Animalia Life

The Breed History
Records of this breed go back as far as 400 BC. The breed ancestors may have been Tibetan Mastiffs and later, Pomeranian stock brought over from China. Originally exported to Holland, it is possible that the breed name derives from the word applied to pet monkeys, "pug". They were considered to have similar facial expressions as Marmosets. Another possible source for the name is the term "pugnus", which is Latin for fist, presumably reflecting their very round head. These dogs became popular with English royalty. First registry for Pugs with AKC registry occurred in 1885.

Breeding for Function
Bred solely for companionship.

Physical Characteristics
Height at Withers: 10-11" (25-28 cm)
Weight: 14-18 lb (6.5-8 kg).
Coat: The fine short double glossy coat lies flat and breed colors include fawn and apricot, black, and silver. Markings follow a set pattern and are black or dark including ears, muzzle and sometimes a line is present down the back.
Longevity: 13-15 years.
Points of Conformation: Their cobby, stout, and compact square constitution gives them a lot of apparent substance for their size. Though they are classed as a toy, their heavy build makes them look larger. The head is massive and round, the high set ears are soft, the leather is thin and ears either in a rose or button type. Muzzle is very short and square and the bite is mildly undershot. Top of the head has prominent forehead wrinkles, eyes are dark, shallow set, and very large. Neck is short and strong, topline level, the thorax is barrel shaped, tail is high set and ideally, doubly curled to rest tightly over the hip joint. Legs are straight, moderate in length, and feet are moderately sized and oval in shape, toenails are black and dewclaws are generally removed. Their gait is strong, free, and hindquarters typically have some roll.

Recognized Behavior Issues and Traits
These dogs have been described as being: Loving of children and family, good alarm barkers, playful, "pugnacious", independently minded, stable, liking lots of human companionship.
Considered good for rural or urban environments, they have low grooming needs and may snore. They enjoy children and other pets, tend to obesity, have low exercise needs but some activity is needed to help them keep a proper body weight. They don't tolerate hot weather. They have low grooming needs; just a quick daily brush will do, and hygiene is needed around facial folds especially at eyes.

Normal Physiologic Variations
A UK study showed 27.4% of litters were born via Cesarean section.
Drug Sensitivities
None reported

Inherited Diseases
Hip Dysplasia and Legg-Perthes Disease: Polygenically inherited traits causing degenerative joint disease and hip arthritis. Reported 65.6x odds ratio for Legg-Calve-Perthes versus other breeds. OFA reports 64.1% affected.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. Reported 3.3x odds ratio versus other breeds. OFA reports 61.4% affected.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. OFA reports 7.3% affected.

Disease Predispositions
Brachycephalic Complex: Can cause dyspnea, and collapse. Includes Elongated Soft Palate, Stenotic Nares, Hypoplastic Trachea, and Everted Laryngeal Saccules. Clinical signs are associated with bronchial collapse. Nasopharyngeal turbinates may also play a role. Surgery is indicated in severe cases. Identified in 26.0% of Pugs in an Australian study. Dorn reports a 13.3x odds ratio in Pugs versus other breeds.
Entropion: A rolling in of the eyelids that can cause corneal irritation and ulceration. Dorn reports a 2.94x odds ratio in Pugs versus other breeds. Entropion is reported in 21.00% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005.
Exposure Keratopathy Syndrome/Pigmentary Keratitis: Corneal reactivity and drying from ocular exposure secondary to shallow orbits, exophthalmos, and lagophthalmos. Identified in 16.55% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005.
Persistent Pupillary Membranes: Strands of fetal remnant connecting; iris to iris, cornea, lens, or involving sheets of tissue. The later three forms can impair vision, and dogs affected with these forms should not be bred. Identified in 9.87% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005.
Distichiasis: Abnormally placed eyelashes that irritate the cornea and conjunctiva. Can cause secondary corneal ulceration. Identified in 8.62% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005.
Hypothyroidism: Inherited autoimmune thyroiditis. 5.6% positive for thyroid autoantibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Allergic Dermatitis (Atopy): Inhalant or food allergy. Presents with pruritis and pyotraumatic dermatitis (hot spots). Pugs have a significantly increased risk for atopy versus other breeds.
Chronic Superficial Keratitis (Pannus): Chronic corneal inflammatory process that can cause vision problems due to corneal pigmentation. Treatment with topical ocular lubricants and anti-inflammatory medication. Identified in 3.20% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Pug with the condition.
Macroblepharon: Abnormally large eyelid opening; may lead to secondary conditions associated with corneal exposure. Identified in 3.06% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005.
Mast Cell Tumor (MCT): Histamine producing skin tumors that produce inflammation and ulceration. Can metastasize or reoccur locally following surgical removal. Pugs have a 4 to 8 times greater risk for developing cutaneous mast cell tumors than other breeds. Cataracts: Anterior, posterior, intermediate and punctate cataracts occur in the breed. Unknown mode of inheritance. Reported in 2.28% of Pugs presented to veterinary teaching hospitals. Identified in 1.53% of Pugs CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Pug with a cataract.
Portosystemic Shunt (PSS, Liver Shunt): Abnormal blood vessels connecting the systemic and portal blood flow. Vessels can be intrahepatic, extrahepatic or microvascular dysplasia. Causes stunting, abnormal behavior and possible seizures. Diagnose with paired fasted and feeding serum bile acid and/or ammonium levels, and abdominal ultrasound. Treatment of PSS includes partial ligation and/or medical and dietary control of symptoms. The Pug is a breed at increased risk of having PSS, with an incidence of 1.3% and an odds ratio of 26.2x versus other breeds. Undetermined mode of inheritance.
Pug Dog Encephalitis (PDE): A sporadic, necrotizing meningoencephalitis affecting adolescent and mature pug dogs. Acute and chronic forms occur, with a median age of 19 months, and mean survival of 23 days. Presents with clinical signs of depression, ataxia, or generalized seizures. Anticonvulsants are helpful to control seizures. MRI along with clinical history can be diagnostic. Undetermined mode of inheritance, with a high heritability. Estimated frequency of 1.25% in the breed. Associated with a specific DLA Type II haplotype, especially in the heterozygous state (12.75x Odds Ratio: 75% of affected Pugs have this haplotype) A genetic test for the susceptibility haplotype is available.
Bladder Stones: The Pug is a breed predisposed to develop bladder stones. Stone composition is not identified.
Diabetes Mellitus: Sugar diabetes caused by a lack of insulin production by the pancreas. Controlled by insulin injections, diet, and glucose monitoring. Identified as a breed at increased risk of developing diabetes, with an odds ratio of 3.87x versus other breeds.
Hemivertebra and Butterfly Vertebra: Malformed veterbra can cause scoliosis, pain or spinal cord compression if severe. Can produce Spina Bifida or Sacrocaudal Dysgenesis. Associated with selection for the screw tail. Seen at an increased frequency in the breed. Undetermined mode of inheritance.
Pigmented Plaques: Pugs are predisposed to the development of deeply pigmented, slightly elevated hyperkeratotic noncancerous plaques on the abdomen and limbs. A novel papilloma virus (CPV4) has been isolated from these plaques.
Lung Lobe Torsion: Pugs have a predisposition for spontaneous lung lobe torsion. Median age of 1.5 years, with a male prevalence. Histories included increased weakness, increased respiratory effort, tachypnea, acute collapse, lethargy, anorexia, and cyanosis. Surgical correction is curative, though one reported case had another lobe torsion 2 years later.
Hydrops Fetalis: A previously unreported syndrome of transient mid-gestational hydrops fetalis identified by ultrasound was diagnosed in 16 litters of 16 different Pugs. There was 7.4% fetal resorption, 8.4% abortion, 8.0% stillbirths, 15% neonatal mortality, and 9.6% congenital abnormalities. Pugs were significantly (22.8 times) more likely to be affected than other breeds.
Degenerative Myelopathy (DM): Affected dogs show an insidious onset of upper motor neuron (UMN) paraparesis. The disease eventually progresses to severe tetraparesis. Affected dogs have normal results on myelography, MRI, and CSF analysis. Necropsy confirms the condition. Unknown mode of inheritance. A direct genetic test for an autosomal recessive DM susceptibility gene is available. All affected dogs are homozygous for the gene, however only a small percentage of homozygous dogs develop DM. OFA reports DM susceptibility gene frequencies of 29% carrier, and 2% homozygous "at-risk".
Brachygnathism, Cleft Palate, Cryptorchidism, Demodicosis, Fold Dermatitis, Lentigo, Oligodontia, and Progressive Retinal Atrophy are reported.

Isolated Case Studies
Second Degree Heart Block: A colony of Pugs was established with intermittent sinus pauses and paroxysmal second degree heart block. Pathological findings included stenosis of the midportion of the His bundle, which appears to be a heritable trait in these purebred Pug dogs.
Pigmented Cutaneous Papillomatosis (Pigmented Epidermal Nevus): Three cases of pigmented cutaneous papillomatosis (previously described also as CPEN) in pug dogs were investigated histopathologically, immunohistochemically and electron microscopically. PCR amplification targeted for the L1 gene of papillomavirus cloned from a case of CPEN yielded an expected fragment of 194-bp in the two CPEN cases examined but not in a case of canine oral papilloma.33 XX-Sex Reversal: A case of a male appearing Pug with Sry-negative XX-sex reversal was identified in Italy. The dog had a prepuce and an enlarged clitoris. A uterus was present. The gonads had seminiferous tubules lined by Sertoli cells.
Double-Chambered Right Ventricle: A 32-month-old spayed female Pug was identified with a ventricular septal defect and double chambered right ventricle by echocardiography and pathological examinations. An anomalous muscle bundle crossed the right ventricular outflow tract, dividing the right ventricle into 2 chambers. There were no clinical abnormalities found.

Genetic Tests
Tests of Genotype: A direct susceptibility test for PDE is available frm UC-Davis VGL.
A direct test for a DM susceptibility gene is available from OFA. Direct test for black and fawn coat color is available from HealthGene and VetGen.
Tests of Phenotype: CHIC Certification: Hip radiographs, patella evaluation, CERF eye examination (every 3 years), and genetic test for PDE. (See CHIC website; caninehealthinfo.com). Recommend elbow radiographs, thyroid profile including autoantibodies, and cardiac examination.

Miscellaneous
- Breed name synonyms: Mops (Germany), Mopshond (Dutch for Grumbler), Carlin (France), Dutch Pug, Lo-Sze (Chinese word for ancient pug)
- Registries: AKC, UKC, CKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club)
- AKC rank (year 2008): 15 (12,202 dogs registered)
- Internet resources: Pug Dog Club of America: pugs.org
Pug Club of Canada: pugcanada.com
The Pug Dog Club (UK): pugdogclub.org.uk