Profile of natural Trypanosoma cruzi infection among dogs from rural areas of southern Espírito Santo, Brazil

BACKGROUND

The emergence of Trypanosoma cruzi infection via oral transmission has a habitual character in its primitive endemic cycle. Recent findings revealed the first death by oral transmission of T. cruzi in the state of Espírito Santo, Brazil, in 2012, which was recorded in the rural area of Guarapari. This study evaluated the characteristics related to the occurrence of natural T. cruzi infection among dogs from the rural areas of Alegre and Iconha, municipalities of Espírito Santo.

METHODS

Logistic regression analysis of factors contributing to serological detection of T. cruzi in dogs was performed in environments where Espírito Santo's Department of Health Surveillance had previously notified triatomines positive for Trypanosoma spp. from 2014 to 2017.

RESULTS

A total of 36 dogs were analyzed, of which 10 (27.77%) tested positive, one was borderline (2.79%), and 25 tested negative (69.44%) for T. cruzi infection. São Caetano, a district from the Iconha municipality, presented a 25 times greater chance for the detection of positive tests (OR:25; 95% CI; 2.37->100). Dogs with updated mandatory vaccination presented with a lower risk of positive serodiagnosis (OR:0.12; 95% CI: 0.02-0.63).

CONCLUSIONS

Our results highlight for the first time the occurrence of natural T. cruzi canine infection, detected in the municipality of Iconha, mainly among dogs with un-updated mandatory vaccines in the district of São Caetano.

Genome-Wide Analyses for Osteosarcoma in Leonberger Dogs Reveal the CDKN2A/B Gene Locus as a Major Risk Locus

Dogs represent a unique spontaneous cancer model. Osteosarcoma (OSA) is the most common primary bone tumor in dogs (OMIA 001441-9615), and strongly resembles human forms of OSA. Several large- to giant-sized dog breeds, including the Leonberger, have a greatly increased risk of developing OSA. We performed genome-wide association analysis with high-density imputed SNP genotype data from 273 Leonberger cases with a median age of 8.1 [3.1–13.5] years and 365 controls older than eight years. This analysis revealed significant associations at the CDKN2A/B gene locus on canine chromosome 11, mirroring previous findings in other dog breeds, such as the greyhound, that also show an elevated risk for OSA. Heritability (h²_SNP) was determined to be 20.6% (SE = 0.08; p-value = 5.7 × 10⁻⁴) based on a breed prevalence of 20%. The 2563 SNPs across the genome accounted for nearly all the h²_SNP of OSA, with 2183 SNPs of small effect, 316 SNPs of moderate effect, and 64 SNPs of large effect. As with many other cancers it is likely that regulatory, non-coding variants underlie the increased risk for cancer development. Our findings confirm a complex genetic basis of OSA, moderate heritability, and the crucial role of the CDKN2A/B locus leading to strong cancer predisposition in dogs. It will ultimately be interesting to study and compare the known genetic loci associated with canine OSA in human OSA.

Characterization of the Variables Related to Reports of Death Due to Canine Bites in Scientific Articles during the Years 2013-2017: A Systematic Review

Simple Summary

Dog bites are a major public health problem throughout the world. The main consequences for human health include physical and psychological injuries of varying proportions, secondary infections, sequelae, risk of transmission of zoonoses and surgery, among others, which entail costs for the health care system and those affected. The objective of this review was to search and analyze the indexed scientific literature on canine bites resulting in death, published during the period 2013–2017. The results show that most of the articles on bite accidents resulting in death analyzed in this study have details about the victims, their injuries and the treatment received by the victim. These results reflect that most of these accidents are suffered by adults, in public spaces and by only one animal. The analysis of these antecedents, as well as others incorporated in this review, will be of great help to fully understand the incidents of dog bites resulting in death published in the scientific literature.

Abstract

Canine bites are an important public health problem, with consequences such as physical injuries, psychological trauma, transmission of zoonoses, infections and they can even cause death. To avoid deaths caused by this type of bite, multiple factors related to this issue must be considered. The objective of this review was to search and analyze the indexed scientific literature on canine bites resulting in death, published during the period 2013–2017. A search was carried out in various databases of indexed literature, in Spanish and English. After selecting and excluding items using PRISMA, they were classified according to SIGN guidelines to filter out the level of evidence and potential biases. Thirty-three scientific articles were retrieved and analyzed. In most of these, victims between 50 and 64 years of age (28.6%, 8/28) were registered. Additionally, in most of the articles, only one animal participated (80%, 16/20). The highest number of events occurred in public spaces (58.5%, 7/12). In conclusion, most of the scientific articles that report incidents of dog bites resulting in death, provide details about the victims, their injuries and the treatment received; however, few articles provide background information on the context of the attack and the biting animal.

Dingo Density Estimates and Movements in Equatorial Australia: Spatially Explicit Mark-Resight Models

Australia is currently free of canine rabies. Spatio-ecological knowledge about dingoes in northern Australia is currently a gap that impedes the application of disease spread models and our understanding of the potential transmission of rabies, in the event of an incursion. We therefore conducted a one-year camera trap survey to monitor a dingo population in equatorial northern Australia. The population is contiguous with remote Indigenous communities containing free-roaming dogs, which potentially interact with dingoes. Based on the camera trap data, we derived dingo density and home range size estimates using maximum-likelihood, spatially explicit, mark-resight models, described dingo movements and evaluated spatial correlation and temporal overlap in activities between dingoes and community dogs. Dingo density estimates varied from 0.135 animals/km² (95% CI = 0.127-0.144) during the dry season to 0.147 animals/km² (95% CI = 0.135-0.159) during the wet season. The 95% bivariate Normal home range sizes were highly variable throughout the year (7.95-29.40 km²). Spatial use and daily activity patterns of dingoes and free-roaming community dogs, grouped over ~3 month periods, showed substantial temporal activity overlap and spatial correlation, highlighting the potential risk of disease transmission at the wild-domestic interface in an area of biosecurity risk in equatorial northern Australia. Our results have utility for improving preparedness against a potential rabies incursion.

Development of a Robust Canine Welfare Assessment Protocol for Use in Dog (Canis Familiaris) Catch-Neuter-Return (CNR) Programmes

Simple Summary

This paper describes the development of a robust composite welfare assessment tool to evaluate the welfare of free-roaming dogs passing through surgical sterilisation or catch-neuter-return (CNR) programmes. Catch-Neuter-Return programmes are frequently employed by governments and animal welfare charities to control the rising population of free-roaming dogs. Due to the focus on dog population control, individual dog welfare may be compromised through the CNR process, which comprises necessary stressors and harms, including capture, transport, surgery, and social disruption. Using a combination of a modified Delphi analysis and a Hazard Identification and a Critical Control Point analysis, this project described potential hazards to dog welfare during the CNR process and identified critical points where dog welfare could be assessed, and mitigations put in place to improve dog welfare throughout the CNR process. This project resulted in the development of a composite dog welfare assessment tool that will allow the robust assessment of the welfare of free-roaming dogs in CNR programmes and allow CNR projects to benchmark and mitigate hazards to dog welfare.

Abstract

The aim of this study was to develop a welfare assessment tool based on objective, reliable and relevant measures to be applied to individual dogs as they underwent a Catch-Neuter-Return (CNR) programme. A modified Delphi method and Hazard Analysis and Critical Control Points (HACCP) approach was used to develop the composite canine welfare assessment protocol, comprising both animal-based and resource-based measures. This draft welfare assessment protocol was then trialed and refined in existing CNR programmes to identify key control points where individual dog welfare may be moderately or significantly compromised in the CNR process. The results show that animal-based welfare indicators, e.g., pain behaviours, which provide a more direct indication of an animal’s welfare state, require training and skill to recognise, whilst resource-based indicators are simple to measure but act only as indirect measures of welfare. We concluded that whilst CNR projects can potentially improve the health and welfare of free-roaming dogs in the long-term, the risk of short-term welfare harms during the CNR process is high. Thus, it is essential for staff involved in dog population management programmes to assess the welfare state of dogs in CNR and take remedial action to safeguard individual dog welfare.

Behavioral and Self-report Measures Influencing Children's Reported Attachment to Their Dog

Despite the prevalence of dogs as family pets and increased scientific interest in canine behavior, few studies have investigated characteristics of the child or dog that influence the child-dog relationship. In the present study, we explored how behavioral and self-report measures influence a child's reported feelings of attachment to their dog, as assessed by the Lexington Attachment to Pets Scale (LAPS). We tested specifically whether children (N= 99; Age: M= 10.25 years, SD= 1.31 years) reported stronger attachment to dogs that were perceived as being more supportive (measured by a modified version of the Network of Relationships Inventory), to dogs that are more successful in following the child's pointing gesture in a standard two-object choice test, or to dogs that solicited more petting in a sociability assessment. In addition, we assessed whether children's attachment security to their parent, and whether being responsible for the care of their dog, influenced reported feelings of attachment to the dog. Overall, perceived support provided by the dog was highly predictive of all subscales of the LAPS. The dog's success in following the child's pointing gesture and lower rates of petting during the sociability assessment were associated with higher ratings on the general attachment subscale of the LAPS, but not of other subscales of the LAPS. Caring for the dog did not predict the child's reported attachment to dog, but did predict the dog's behavior on the point following task and petting during the sociability task. If the child cared for the dog, the dog was more likely to be successful on the pointing task and more likely to be petted. These results indicate a dyadic relationship in which the child's care for the dog is associated with the dog's behavior on the behavioral tasks, which in turn is related to the child's reported feelings of attachment. The direction of influence and nature of this dyad will be a fruitful area for future research.

A RAB3GAP1 SINE Insertion in Alaskan Huskies with Polyneuropathy, Ocular Abnormalities, and Neuronal Vacuolation (POANV) Resembling Human Warburg Micro Syndrome 1 (WARBM1)

We observed a hereditary phenotype in Alaskan Huskies that was characterized by polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV). The affected dogs developed a progressive severe ataxia, which led to euthanasia between 8 and 16 months of age. The pedigrees were consistent with a monogenic autosomal recessive inheritance. We localized the causative genetic defect to a 4 Mb interval on chromosome 19 by a combined linkage and homozygosity mapping approach. Whole genome sequencing of one affected dog, an obligate carrier, and an unrelated control revealed a 218-bp SINE insertion into exon 7 of the RAB3GAP1 gene. The SINE insertion was perfectly associated with the disease phenotype in a cohort of 43 Alaskan Huskies, and it was absent from 541 control dogs of diverse other breeds. The SINE insertion induced aberrant splicing and led to a transcript with a greatly altered exon 7. RAB3GAP1 loss-of-function variants in humans cause Warburg Micro Syndrome 1 (WARBM1), which is characterized by additional developmental defects compared to canine POANV, whereas Rab3gap1-deficient mice have a much milder phenotype than either humans or dogs. Thus, the RAB3GAP1 mutant Alaskan Huskies provide an interesting intermediate phenotype that may help to better understand the function of RAB3GAP1 in development. Furthermore, the identification of the presumed causative genetic variant will enable genetic testing to avoid the nonintentional breeding of affected dogs.