during their lifetimes. One half of the puppies will carry one copy of the susceptibility markers (N/S), but will also be at low risk for developing NME.
3. N/S x N/S = One fourth of puppies will be N/N and at low risk for NME; one half will be N/S, carry the susceptibility marker, but will also be at low risk for NME; one fourth will be S/S and will be at high risk for NME.
4. N/S x S/S = One half of the puppies will carry the susceptibility marker (N/S), but will not be at increased risk of NME; one half of the puppies will have two copies (S/S) of the susceptibility marker and be at high risk of NME.
5. N/N x S/S = All of the puppies will carry one copy of the susceptibility markers (N/S), and be at low risk for developing NME.
6. S/S x S/S = All of the puppies will carry two copies of the susceptibility marker (S/S) and be at high risk for NME.
Notes: This is not a diagnostic test for NME in Pug Dogs or for NME disease or risk in other breeds. The test is only to determine risk for developing NME in Pug Dogs and for selecting matings that will produce puppies that are at decreased risk (N/N, N/S). Although a significant proportion (11%) of Pug Dogs is S/S, only about 1 in 8 of this group will develop NME during their lifetime.
Also, breeders are advised against breeding out the S genotype, because 40% of Pug Dogs have the S genotype in a heterozygous (N/S = 29%) or homozygous state (S/S = 11%). Eliminating the S genotype will lead to a considerable loss of genetic diversity. Therefore, breeders should carefully select matings that do not produce S/S puppies.
The NME report includes DNA types for a panel of 8 markers selected from the International Society of Animal Genetics (ISAG) canine parentage panel. These markers provide individual identification for each sample tested.
1. Talarico LR, Schatzberg SJ. Idiopathic granulomatous and necrotising inflammatory disorders of the canine central nervous system: a review and future perspectives. J Small Anim Pract 2010: 51: 138–149.
2. Levine JM, Fosgate GT, Porter B et al. Epidemiology of necrotizing meningoencephalitis in Pug dogs. J Vet Intern Med 2008: 22: 961–968.
3. Greer KA, AK Wong, H Liu, TR Famula, NC Pedersen, A Ruhe, M Wallace and MW Neff. Necrotizing meningoencephalitis of Pug Dogs associates with dog leukocyte antigen class II and resembles acute variant forms of multiple sclerosis. Tissue Antigens 2010: 76:110-118.