Analysis of canine parvoviruses circulating in Australia reveals predominance of variant 2b and identifies feline parvovirus-like mutations in the capsid proteins.

Canine parvovirus (CPV) is a major enteric pathogen of dogs worldwide that emerged in the late 1970s from a feline parvovirus (FPV)-like ancestral virus. Shortly after its emergence, variant CPVs acquired amino acid (aa) mutations in key capsid residues, associated with biological and/or antigenic changes. This study aimed to identify and analyse CPV variants and their capsid mutations amongst Australian dogs, to gain insights into the evolution of CPV in Australia and to investigate relationships between the disease and vaccination status of dogs from which viruses were detected. CPV VP2 sequences were amplified from 79 faecal samples collected from dogs with parvoviral enteritis at 20 veterinary practices in five Australian states. The median age at diagnosis was 4 months (range 1-96 months). Only 3.7% of dogs with vaccination histories had completed recommended vaccination schedules, while 49% were incompletely vaccinated and 47.2% were unvaccinated. For the first time, CPV-2b has emerged as the dominant antigenic CPV variant circulating in dogs with parvoviral enteritis in Australia, comprising 54.4% of viruses, while CPV-2a and CPV-2 comprised 43.1% and 2.5%, respectively. The antigenic variant CPV-2c was not identified. Analysis of translated VP2 sequences revealed a vast repertoire of amino acid (aa) mutations. Several Australian CPV strains displayed signatures in the VP2 protein typical of Asian CPVs, suggesting possible introduction of CPV strains from Asia, and/or CPV circulation between Asia and Australia. Canine parvoviruses were identified containing aa residues typical of FPV at key capsid (VP2) positions, representing reverse mutations or residual mutations retained from CPV-2 during adaptation from an FPV-like ancestor, suggesting that evolutionary intermediates between CPV-2 and FPV are circulating in the field. Similarly, intermediates between CPV-2a-like viruses and CPV-2 were also identified. These findings help inform a better understanding of the evolution of CPV in dogs.

Phylogenetic and Geospatial Evidence of Canine Parvovirus Transmission between Wild Dogs and Domestic Dogs at the Urban Fringe in Australia.

Canine parvovirus (CPV) is an important cause of disease in domestic dogs. Sporadic cases and outbreaks occur across Australia and worldwide and are associated with high morbidity and mortality. Whether transmission of CPV occurs between owned dogs and populations of wild dogs, including Canis familiaris, Canis lupus dingo and hybrids, is not known. To investigate the role of wild dogs in CPV epidemiology in Australia, PCR was used to detect CPV DNA in tissue from wild dogs culled in the peri-urban regions of two Australian states, between August 2012 and May 2015. CPV DNA was detected in 4.7% (8/170). There was a strong geospatial association between wild-dog CPV infections and domestic-dog CPV cases reported to a national disease surveillance system between 2009 and 2015. Postcodes in which wild dogs tested positive for CPV were 8.63 times more likely to also have domestic-dog cases reported than postcodes in which wild dogs tested negative (p = 0.0332). Phylogenetic analysis of CPV VP2 sequences from wild dogs showed they were all CPV-2a variants characterized by a novel amino acid mutation (21-Ala) recently identified in CPV isolates from owned dogs in Australia with parvoviral enteritis. Wild-dog CPV VP2 sequences were compared to those from owned domestic dogs in Australia. For one domestic-dog case located approximately 10 km from a wild-dog capture location, and reported 3.5 years after the nearest wild dog was sampled, the virus was demonstrated to have a closely related common ancestor. This study provides phylogenetic and geospatial evidence of CPV transmission between wild and domestic dogs in Australia.

Socioeconomic, geographic and climatic risk factors for canine parvovirus infection and euthanasia in Australia.

Infection of canids with canine parvovirus (CPV) can result in severe, often fatal disease. This study aimed to examine climatic, socioeconomic and geographic risk factors for CPV infection and CPV-associated euthanasia in Australia. Australian veterinary hospital responses (534; 23.5 %) to a national veterinary survey of CPV case occurrences and euthanasias in 2016 were used. Severe caseloads (>40 cases per annum) were reported by 26 (11 %) hospitals (median 60 cases; IQR 50-110). Case reporting, case numbers, and without-treatment euthanasia were significantly associated with disadvantage across all Socio-Economic Index for Areas quintiles (p < 0.0001) - the greater the disadvantage, the more reports. Strong negative correlations were found between case numbers and the Index of Relative Socioeconomic Disadvantage (rSP = -0.3357, p < 0.0001) and also between euthanasia and the Index of Education and Occupation (rSP = -0.3762, p < 0.0001). Hospitals in more remote areas were also more likely to report cases and to euthanize without treatment (p < 0.0001). Of the climate variables, temperature of the hottest month was most strongly positively correlated with case numbers (rSP = 0.421, p < 0.0001), and lower annual rainfall was associated with more case-reporting hospitals (p < 0.0001). These results confirm that socioeconomic disadvantage is a significant risk-factor for CPV infection and outcome, and high temperature may also contribute to risk.

Distinct Lineages of Feline Parvovirus Associated with Epizootic Outbreaks in Australia, New Zealand and the United Arab Emirates.

Feline panleukopenia (FPL), a frequently fatal disease of cats, is caused by feline parvovirus (FPV) or canine parvovirus (CPV). We investigated simultaneous outbreaks of FPL between 2014 and 2018 in Australia, New Zealand and the United Arab Emirates (UAE) where FPL outbreaks had not been reported for several decades. Case data from 989 cats and clinical samples from additional 113 cats were obtained to determine the cause of the outbreaks and epidemiological factors involved. Most cats with FPL were shelter-housed, 9 to 10 weeks old at diagnosis, unvaccinated, had not completed a primary vaccination series or had received vaccinations noncompliant with current guidelines. Analysis of parvoviral VP2 sequence data confirmed that all FPL cases were caused by FPV and not CPV. Phylogenetic analysis revealed that each of these outbreaks was caused by a distinct FPV, with two virus lineages present in eastern Australia and virus movement between different geographical locations. Viruses from the UAE outbreak formed a lineage of unknown origin. FPV vaccine virus was detected in the New Zealand cases, highlighting the difficulty of distinguishing the co-incidental shedding of vaccine virus in vaccinated cats. Inadequate vaccination coverage in shelter-housed cats was a common factor in all outbreaks, likely precipitating the multiple re-emergence of infection events.

The relationship between reported domestic canine parvovirus cases and wild canid distribution.

Canine parvovirus (CPV) is an important and often fatal pathogen of domestic dogs. It is resistant in the environment and cross-species transmission has been indicated in some canid populations, but never in Australia. The aim of this study was to determine if an association exists between 1. reported CPV cases in domestic dogs, and 2. the wild canid distribution in New South Wales (NSW), Australia. Reported CPV cases, and reports of the presence of wild dogs and the red fox (Vulpes vulpes), were extracted from a voluntary surveillance database and a voluntary pest reporting system, respectively. A total of 1,984 CPV cases in domestic dogs, and 3,593 fox and 3,075 wild dog sightings were reported between 2011 and 2016. Postcodes in which CPV cases were reported were significantly (P = 0.0002) more likely to report wild dogs (odds ratio 2.07, 95% CI 1.41-3.03). Overall, CPV cases were significantly (P < 0.05) correlated with both fox reports (rSP 0.225) and wild dog reports (rSP 0.247). The strength of association varied by geographical region and year; the strongest correlations were found in the mid-North Coast region (rSP 0.607 for wild dogs) and in 2016 (rSP 0.481 for foxes). Further serological and virological testing is required to confirm the apparent and plausible association between domestic CPV cases and wild canid distribution found in this study.

Risk of Feline Immunodeficiency Virus (FIV) Infection in Pet Cats in Australia is Higher in Areas of Lower Socioeconomic Status.

Feline immunodeficiency virus (FIV), feline calicivirus (FCV), and feline herpesvirus (FHV-1) are common viral infections of domestic cats in Australia. A study was performed to investigate the possible effect of area-based socioeconomic factors on the occurrence of FIV, FCV, and FHV-1 infection in Australian client-owned cats. A total of 1044 cases, reported to a voluntary Australian online disease surveillance system between January 2010 and July 2017, were analysed with respect to their postcode-related socioeconomic factors using the Socio-Economic Indexes For Areas (SEIFA). SEIFA consists of four different indexes which describe different aspects of socioeconomic advantage and disadvantage. Signalment details including age, sex, neuter status, and breed were also considered. A significant correlation was observed between areas of lower socioeconomic status and a higher number of reported cases of FIV infection for all four SEIFA indexes (p ≤ 0.0002). Postcodes with SEIFA indexes below the Australian median ("disadvantaged" areas) were 1.6-2.3 times more likely to have reported cases of FIV infection than postcodes with SEIFA indexes above the median ("advantaged" areas). In contrast, no correlation was observed between the number of reported cases of FCV or FHV-1 infection and any of the four SEIFA indexes (p > 0.05). When signalment data were analysed for the three infections, FIV-infected cats were more likely to be older (p < 0.00001), male (p < 0.0001), neutered (p = 0.03), and non-pedigree (p < 0.0001) compared to FCV and FHV-1 infected cats. Results from this study suggest that area-based disease control strategies, particularly in areas of social disadvantage, might be effective in reducing the prevalence of FIV infection in pet cats in Australia.

Feline upper respiratory tract infection and disease in Australia.

OBJECTIVES: The aim of this study was to conduct a comprehensive assessment of feline infectious upper respiratory tract infection (URTI) and disease (URTD) in Australian cats. METHODS: Laboratory data demonstrating URTI from feline URTD multiplex PCR panel (feline herpesvirus 1 [FHV-1], feline calicivirus [FCV], Bordetella bronchiseptica, Chlamydophila felis, Mycoplasma felis and H1N1 influenza) submissions in Australia (2013-2015) were obtained. For comparison, reports of feline URTD during the same time period were sourced from a voluntary companion animal disease surveillance system. RESULTS: A total of 3126 samples were submitted for testing; 1533 (49%) were positive. Of these, the most commonly detected agents were M felis (21.5%) and FCV (16.0%) alone, followed by FCV and M felis (13.4%) together as a respiratory infection complex, then FHV-1 (7.0%) alone. During the study period, there were 262 reports of 320 clinical feline URTD cases. Most cases (69%) were reported from New South Wales, <1 year of age (41%) and equally distributed between the sexes. Infection was more common in entire cats (69%) and most cases (55%) involved domestic shorthair cats. Of the 90 reports that had a known vaccination status, 63 had a vaccination history, 40 of which were recently vaccinated. Most (72%) feline URTD cases recovered from clinical disease. Both feline URTI and URTD were more common during winter months. CONCLUSIONS AND RELEVANCE: Feline URTI and URTD cause substantial impact in Australia, being most commonly associated with M felis and FCV infection. This information can be used by veterinarians to educate clients about prevention and management of this important infectious disease of cats.

The geographic distribution and financial impact of canine parvovirus in Australia.

Canine parvovirus (CPV) is an important cause of serious and often fatal disease in dogs worldwide, however, a national survey of CPV cases in Australia has not been conducted since 1982. For this study we surveyed the entire Australian veterinary clinic population and achieved a response rate of 23.5% (534 unique veterinary clinics). Respondents reported 4,451 CPV cases in 2015 and 4,219 cases in 2016; the estimated total CPV case load across Australia was 20,661 in 2015 and 20,110 in 2016. The overall reported euthanasia rate was 41%. Geospatial analysis revealed large numbers of CPV cases in rural and remote areas of Australia. Where cases occurred in capital city areas, these were found in peri-urban areas, away from the inner city. The median cost to treat CPV cases was $A1,500 per patient. A significant difference in the cost of treating cases was found between Australian states; Western Australia (median $A2,500) was the most expensive state. There was a strong correlation between cost of treatment and rate of euthanasia without treatment reflecting the important role of affordability in disease-related euthanasia. These findings highlight the considerable impact of the evolving CPV situation in Australia, particularly in regional and rural areas. This survey is the most comprehensive epidemiological investigation of canine parvoviral-related disease, to date, globally and provides a process for national disease surveillance.

Are recreational areas a risk factor for tick paralysis in urban environments?

In Australia, tick paralysis in dogs (caused by a toxin in the saliva of Ixodes species during feeding) is a serious, distressing condition, and untreated it is often fatal. The aim of this study was to quantify the association between parkland (recreational or natural) in an urban area and the occurrence of canine tick paralysis. Brisbane, as a large urban centre located within the zone of paralysis tick habitat along the east coast of Australia, was selected as the study area. Postcodes selected for inclusion were those defined as being of an urban character (Australian Bureau of Statistics). The number of natural and recreational parkland polygons and total land area per postcode were derived. Tick paralysis case data for the selected postcodes were extracted from a national companion animal disease surveillance database. Between October 2010 and January 2017, 1650 cases of tick paralysis in dogs were reported and included in this study. Significant correlations were found between the number of reported cases per postcode and parklands: natural counts, 0.584 (P < 0.0001); natural area, 0.293 (P = 0.0075); recreational counts, 0.297 (P = 0.0151); and recreational area, 0.241 (P = 0.0286). Four disease clusters were also detected within the study area. All of these were located on the edges of the study area - either coastal or on the urban fringe; no clusters were identified within the core urban zone of the study area. Of the disease cases included in this study, strong seasonality was evidence: 68% of all cases were identified in spring. Within urban environments, areas of natural vegetation in particular appear to pose a risk for tick paralysis in dogs. This evidence can be used by veterinarians and dog owners to reduce the impact of tick paralysis by raising awareness of risk areas so as to enhance prevention via chemoprophylaxis and targeted searches of pet dogs for attached ticks.

Delineation of an endemic tick paralysis zone in southeastern Australia.

Tick paralysis has a major impact on pet dog and cat populations in southeastern Australia. It results from envenomation by Ixodes holocyclus and Ixodes cornuatus ticks, the role of Ixodes cornuatus in the epidemiology of this disease in Australia being unclear. The aim of this study was to describe the geographical distribution of tick paralysis cases in southeastern Australia using data from a national disease surveillance system and to compare characteristics of "endemic" cases with those reported outside this endemic zone ("sporadic" cases). Data were collated and a proportional symbol map of all cases by postcode was created. A 15-case isopleth was developed based on descriptive spatial statistics (directional ellipses) and then kernel smoothing to distinguish endemic from sporadic cases. During the study period (January 2010-December 2015) 12,421 cases were reported, and 10,839 of these reported by clinics located in 434 postcodes were included in the study. Endemic cases were predominantly reported from postcodes in coastal southeastern Australia, from southern Queensland to eastern Victoria. Of those cases meeting selection criteria, within the endemic zone 10,767 cases were reported from 351 (88%) postcodes and outside this zone 72 cases were reported from 48 (12%) postcodes. Of these latter 48 postcodes, 18 were in Victoria (26 cases), 16 in New South Wales (28 cases), 7 in Tasmania (9 cases), 5 in South Australia (7 cases) and 2 in Queensland (2 cases). Seasonal distribution in reporting was found: 62% of endemic and 52% of sporadic cases were reported in spring. The number of both endemic and sporadic cases reported peaked in October and November, but importantly a secondary peak in reporting of sporadic cases in April was found. In non-endemic areas, summer was the lowest risk season whilst in endemic areas, autumn was the lowest risk season. Two clusters of sporadic cases were identified, one in South Australia (P=0.022) during the period 22 May to 2 June 2012 and another in New South Wales (P=0.059) during the period 9 October to 29 November 2012. Endemic and sporadic cases did not differ with respect to neuter status (P=0.188), sex (P=0.205), case outcome (P=0.367) or method of diagnosis (P=0.413). However, sporadic cases were 4.2-times more likely to be dogs than cats (P<0.001). The endemic tick paralysis zone described is consistent with previous anecdotal reports. Sporadic cases reported outside this zone might be due to a history of pet travel to endemic areas, small foci of I. holocyclus outside of the endemic zone, or in the case of southern areas, tick paralysis caused by I. cornuatus.

The Choice Between Total Hip Arthroplasty and Arthrodesis in Adolescent Patients: A Survey of Orthopedic Surgeons.

For adolescent patients with end-stage hip disease, the choice between total hip arthroplasty (THA) and arthrodesis is complex; the clinical evidence is not definitive, and there are difficult trade-offs between clear short-term benefits from THA and uncertain long-term risks. We surveyed nearly 700 members of the Pediatric Orthopedic Society of North America and the American Association of Hip and Knee Surgeons. Respondents chose between a recommendation of THA or arthrodesis in four clinical vignettes. A clear majority of surgeons recommended THA in two of the vignettes, however opinion was somewhat divided in one vignette (overweight adolescent) and deeply divided in another (adolescent destined for manual labor job). Across all vignettes, recommendations varied systematically according to surgeons' age and their attitudes regarding tradeoffs between life stages.

Canine parvovirus in Australia: A comparative study of reported rural and urban cases.

Canine parvovirus (CPV) is a highly contagious and often fatal disease reported worldwide. Outbreaks occur throughout Australia, and it has been suggested that disproportionally more CPV cases occur in rural locations. However, evidence to support this suggestion-and possible reasons for such a predisposition-has not existed until now. In this study a total of 4870 CPV cases reported from an Australian disease surveillance system between September 2009 and July 2014 were analysed. Australian postcodes were classified as rural or urban (based on human population density) and reported CPV cases were then categorised as rural or urban based on their reported home postcode. Parvovirus cases were predominately young (<12 months), entire, unvaccinated, mixed-breed dogs. More than twice as many of the reported cases were from a rural area (3321 cases) compared to an urban area (1549 cases). The overall case fatality rate was 47.2%; it was higher for those CPV cases reported from urban areas (50.6%) than rural areas (45.5%). A greater proportion of rural cases were younger, entire dogs compared to urban cases. The final multivariable model of CPV cases being reported from a rural area included age (<12 months) and vaccination status (never vaccinated) as significant predictors. Poor socioeconomic status might be a reason for the decision of rural owners not to vaccinate their dogs as readily as urban owners. The excess reporting of rural CPV cases compared to urban cases and the predictive risk factors identified in this study can be used by veterinarians to reduce the incidence of CPV by educating owners about the disease and promoting better vaccination programs in rural areas. This study also supports that the increased risk of CPV in rural areas may necessitate a need for increased vigilance around preventing CPV disease spread, additional care with puppies which are the most susceptible to this disease and tighter vaccination protocols, compared to urban areas.

The relationship between the Southern Oscillation Index, rainfall and the occurrence of canine tick paralysis, feline tick paralysis and canine parvovirus in Australia.

The aim of this study was to describe the association between climate, weather and the occurrence of canine tick paralysis, feline tick paralysis and canine parvovirus in Australia. The Southern Oscillation Index (SOI) and monthly average rainfall (mm) data were used as indices for climate and weather, respectively. Case data were extracted from a voluntary national companion animal disease surveillance resource. Climate and weather data were obtained from the Australian Government Bureau of Meteorology. During the 4-year study period (January 2010-December 2013), a total of 4742 canine parvovirus cases and 8417 tick paralysis cases were reported. No significant (P ≥ 0.05) correlations were found between the SOI and parvovirus, canine tick paralysis or feline tick paralysis. A significant (P < 0.05) positive cross-correlation was found between parvovirus occurrence and rainfall in the same month (0.28), and significant negative cross-correlations (-0.26 to -0.36) between parvovirus occurrence and rainfall 4-6 months previously. Significant (P < 0.05) negative cross-correlations (-0.34 to -0.39) were found between canine tick paralysis occurrence and rainfall 1-3 months previously, and significant positive cross-correlations (0.29-0.47) between canine tick paralysis occurrence and rainfall 7-10 months previously. Significant positive cross-correlations (0.37-0.68) were found between cases of feline tick paralysis and rainfall 6-10 months previously. These findings may offer a useful tool for the management and prevention of tick paralysis and canine parvovirus, by providing an evidence base supporting the recommendations of veterinarians to clients thus reducing the impact of these diseases.

The association between landscape and climate and reported tick paralysis cases in dogs and cats in Australia.

The aim of this study was to describe the association between landscape and climate factors and the occurrence of tick paralysis cases in dogs and cats reported by veterinarians in Australia. Data were collated based on postcode of residence of the animal and the corresponding landscape (landcover and elevation) and climate (precipitation, temperature) information was derived. During the study period (October 2010-December 2012), a total of 5560 cases (4235 [76%] canine and 1325 [24%] feline cases) were reported from 341 postcodes, mostly along the eastern seaboard of Australia and from the states of New South Wales and Queensland. Significantly more cases were reported from postcodes which contained areas of broadleaved, evergreen tree coverage (P=0.0019); broadleaved, deciduous open tree coverage (P=0.0416); and water bodies (P=0.0394). Significantly fewer tick paralysis cases were reported from postcodes which contained areas of sparse herbaceous or sparse shrub coverage (P=0.0297) and areas that were cultivated and managed (P=0.0005). No significant (P=0.6998) correlation between number of tick paralysis cases reported per postcode and elevation was found. Strong positive correlations were found between number of cases reported per postcode and the annual minimum (rSP=0.9552, P<0.0001) and maximum (rSP=0.9075; P=0.0001) precipitation. Correlations between reported tick paralysis cases and temperature variables were much weaker than for precipitation, rSP<0.23. For maximum temperature, the strongest correlation between cases was found in winter (rSP=0.1877; P=0.0005) and for minimum temperature in autumn (rSP=0.2289: P<0.0001). Study findings suggest that tick paralysis cases are more likely to occur and be reported in certain eco-climatic zones, such as those with higher rainfall and containing tree cover and areas of water. Veterinarians and pet owners in these zones should be particularly alert for tick paralysis cases to maximize the benefits of early treatment, and to be vigilant to use chemical prophylaxis to reduce the risk of tick parasitism.

Risk factors for death from canine parvoviral-related disease in Australia.

Canine parvovirus (CPV) is a highly contagious cause of serious and often fatal disease in dogs worldwide despite the availability of safe and efficacious vaccines. Although a number of studies have focussed on identifying risk factors in disease development, risk factors associated with death from CPV are largely unknown. In this study we analysed a total of 1451 CPV cases reported from an Australian surveillance system - using univariate and multivariate techniques - to determine significant risk factors associated with death and euthanasia. A crude case fatality rate of 42.3% was estimated - higher than has been reported previously. We found that 3.3% of CPV cases had a history of vaccination in the previous 12 months, despite having completed the primary puppy vaccination course. The majority (89.5%) of these cases occurred in dogs <12 months of age, indicating failure of the primary vaccination course to provide protective immunity (most likely due to interference of the vaccine antigen with maternal antibodies but other reasons are discussed). Extending the age at which the final puppy vaccination is administered might be one of several strategies to consider. The final multivariate model showed that in non-litter CPV cases, risk of death was significantly associated with season of diagnosis (summer) and pedigree type (hounds and non-sporting dogs). Euthanasia in non-litter CPV cases was significantly associated with season of diagnosis (summer), state of residence (Northern Territory/South Australia/Tasmania combined), age (

Surgeon age as the major factor in recommendation of uni-compartmental knee replacement versus high tibial osteotomy: a case study in orthopaedic decision making.

This case report concerns surgical decision making. The subject is a 59 year old male orthopaedic surgeon with medial compartment knee arthritis. Both high tibial valgus osteotomy and uni-compartmental knee replacement would be appropriate with similar outcomes reported in the literature. Surprisingly, almost all young surgeons recommended a uni-compartmental knee replacement and almost all older surgeons recommended a high tibial osteotomy. We discuss the reasons that surgeon age, which is clearly irrelevant to the optimal decision, is the dominant determinant of surgical recommendation for this patient.