Malamute Research Articles

FACTOR VII DEFICIENCY IN POLISH HOUND – ACCIDENTAL EVENT OR NEW PERMANENT RISK?

The Polish Hound (ogar polski) is a small, old breed of hunting dogs.The breed was recognized by the Fédération Cynologique Internationale (FCI) in 1966.A three–year–old Polish Hound male, was admitted to the Clinic of Internal Diseases of Companion Animals of Life Science University in Lublin because of signs of haemorhagic diathesis. There was no preceding history of trauma. General clinical examination was unremarkable. On initial diagnostic testing prothrombin time (PT)of the patient was prolonged nearly by three times. To characterize the dog’s coagulopathy further, samples were collected for coagulation screening tests, mixing studies and factor analyses. Investigations revealed factor VII activity below 2%.Unfortunately we had been unable to determine whether the disorder is inherited or is the result of a spontaneous mutation. It is very likely that the nature of described deficit is inherited. Canine hereditary FVII deficiency was first described in 1962 as an incidental finding in Beagles. Later, the defect was identified in another breeds, such as: English Bulldogs, Alaskan Malamutes, Miniature Schnauzers, Boxers, Scottish Deerhounds, Alaskan Klee Kai Dog and mixed–breed dogs. In 2005 a molecular characterization of FVII deficiency in Beagles was described. Unfortunately we had been unable to determine whether the disorder is inherited or is the result of a spontaneous mutation. To our knowledge this case is the first to report of isolated factor VII deficiency in Polish Hound.

Ethmoidal Meningoencephalocele Associated with Seizure in a Juvenile Alaskan Malamute

Signalment: An 8-month-old female Alaskan malamute was presented for progressive cluster seizure disorder. Results: There were no abnormalities on neurological examination, survey radiographs, or blood analysis. Magnetic resonance (MR) imaging and computed tomography revealed extension of the olfactory bulb and frontal lobe into the nasal cavity. They also confirmed abnormal anatomy of the nasal turbinates within the rostral part of the nasal cavity and the absence of a cribriform plate. On T2-weighted and fluid-attenuated inversion recovery images, the herniated brain showed heterogeneous and hyperintense signals consistent with intraparenchymal edema. Transverse MR images showed brain herniation into the right frontal cavity and an asymmetrical lateral ventricle because of a left midline shift. On contrast-enhanced MR images, the protruding brain parenchyma was mildly enhanced. Ethmoidal encephalocele was suspected as the final diagnosis. Despite symptomatic treatment, the dog continued to exhibit seizures and was euthanized. Clinical relevance: Ethmoidal encephalocele is a rare disease in dogs. However, it could be considered as a cause of seizure in young dogs.

Breed-specific reference intervals for assessing thyroid function in seven dog breeds.

Thyroxine (T4), free T4 (FT4), and thyrotropin (TSH) concentrations were measured in serum from 693 healthy representatives from 7 dog breeds (Alaskan Malamute, Collie, English Setter, Golden Retriever, Keeshond, Samoyed, or Siberian Husky) to determine whether breed-specific reference intervals (RIs) are warranted. Veterinarians reviewed the health history, performed a physical examination, and approved laboratory data for the enrolled dogs. Many purebred dogs had T4 and FT4 concentrations that were at, or below, the lower limits previously determined for non-breed-specific RIs. Mean concentrations of T4, FT4, and TSH varied significantly among breeds. The range of mean concentration of T4 (19.7 nmol/L [1.53 µg/dL] in English Setters to 29.0 nmol/L [2.25 µg/dL] in Keeshonds) and FT4 (12.6 pmol/L [0.98 ng/dL] in English Setters to 20.2 pmol/L [1.57 ng/dL] in Samoyeds) was considerable. Median TSH values ranged from 6.10 mIU/L (0.07 ng/mL; Alaskan Malamute and Golden Retriever) to 17.6 mIU/L (0.26 ng/mL; Collie). Mean T4 and FT4 concentrations were higher in females. Increasing age was associated with decreasing T4 and FT4, and increasing TSH concentration. The substantial ranges across breeds of measures of central tendency (mean, median) for all hormones indicate that breed-specific RIs are warranted. RIs encompassing the central 95% of reference values for all breeds combined, and for individual breeds, were calculated using nonparametric (TSH) and robust (T4, FT4) methods. Use of breed-specific RIs in combination with careful attention to the potential for pre-analytical and analytical variability in test results will improve thyroid function assessment in these breeds.

Using multiple markers to elucidate the ancient, historical and modern relationships among North American Arctic dog breeds.

Throughout most of the Americas, post-colonial dogs largely erased the genetic signatures of pre-historical dogs. However, the North American Arctic harbors dogs that are potentially descended from pre-historical ancestors, as well as those affected by post-colonial translocations and admixtures. In particular, Inuit dogs from Canada and Greenland are thought to descend from dogs associated with Thule peoples, who relied on them for transportation ca. 1000 years ago. Whether Thule dogs reflected an earlier colonization by Paleoeskimo dogs ca. 4500 years ago is unknown. During the Alaskan Gold Rush, additional sled dogs, possibly of post-colonial derivation, the Alaskan Husky, Malamute and Siberian Husky, were used in the Arctic. The genealogical relationships among and origins of these breeds are unknown. Here we use autosomal, paternal and maternal DNA markers to (1) test the hypothesis that Inuit dogs have retained their indigenous ancestry, (2) characterize their relationship to one another and to other Arctic breeds, and (3) estimate the age of North American indigenous matrilines and patrilines. On the basis of the agreement of all three markers we determined that Inuit dogs have maintained their indigenous nature, and that they likely derive from Thule dogs. In addition, we provide support for previous research that the Inuit dogs from Canada and Greenland dog should not be distinguished as two breeds. The Alaskan Husky displayed evidence of European introgression, in contrast to the Malamute and Siberian Husky, which appear to have maintained most of their ancient Siberian ancestry.

Determination of 210Po in hair of domestic animals from Poland and Norway

The aim of this study was to investigate the usefulness of hair to monitor the body content level of polonium activity, the utility of animals hair as a non-invasive indicator of exposure for natural 210Po. Among Polish dogs the highest 210Po concentrations were measured in 2 years old Shih Tzu and Bichon Maltese, small longhair males. Among Norwegian, 210Po concentrations were much higher and its highest values were measured in hair collected from 1 year old Greenland Dog and 3 years old Alaskan Malamute, also males. Mainly dogs’ gender and diet influenced the values of 210Po concentrations in analyzed samples.

Histiocytic typhlocolitis in two colony Beagle dogs

Two young female Beagle dogs in a laboratory colony with clinical signs of loose stools and fecal blood were confirmed to have histiocytic ulcerative colitis by histologic evaluation. This syndrome is well recognized in other dog breeds such as Boxers and related French Bulldogs, Mastiffs, Alaskan malamutes and Doberman Pinschers. Formalin-fixed paraffin sections of large intestine from one dog demonstrated the presence of Escherichia coli strain LF82 by immunohistochemistry and 16S ribosomal RNA gene sequencing. E coli strain LF82 has been implicated in the pathogenesis of Crohn's disease and similar bacteria have been cultured from cases of histiocytic ulcerative colitis in Boxer dogs. Spontaneous histiocytic ulcerative colitis must be differentiated from test article-related findings in nonclinical toxicity studies in Beagle dogs.

Discal Cyst in a Malamute Dog

7-year-old, male Alaskan malamute was referred for a routine dental management. On the physical examination, the right hindlimb ataxia with a mild delay in proprioception was noted. On magnetic resonance images, an extradural ventral cystic structure compressing the spinal cord was found at the level between the first and second lumbar vertebra. The cyst showed hypointense on a T1-weighted image with rim enhancement and hyperintense on a T2-weighted image. The cystic lesion was removed through right-side hemilaminectomy. In the histopathological examination, evenly distributed fibroblasts and collagenous stroma with several cartilaginous materials were seen. The neurological signs of the right hindlimb were successfully recovered within a week in follow-up neurological examination and showed normal gait at 6 months after surgery.

Imaging Features of Solitary Spinal Plasmacytoma in a Dog

A 12-year-old, intact, female Alaskan malamute presented with severe spinal pain and hind limb lameness. On radiographs, a round, demarcated lytic lesion was identified in the central fifth lumbar vertebra. On magnetic resonance imaging (MRI), the lesion involving the spinal cord appeared hypointense on T1 weighted, hyperintense on T2 weighted, heterogeneously enhanced on post-contrast T1 weighted, and hypointense on GE images. A focal, small, ill-defined, lytic lesion was also observed radiographically in the sixth lumbar vertebra, it appeared as a focal hyperintense lesion on T1 weighted, T2 weighted, and GE images and showed focal enhancement on post-contrast T1 weighted images. She was euthanized owing to extreme pain and severe and progressive clinical signs; a plasmacytoma was histopthologically diagnosed. This report presents an unusual type of spinal tumor, plasmacytoma. MRI is a useful modality to evaluate the anatomic location and extension of spinal lesions.

Prevalence of lumbosacral transitional vertebrae in dogs in the Czech Republic

Lumbosacral transitional vertebra is a common congenital anomaly of the spine in dogs. It is a predisposing factor for degeneration of the lumbosacral spine and development of cauda equina syndrome or hip dysplasia in affected dogs. The aim of the study was to determine breed predisposition, types, and prevalence of lumbosacral transitional vertebrae in the canine population in the Czech Republic. The value of laterolateral radiographs of the lumbosacral junction in the diagnosis of LTV was also evaluated. Prevalence of lumbosacral transitional vertebrae was determined by reviewing ventrodorsal radiographs of pelvis with an extended hip of 1,878 dogs. Lumbosacral transitional vertebrae were detected in 188 dogs (10%). German Shepherd, Alaskan Malamute and Bohemian Shepherd were found to be highly predisposed breeds. The most common type of lumbosacral transitional vertebra was type II with separation of the first sacral vertebra from sacrum and presence of rudimentary intervertebral space between S1 and the sacral median crest (37.8% of the lumbosacral transitional vertebrae). Type I was detected in 29.2% and the asymmetric type of the lumbosacral transitional vertebra (type III) in 33%. Laterolateral radiograph of the lumbosacral spine was evaluated in 126 dogs from 188 with lumbosacral transitional vertebrae. Rudimentary intervertebral disc space between S1 and S2 in laterolateral radiographs was detected in 100% of lumbosacral transitional vertebrae with type II and III, and was not detected in type I. The findings on lumbosacral transitional vertebrae in the Czech Republic will extend knowledge about the disease. Both ventrodorsal hip-extended and laterolateral radiographs should be recommended for routine screening and reliable differentiation among the three different types of lumbosacral transitional vertebra.

Pre-Columbian origins of Native American dog breeds, with only limited replacement by European dogs, confirmed by mtDNA analysis

Dogs were present in pre-Columbian America, presumably brought by early human migrants from Asia. Studies of free-ranging village/street dogs have indicated almost total replacement of these original dogs by European dogs, but the extent to which Arctic, North and South American breeds are descendants of the original population remains to be assessed. Using a comprehensive phylogeographic analysis, we traced the origin of the mitochondrial DNA lineages for Inuit, Eskimo and Greenland dogs, Alaskan Malamute, Chihuahua, xoloitzcuintli and perro sín pelo del Peru, by comparing to extensive samples of East Asian (n = 984) and European dogs (n = 639), and previously published pre-Columbian sequences. Evidence for a pre-Columbian origin was found for all these breeds, except Alaskan Malamute for which results were ambigous. No European influence was indicated for the Arctic breeds Inuit, Eskimo and Greenland dog, and North/South American breeds had at most 30% European female lineages, suggesting marginal replacement by European dogs. Genetic continuity through time was shown by the sharing of a unique haplotype between the Mexican breed Chihuahua and ancient Mexican samples. We also analysed free-ranging dogs, confirming limited pre-Columbian ancestry overall, but also identifying pockets of remaining populations with high proportion of indigenous ancestry, and we provide the first DNA-based evidence that the Carolina dog, a free-ranging population in the USA, may have an ancient Asian origin.

Retroperitoneal epidermoid cyst in a dog

Epidermoid cysts (EC) are benign lesions of ectodermal origin lined by a stratified squamous epithelium that resembles normal epidermis, but lacks the skin appendage present in dermoid cysts (Hagr and...

Genomic deletion of CNGB3 is identical by descent in multiple canine breeds and causes achromatopsia

BackgroundAchromatopsia is an autosomal recessive disease characterized by the loss of cone photoreceptor function that results in day-blindness, total colorblindness, and decreased central visual acuity. The most common causes for the disease are mutations in the CNGB3 gene, coding for the beta subunit of the cyclic nucleotide-gated channels in cones. CNGB3-achromatopsia, or cone degeneration (cd), is also known to occur in two canine breeds, the Alaskan malamute (AM) and the German shorthaired pointer.ResultsHere we report an in-depth characterization of the achromatopsia phenotype in a new canine breed, the miniature Australian shepherd (MAS). Genotyping revealed that the dog was homozygous for a complete genomic deletion of the CNGB3 gene, as has been previously observed in the AM. Identical breakpoints on chromosome 29 were identified in both the affected AM and MAS with a resulting deletion of 404,820 bp. Pooled DNA samples of unrelated purebred Australian shepherd, MAS, Siberian husky, Samoyed and Alaskan sled dogs were screened for the presence of the affected allele; one Siberian husky and three Alaskan sled dogs were identified as carriers. The affected chromosomes from the AM, MAS, and Siberian husky were genotyped for 147 SNPs in a 3.93 Mb interval within the cd locus. An identical shared affected haplotype, 0.5 Mb long, was observed in all three breeds and defined the minimal linkage disequilibrium (LD) across breeds. This supports the idea that the mutated allele was identical by descent (IBD).ConclusionWe report the occurrence of CNGB3-achromatopsia in a new canine breed, the MAS. The CNGB3-deletion allele previously described in the AM was also observed in a homozygous state in the affected MAS, as well as in a heterozygous carrier state in a Siberian husky and Alaskan sled dogs. All affected alleles were shown to be IBD, strongly suggesting an affected founder effect. Since the MAS is not known to be genetically related to the AM, other breeds may potentially carry the same cd-allele and be affected by achromatopsia.

A Gly98Val Mutation in the N-Myc Downstream Regulated Gene 1 (NDRG1) in Alaskan Malamutes with Polyneuropathy

The first cases of early-onset progressive polyneuropathy appeared in the Alaskan Malamute population in Norway in the late 1970s. Affected dogs were of both sexes and were ambulatory paraparetic, progressing to non-ambulatory tetraparesis. On neurologic examination, affected dogs displayed predominantly laryngeal paresis, decreased postural reactions, decreased spinal reflexes and muscle atrophy. The disease was considered eradicated through breeding programmes but recently new cases have occurred in the Nordic countries and the USA. The N-myc downstream-regulated gene (NDRG1) is implicated in neuropathies with comparable symptoms or clinical signs both in humans and in Greyhound dogs. This gene was therefore considered a candidate gene for the polyneuropathy in Alaskan Malamutes. The coding sequence of the NDRG1 gene derived from one healthy and one affected Alaskan Malamute revealed a non-synonymous G>T mutation in exon 4 in the affected dog that causes a Gly98Val amino acid substitution. This substitution was categorized to be “probably damaging” to the protein function by PolyPhen2 (score: 1.000). Subsequently, 102 Alaskan Malamutes from the Nordic countries and the USA known to be either affected (n = 22), obligate carriers (n = 7) or healthy (n = 73) were genotyped for the SNP using TaqMan. All affected dogs had the T/T genotype, the obligate carriers had the G/T genotype and the healthy dogs had the G/G genotype except for 13 who had the G/T genotype. A protein alignment showed that residue 98 is conserved in mammals and also that the entire NDRG1 protein is highly conserved (94.7%) in mammals. We conclude that the G>T substitution is most likely the mutation that causes polyneuropathy in Alaskan Malamutes. Our characterization of a novel candidate causative mutation for polyneuropathy offers a new canine model that can provide further insight into pathobiology and therapy of human polyneuropathy. Furthermore, selection against this mutation can now be used to eliminate the disease in Alaskan Malamutes.

Subepidermal blistering disease in a 5-month-old Alaskan Malamute dog with concurrent megaesophagus

A 5-month-old, intact male, Alaskan malamute dog was presented with a history of vesiculating, ulcerative and erythematous macules on the face, abdomen, trunk, ear pinnae, perianal region, oral cav...

Ancient DNA evidence for genetic continuity in arctic dogs

The domestic dog fulfills many functions for their human companions, such as hauling, guarding, and protection. Consequently, humans have taken dogs to nearly every corner of the globe. Recent translocations of Western dogs stemming from the Victorian era dog fancy have erased some of the ancient genetic signatures of these earlier migrations. Here we used DNA of ancient and modern dogs from the North American Arctic of Alaska and Greenland to assess their genetic continuity in time and space. We successfully sequenced 23 archaeological (ca. AD 1250–1910) and recent (ca. AD 1930–1990) surface-collected Canis bone and tooth samples and compared them to 51 modern Inuit Sled Dogs and to published sequences of modern Alaskan Malamutes (and additional Inuit Sled Dogs) to test for evidence of lineage replacement or genetic continuity through time. Ancient samples from Alaska and Greenland and modern sequences from Greenland all contained a high frequency of haplotype A31, which was previously described only in modern North American Arctic dogs. Thus, A31 was a common thread tying the entire North American Arctic together prior to European colonization and, in the Eastern Arctic, indicates genetic continuity between past and present dogs as well. However, A31 is rare in modern Alaskan dogs, consistent with post-colonization replacement by Eurasian matrilines.

Hereditary polyneuropathy in the Alaskan Malamute

To prove the hypothesis that a polyneuropathy in Alaskan Malamutes has a genetic background. Pedigrees of 131 related Alaskan Malamutes were included in the current study. Neurological examination, electrodiagnosis as well as muscle and nerve biopsies could be performed in 10 dogs. Information about the disease status of the other 121 Alaskan Malamutes were supplied by referring veterinarians, breeders and owners. Segregation analysis using four different models (monogenic, polygenic, mixed monogenic-polygenic and the phenotypic model) was performed on 71 dogs to test the different mechanisms of genetic transmission. In seven clinically affected dogs abnormal electromyographic findings and reduced nerve conduction velocity were detected. Suspected diagnosis of polyneuropathy was confirmed by nerve biopsy results, characterized by axonal degeneration and hypomyelination. Muscle specimens revealed signs of neurogenic myopathy. Three related clinically normal Alaskan Malamutes also displayed moderate neuromuscular changes in histopathology. In the segregation analysis the polygenic model proved as best suitable to explain the observed segregation pattern among all other models tested. The current study could demonstrate that polyneuropathy in Alaskan Malamutes is a hereditary disease with variable phenotypic expression ranging from severely affected to subclinical forms, which has to be considered in future gene analysis studies.

Osteosarcoma at the site of titanium orthopaedic implants in a dog

An Alaskan Malamute underwent unilateral tibial tuberosity advancement (TTA) surgery to stabilise a stifle joint with a deficient cranial cruciate ligament. The dog made an excellent recovery with no postoperative complications, until 20 months post-surgery when he presented with acute onset ipsilateral pelvic limb lameness. Osteosarcoma (OSA) was diagnosed adjacent to the titanium implants. Currently, there is a paucity of information on the epidemiology of OSA adjacent to orthopaedic implants in canine patients. The clinical, radiological and pathological findings of this case of periprosthetic OSA, and a potential causal relationship between titanium implants and bone neoplasia, are discussed.

Breed-specific ancestry studies and genome-wide association analysis highlight an association between the MYH9 gene and heat tolerance in Alaskan sprint racing sled dogs

Alaskan sled dogs are a genetically distinct population shaped by generations of selective interbreeding with purebred dogs to create a group of high-performance athletes. As a result of selective breeding strategies, sled dogs present a unique opportunity to employ admixture-mapping techniques to investigate how breed composition and trait selection impact genomic structure. We used admixture mapping to investigate genetic ancestry across the genomes of two classes of sled dogs, sprint and long-distance racers, and combined that with genome-wide association studies (GWAS) to identify regions that correlate with performance-enhancing traits. The sled dog genome is enhanced by differential contributions from four non-admixed breeds (Alaskan Malamute, Siberian Husky, German Shorthaired Pointer, and Borzoi). A principal components analysis (PCA) of 115,000 genome-wide SNPs clearly resolved the sprint and distance populations as distinct genetic groups, with longer blocks of linkage disequilibrium (LD) observed in the distance versus sprint dogs (7.5-10 and 2.5-3.75kb, respectively). Furthermore, we identified eight regions with the genomic signal from either a selective sweep or an association analysis, corroborated by an excess of ancestry when comparing sprint and distance dogs. A comparison of elite and poor-performing sled dogs identified a single region significantly associated with heat tolerance. Within the region we identified seven SNPs within the myosin heavy chain 9 gene (MYH9) that were significantly associated with heat tolerance in sprint dogs, two of which correspond to conserved promoter and enhancer regions in the human ortholog.

Dystrophin-deficient muscular dystrophy in an Alaskan malamute

DYSTROPHIN-deficient muscular dystrophy is an X-linked inherited degenerative myopathy. It is the most common form of muscular dystrophy seen in dogs, and is similar to that termed Duchenne's muscular dystrophy...

The Curious Case of Dingoes

Among all Australian mammals, or for that matter,mammals as a whole, the case for the dingoes has been acurious one. Having arrived in Australia only about4–5,000 years ago, the dingoes are not native to theAustralian fauna, which is dominated by marsupials thathave existed in isolation there for millions of years, and itdid not arrive with the first humans who reached Australiaabout 50,000 years ago (dogs may not have beendomesticated at that time). However, whatever the circum-stances that brought the dingoes to the Australian continent(either with the aid of seafaring Polynesians or by islandhopping), dingoes have become a top predator, and as aplacental mammal, their impact on the native marsupialfaunas is disproportionally large. There are also the unendingcontroversies over the status of the dingo as a pest to becontrolled or as a keystone hypercarnivore that plays a vitalrole in the ecology of the entire continent. Even the name“dingo” could not be traced to any Australian aboriginallanguages, and may be a construct of European colonialsettlers. Thus, aggregated in a single animal is an interestingmixture of unique historic circumstances, placental-marsupialinteractions, as well as the more volatile human prejudicesover its impact on livestock and wildlife.In a continent full of “naive” marsupials, the arrival of alarge placental predator, such as the Australian aboriginesduring the late Pleistocene, can have devastating effects onthe native megafaunas, as shown in recent studies in TightEntrance Cave of southwestern Australia (Prideaux et al.2010). Although few archaeological records exist todocument a similar impact of the dingoes before the arrivalof the Europeans, it is safe to assume that dingoes musthave played important roles in shaping modern marsupialcommunities. Whatever that impact might have been,dingoes are now well integrated in the Australian mammalcommunity and play a major role at the top of the foodchain.Readers of this journal naturally want to know, what isthe dingo? To whom is it related among extant canids? Is ita wolf or a domestic dog? If the former, how do wedistinguish dogs from dingoes? Unfortunately, Purcell’seffort to summarize current research is inaccurate, possiblybiased by the conservation point of view. Data related to thegenealogical relationships of dingoes were largely morpho-logical in traditional studies, but increasingly molecularevidence (mitochondrial and nuclear DNA) is taking over,because of the explosive growth of sequencing technologiesin recent years and because of its far larger dataset withgreater power in resolving phylogenies. This is especiallytrue where extant representatives (the various subspecies ofgray wolves and dog breeds) make up a dense sample of thephylogeny. The latest and most authoritative genome-wide,single nucleotide polymorphisms study (with 48,000 SNPs)suggests that dingoes, along with New Guinea singing dog,represent an ancient breed of dogs that fall in a small cladeincluding the Alaskan malamute, Siberian husky, ChineseShar Pei, Akita, and chow chow (vonHoldt et al. 2010).Curiously, Purcell (p. 30), commenting on vonHoldt et al.(2010), concluded that dingoes are “one of the closestliving relatives of the gray wolf … and most likely the lastform of primitive canid before the domestication of thedog.” Purcell’s statements in this regard are inconsistentwith vonHoldt et al.’s(2010) phylogeny.It is understandable that conservationists may prefer toregard the dingoes as a subspecies of the gray wolf (Canis