Dogs In Australia Research Articles

Fluoroquinolone-resistant extraintestinal Escherichia coli clinical isolates representing the O15:K52:H1 clonal group from humans and dogs in Australia

Antimicrobial-resistant extraintestinal pathogenic Escherichia coli (ExPEC) impact both human and veterinary medicine. One ExPEC clonal group that has become increasingly multidrug-resistant is serotype O15:K52:H1. Accordingly, we sought O15:K52:H1 strains among fluoroquinolone-resistant (FQ(r)) E. coli clinical isolates from humans (n=582) and dogs (n=120) in Australia. The phylogenetic group D isolates (267/702; 38%) were screened for O15:K52:H1-specific single-nucleotide polymorphisms (SNPs) in fumC and the O15 rfb variant. The 34 so-identified O15:K52:H1 isolates (33 human, 1 canine) underwent antimicrobial susceptibility profiling, virulence genotyping, and macrorestriction profiling. Although susceptibility profiles varied, the 34 isolates were closely related by pulsed-field gel electrophoresis and exhibited typical O15:K52:H1-associated virulence profiles (complete pap operon, F16 papA allele, papG allele II, iha, fimH, sat, fyuA, iutA, kpsMII, ompT). The canine isolate closely resembled human isolates. Thus, O15:K52:H1 strains contribute to the FQ(r) ExPEC population in Australia and may potentially be transferred between humans and dogs.

Seven considerations about dingoes as biodiversity engineers: the socioecological niches of dogs in Australia

Australian dingoes have recently been suggested as a tool to aid biodiversity conservation through the reversal or prevention of trophic cascades and mesopredator release. However, at least seven ecological and sociological considerations must be addressed before dog populations are positively managed.Domestication and feralisation of dingoes have resulted in behavioural changes that continue to expose a broad range of native and introduced fauna to predation.Dingoes and other dogs are classic mesopredators, while humans are the apex predator and primary ecosystem engineers in Australia.Anthropogenic landscape changes could prevent modern dingoes from fulfilling their pre-European roles.Dingoes are known to exploit many of the same species they are often presumed to ‘protect’, predisposing them to present direct risks to many threatened species.The assertion that contemporary dog control facilitates the release of mesopredators disregards the realities of effective dog control, which simultaneously reduces fox and dog abundance and is unlikely to enable increases in fox abundance.The processes affecting threatened fauna are likely a combination of both top-down and bottom-up effects, which will not be solved or reversed by concentrating efforts on managing only predator effects.Most importantly, human social and economic niches are highly variable across the ecosystems where dingoes are present or proposed. Human perceptions will ultimately determine acceptance of positive dingo management.Outside of an adaptive management framework, positively managing dingoes while ignoring these seven considerations is unlikely to succeed in conserving native faunal biodiversity but is likely to have negative effects on ecological, social and economic values.

Oocysts and high seroprevalence of Neospora caninum in dogs living in remote Aboriginal communities and wild dogs in Australia

Canines are definitive hosts of Neospora caninum (Apicomplexa). For horizontal transmission from canines to occur, viable oocysts of N. caninum must occur in the environment of susceptible intermediate hosts. Canids in Australia include wild dogs and Aboriginal community dogs. Wild dogs are those dogs that are not dependent on humans for survival and consist of the dingo, feral domestic dog and their hybrid genotypes. Aboriginal community dogs are dependent on humans, domesticated and owned by a family, but are free-roaming and have free access throughout the community. In this study the extent of N. caninum infection was determined in a total of 374 dogs (75 wild dogs and 299 Aboriginal community dogs) using a combination of microscopic, molecular and serological techniques. Oocysts of N. caninum were observed in the faeces of two juvenile Aboriginal community dogs (2/132; 1.5%). To estimate N. caninum prevalence, a new optimised cut-off of 18.5% inhibition for a commercial competitive ELISA was calculated using a two-graph receiver-operating characteristic (TG-ROC) analysis and IFAT as the gold standard resulting in equal sensitivity and specificity of 67.8%. Of the 263 dog sera tested the true prevalence of N. caninum antibodies was 27.0% (95% confidence limit: 10.3–44.1%). The association between the competitive ELISA results in dogs less than 12 month old and older dogs was significant (P=0.042). To our knowledge this is the first large scale parasitological survey of the Aboriginal community dogs and wild dogs from Australia. The high prevalence of N. caninum infection in Aboriginal community dogs illustrates that horizontal transmission of N. caninum is occurring in Australia. These results demonstrated that N. caninum in dogs is widespread, including the semi-arid to arid regions of north-western New South Wales and the Northern Territory. The populations of free-ranging dogs are likely to be important contributors to the sylvatic life cycle of N. caninum.

Symmetry of hip dysplasia traits in the German Shepherd Dog in Australia

Canine hip dysplasia (CHD) is a common and debilitating developmental condition of the canine coxofemoral (hip) joint, exhibiting a multifactorial pattern of inheritance. British Veterinary Association hip traits (BVAHTs) are nine radiographic features of hips used in several countries to ordinally score both the right and left hip of potential breeding candidates to assess their suitability for breeding. The objective of this study was to examine some aspects of the relationship between contralateral scores for each BVAHT in a cohort of 13 124 Australian-registered German Shepherd Dogs. Goodman and Kruskal gamma coefficients of 0.48-0.95 and correlation coefficients of 0.50-0.74 demonstrate that the association between right and left hip scores varies between moderate and strong for BVAHTs. Principal component analysis of scores detected a sizeable left-versus-right effect, a finding supported by symmetry and quasi-symmetry analyses which found that seven of the nine BVAHTs display significant marginal asymmetry. Dogs showing asymmetry for one BVAHT are significantly more likely to display asymmetry at other BVAHTs. When asymmetry is expressed as a binary trait (either symmetrical or asymmetrical), it displays low to moderate heritability. Estimates of genetic correlations between right and left scores are very high for all BVAHTs (>0.945), suggesting right and left scores for each BVAHT are largely determined by the same set of genes. The marginal asymmetries are therefore more likely to be of environmental and non-additive genetic origin. In breeding programmes for CHD, we recommend that scores from both hips be used to estimate breeding values, with a term for side-of-hip included in the model to account for score variation owing to asymmetry.

Experimental infection with Ancylostoma ceylanicum in dogs and efficacy of a spot on combination containing imidacloprid 10% and moxidectin 2.5% (Advocate ® /Advantage ® Multi, Bayer Animal Health)

Ancylostoma ceylanicum is a common hookworm of dogs, cats and humans in Asia. More recently, this hookworm was found to infect dogs in Australia. The objective of this study was to determine the efficacy of a spot on combination product containing imidacloprid 10% and moxidectin 2.5% (Advocate/Advantage Multi, Bayer Animal Health) against A. ceylanicum in experimentally infected dogs. Twelve dogs were each subcutaneously injected with 300 infective third-stage larvae of A. ceylanicum. Pups were stratified by egg count and randomly allocated equally into control and treatment groups. The pups in the treatment group were each treated with a spot on combination of 10% (w/v) imidacloprid and 2.5% (w/v) moxidectin, administered topically at the skin surface between the shoulder blades. The dogs in the control group were not treated. Egg counts were performed daily until the end of the study period and compared for the treated and control groups. No eggs were detected in the treated group of pups within 4 days of treatment and faecal samples from this group remained negative throughout the rest of the study, resulting in a treatment efficacy (egg reduction) of 100% (P < 0.0001). The egg counts remained high (4,469 +/- 2,064 eggs per gram, epg) in the untreated control group for the rest of the study period. This study demonstrated that the spot on combination containing imidacloprid 10% and moxidectin 2.5 % (Advocate/Advantage Multi, Bayer Animal Health) given at the recommended dose is highly effective against infection with A. ceylanicum in dogs.

Efficacy of a combination product containing pyrantel, febantel and praziquantel (Drontal® Plus Flavour, Bayer Animal Health) against experimental infection with the hookworm Ancylostoma ceylanicum in dogs

Ancylostoma ceylanicum is a common hookworm of dogs, cats and humans in Asia. More recently, this hookworm was found to infect dogs in Australia. The objective of this study was to determine the efficacy of a combination product containing pyrantel, febantel and praziquantel (Drontal) Plus Flavour, Bayer) against A. ceylanicum in experimentally infected dogs. Twelve dogs were each subcutaneously injected with 300 infective third-stage larvae of A. ceylanicum. Pups were stratified by egg count and randomly allocated equally into control and treatment groups. The pups in the treatment group were treated orally at 20 days post-infection with a tablet containing pyrantel, febantel and praziquantel (Drontal Plus Flavour, Bayer) with the recommended dose of one tablet per 10 kg bodyweight. The dogs in the control group were not treated. Egg counts were performed daily until the end of the study period and compared for the treated and control groups. No eggs were detected in the treated group of pups within 3 days of treatment, and faecal samples from this group remained negative throughout the rest of the study resulting in a treatment efficacy (egg reduction) of 100% (p = 0.0011). The egg counts for the untreated group remained high for the rest of the study period. This trial demonstrated that a combination tablet containing pyrantel, febantel and praziquantel (Drontal Plus Flavour, Bayer) given at the manufacturer's recommended dose is effective against infection with A. ceylanicum in dogs.

Isolation of Toxoplasma gondii from the brain of a dog in Australia and its biological and molecular characterization

Toxoplasma gondii was isolated from the brain of a young dog for the first time in Australia. The identity of the parasite was confirmed by PCR, Western blotting, electron microscopy and cat bioassay. Genotyping of the isolate (TgDgAu1) was determined by PCR-RFLP markers that showed it to be a Type II strain. Western blotting demonstrated the presence of IgM antibodies to T. gondii suggesting the bitch was probably infected during pregnancy and the T. gondii was transmitted to the pups congenitally. We believe this represents the first description of a natural case of congenital transmission of T. gondii in the dog.

Evaluation of the thyroid status of Basenji dogs in Australia

To determine the thyroid status of Basenji dogs in Australia. Jugular or cephalic venipuncture blood samples were taken from 113 Basenji, comprising 47 males, 5 castrates, 48 entire and 13 spayed bitches, and sent on ice in plain and EDTA tubes to a single laboratory to determine haematocrit and serum concentrations of total thyroid hormone (thyroxine, TT4), thyroid-stimulating hormone (TSH) and cholesterol. In a subgroup of 8 dogs with abnormal elevated TSH concentrations and subnormal TT4 concentrations, 5 were further examined by dynamic endocrine testing using recombinant human (rh) TSH (54 microg). Ages ranged from 1 to 14 years and weight range was 6.5 to 14.0 kg. TT4 concentrations (nmol/L) ranged from 2 to 27, with a median of 13 and a mean +/- SD of 13.0 +/- 5.7. Importantly, 85/113 (75%) of TT4 values were lower than the normal laboratory reference range (17-37). TSH concentrations (ng/mL) ranged from 0.05 to 5.37, with a median of 0.16 and a mean +/- SD of 0.3 +/- 0.6. Basenji have a similar reference range for serum TSH, but a considerably lower reference range for TT4 (2-27 nmol/L) than most breeds and crossbreds, resembling the sight hounds in this respect. Given the difficulty of accurately measuring TT4 concentrations that are so low, concomitant serial TSH determinations are essential to properly asses thyroid function. Taken alone, TT4 determinations are only of use when the value is within the reference range, in which case a diagnosis of hypothyroidism is likely excluded.

Genetic analysis of canine parvovirus from dogs in Australia

To determine the genetic variants of canine parvovirus-2 (CPV) present in domestic dogs in Australia and to investigate 26 cases of apparent vaccine failure. Thirty-three samples of faeces or intestinal tissues and 16 cell culture virus isolates collected over a period from 1980 to 2005 from five Australian states were analysed. Procedure DNA was extracted from the samples and a 1975 bp fragment of the VP1/2 gene of CPV was amplified by polymerase chain reaction (PCR) and sequenced. Sequences were compared to published strains of CPV-2, CPV-2a, CPV-2b and CPV-2c. Forty-one of 43 PCR-positive samples contained CPV-2a viruses. One sample collected in 2002 from a pup in northern NSW contained a CPV-2b virus. One sample that had been included in the study as a CPV-antigen negative control sample contained a CPV-2 virus. CPV-2a remains the predominant genetic variant of CPV in dogs in Australia and has not been replaced by CPV-2b or CPV-2c as in many other countries. The vaccine failures investigated in the study were likely caused not by genetic variation of field viruses but by maternal antibody interference in the response of pups to vaccination.

Epidemiologic Factors Associated with the Anatomic Location of Intrahepatic Portosystemic Shunts in Dogs

To determine whether breed, sex, country of origin, and age are associated with anatomic location of intrahepatic portosystemic shunts (IHPSS) in dogs. Multi-institutional retrospective case series. Dogs (n=125) with IHPSS from the veterinary teaching hospitals of the University of Florida (21), Sydney University (44), and the University of California-Davis (60). Dogs with surgical/necropsy confirmation of single IHPSS were identified. Data were analyzed using logistic regression for associations between age, breed, sex, and country with the anatomic location of IHPSS. Right (34%), left (34%), and central divisional IHPSS (32%) were prevalent with approximately equal frequency in Australia; in the United States, the prevalence of right (24%) and central divisional (26%) combined was similar to left divisional IHPSS (51%). Country (P=048), sex (P=.016), and Australian cattle dog ([ACD], P=.025) were significantly associated with IHPSS location. Dogs in Australia had 2.5-fold higher odds of having right versus left divisional IHPSS. Males and ACD had 2.8- and 5.6-fold higher odds of having right versus left divisional IHPSS. Australian dogs were significantly older than those in the United States (P<.0001) and ACD were significantly older than other breeds (P=.0067). Although country of origin, breed, and sex had significant associations with anatomic location of IHPSS, signalment does not appear to be a strong predictor of shunt location when used alone. For the common breeds in this report, signalment is only occasionally helpful in predicting likelihood of anatomic division in IHPSS. Australian cattle dogs and male dogs have a statistical association with right (versus left) divisional IHPSS. If advanced imaging techniques are not available, veterinary surgeons should be prepared to locate and address any anatomic configuration of IHPSS in a dog.

A retrospective evaluation of congenital ocular defects in Australian Shepherd dogs in Australia

A retrospective survey of ocular defects in Australian Shepherd dogs was conducted following concerns raised by breeders and owners in Australia. This is the first known such study conducted for this breed. Data from this survey indicate that persistent hyaloid remnants (PHR) were the most common eye defect noted in the Australian Shepherd. Collie eye anomaly (CEA) is the second most common defect noted by veterinary ophthalmologists in the breed in Australia, and extra eyelashes (ectopic cilia/distichia) the third most common. The data also support the hypothesis that PHR may be inherited in this breed. Further investigation is needed to reveal the status of PHR in this breed.

Multifocal Balamuthia mandrillaris infection in a dog in Australia

A 6-year-old male golden retriever, with an 8-month history of seizures and a clinical diagnosis of lymphoma in the central nervous system, was (at the owner's request) euthanized after signs of respiratory distress and shock developed. Upon postmortem examination, the diagnoses of meningoencephalitis and pneumonia were made. A histological examination of selected tissues from both the lung and central nervous system revealed a severe, acute, multifocal, amoebic, embolic pneumonia and a severe, chronic, multifocal, nonsuppurative, amoebic meningoencephalitis. Indirect immunofluorescence analysis confirmed the presence of trophozoite and cyst stages of Balamuthia mandrillaris. This is the first report of B. mandrillaris (which is a free-living amoeba) causing fatal, multifocal granulomatous amoebiasis in a dog in Australia.

Results of surgical correction of abnormalities associated with brachycephalic airway obstruction syndrome in dogs in Australia

To describe clinical features of brachycephalic airway obstructive disease in dogs, the incidence of laryngeal collapse in dogs presenting for surgery and the outcome after surgery in dogs with laryngeal collapse. Basic clinical details were reviewed retrospectively in 73 dogs. Presence of laryngeal collapse and short-term outcomes after surgery were determined for 64 dogs with complete medical records. Long-term outcomes were reviewed for 46 dogs by telephone survey between 19 and 77 months following surgery. Stenotic nares were present in 31 dogs (42.5 per cent), elongated soft palate in 63 (86.3 per cent) and everted laryngeal saccules in 43 (58.9 per cent). The most common breeds were the pug (19 dogs, 26 per cent), Cavalier King Charles spaniel (15 dogs, 20.5 per cent), British bulldog (14 dogs, 19.2 per cent) and Staffordshire bull terrier (4 dogs, 5.5 per cent). Laryngeal collapse was present in 34 of 64 (53 per cent) dogs. No dogs died perioperatively and only one dog was euthanased as a result of its respiratory disease three years after surgery. Telephone interviews indicated that 26 dogs (56.5 per cent) were much improved after surgery, 15 (32.6 per cent) had some improvement and 5 (10.9 per cent) showed no improvement. Signs that persisted after surgery were snoring during sleep (34 dogs, 73.9 per cent), stertor/stridor while conscious (23 dogs, 50 per cent), excessive panting (13 dogs, 28.3 per cent) and dyspnoea (10 dogs, 21.7 per cent). Long-term outcome was considered good, even in dogs with laryngeal collapse. Laryngeal collapse is relatively common in dogs presented for surgical correction of brachycephalic airway obstructive disease. Dogs with severe laryngeal collapse often respond well to surgery. Clinical signs rarely resolve completely following surgery.

Babesia canis vogeli: A novel PCR for its detection in dogs in Australia

Babesia canis vogeli is known to cause disease in dogs in Australia, and the rapid detection of various subspecies would enable effective treatment and management. A 21 bp oligonucleotide, “ Bab- f” was proposed for the production of larger PCR products with high species specificity that would enable effective sequence analyses to yield subspecies identification. The new forward primer when paired with a previously reported “ Babesia common” reverse primer generated a 394 bp product which was successfully amplified and provided subspecies differentiation by sequence analyses. Specificity and sensitivity were reported at 100% on a cohort of 55 dogs.

Molecular detection of Anaplasma platys in lice collected from dogs in Australia

Molecular detection of <i>Anaplasma platys</i> in lice collected from dogs in Australia

Leproid granulomas: a unique mycobacterial infection of dogs

In 1973, a Rhodesian veterinarian, Richard Smith, documented a mycobacterial skin infection in a Doberman and a Rhodesian Ridgeback dog that was characterised by variably sized subcutaneous nodules. It was thought at first that these dogs may have had tuberculosis and, because of public health considerations, they were euthanased and subjected to postmortem examination. There was no internal organ involvement at necropsy and, although acid-fast bacilli (AFB) were abundant in the lesions, culture was negative for the tubercle bacillus. Similar cases were recorded soon thereafter in an Australian veterinary discussion forum, although the infection was not subjected to systematic investigation until the end of the 20th century. The disease was given the name ?canine leprosy? by some veterinary dermatologists, but the alternative name canine leproid granuloma syndrome (CLGS) was later suggested by an Australian veterinarian David Watson. It is now clear that leproid granulomas are not uncommon and indeed are by far the most frequently encountered mycobacterial disease of dogs in Australia.

Systemic antibacterial drug use in dogs in Australia.

A survey of veterinarians' use of antibacterial drugs was conducted by distributing a questionnaire to Australian practitioners. Respondents were asked to indicate their general patterns of use of various systemic antibacterial drugs and drug combinations in dogs and their approach to certain specified clinical disorders. Overall, antibacterials of the beta-lactam type (penicillins and cephalosporins) were most commonly used. Other antibacterials with substantial use were doxycycline, sulphonamide-trimethoprim, metronidazole, fluoroquinolones and clindamycin. Drug selection for different disorders was generally appropriate when compared with recommendations in recent texts, although inappropriate use was evident in some circumstances.

Detection of Ehrlichia platys in dogs in Australia.

To describe the detection of Ehrlichia platys in free-roaming dogs in Central Australia. Blood samples were collected from four dogs and examined for bacterial 16S ribosomal DNA using Polymerase Chain Reaction (PCR)-based assays. The three positive samples obtained were then sequenced and identification of the PCR product carried out. As a result of all three samples being identical to or closely related to part of the 16S rRNA gene of E. platys, blood samples were subsequently obtained from a further 24 dogs. These samples were screened using a PCR-assay to determine the presence of Ehrlichia DNA using genus-specific primers. The positive samples obtained from the screening process were then subjected to a further PCR-assay using E. platys specific primers. Of 28 dogs sampled, Ehrlichia DNA was detected in the blood of 13 dogs. Sequencing of the amplicons obtained indicated a high homology with the 16S rRNA gene for E. platys. When the E. platys-specific PCR was performed for 10 of those dogs, the 678 bp product obtained from the PCR amplification confirmed the identification as part of the 16S rRNA gene of E. platys in all 10 dogs. This study reports for the first time Ehrlichia carriage by dogs in Australia. It also indicates the usefulness of the PCR technique in rapidly and accurately identifying diseases that are otherwise difficult to detect. By using universal primers directed against bacterial 16S ribosomal DNA and sequencing analysis, the detection of potentially pathogenic Ehrlichia organisms that had not previously been found in Australia has been made possible.

Novel lineages of Giardia intestinalis identified by genetic analysis of organisms isolated from dogs in Australia.

Infection of suckling mice with Giardia trophozoites recovered from the intestines of 11 dogs autopsied in Central and Southern Australia in each case produced an established isolate. In contrast, only 1 isolate was obtained by inoculation of faecal cysts. The organisms grew poorly in comparison with isolates from humans or non-canine animal hosts. Light microscopy revealed that the trophozoites had median bodies with the 'claw hammer' appearance typical of G. intestinalis (syn. G. duodenalis, G. lamblia) but that they differed in shape and nuclear morphology from axenic isolates of human or canine origin. Allozymic analysis of electrophoretic data representing 26 loci and phylogenetic analysis of nucleotide sequences obtained from DNA amplified from the glutamate dehydrogenase locus showed that the 11 isolates examined from Australian dogs were genetically distinct from all isolates of G. intestinalis that have been established previously from humans and animals, and also from G. muris. Both analytical methods placed 10 of the Australian canine isolates into a unique genetic lineage (designated Assemblage C) and the eleventh into a deep-rooted second branch (designated Assemblage D), each well separated from the 2 lineages (Assemblages A and B) of G. intestinalis that encompass all the genotypes known to infect humans. In contrast, 4 axenic isolates derived from dogs in Canada and Europe (the only other isolates to have been established from dogs) have genotypes characteristic of genetic Assemblages A or B. The findings indicate that the novel Giardia identified in these rural Australian dogs have a restricted host range, possibly confined to canine species. The poor success rate in establishing Giardia from dogs in vitro suggests, further, that similar genotypes may predominate as canine parasites world-wide. The absence of such organisms among isolates of Giardia that have been established from humans by propagation in suckling mice indicates that they are unlikely to infect humans. However, infection of humans by those dog-derived genotypes that grow in vitro cannot be excluded.

Von Willebrand's disease in Dobermann dogs in Australia

Over a 5-year period (1988-92), von Willebrand factor antigen (vWf:Ag) concentrations were determined on plasma samples from 614 Dobermanns. The vWf:Ag concentration was < 50 canine units (CU)/dL in 373 dogs (61%); these dogs were classified as carriers of the von Willebrand's disease (vWD) gene. In order to identify which dogs were at risk of haemorrhage due to vWD, we determined a cut-off vWf:Ag concentration below which dogs could be considered at risk. This cut-off was chosen in order to minimise the number of dogs genuinely at risk of haemorrhage, being wrongly classified as not at risk. This was done without sacrificing the specificity of the cut-off to any great extent. A vWf:Ag concentration of < 36 CU/dL was empirically chosen as the optimum cut-off concentration. In 282 dogs (76% of the carriers), the vWf:Ag concentration was below this cut-off and these dogs were, thus, classified as being at risk of haemorrhage due to vWD. Haemorrhage attributable to vWD was seen in 107 dogs (29% of the carriers, or 17% of all the dogs). Haemorrhage mostly followed trauma or surgery, but spontaneous genito-urinary and gastrointestinal haemorrhages were also frequent. Of these dogs, 92 were of known age, with a median of 3 years, and 102 were of known sex, with 61% being female. In 89 dogs in which the severity of haemorrhage was subjectively assessed, mild and moderate bleeding occurred with similar frequency (48% and 43%, respectively). There were 8 cases of severe haemorrhage, with two deaths.(ABSTRACT TRUNCATED AT 250 WORDS)