Prime Editor-mediated Correction of a Pathogenic Mutation in Purebred Dogs

Canine hip dysplasia (HD) is a multifactorial disease caused by interactions between genetic and environmental factors. HD, which mainly occurs in medium- to large-sized dogs, is a disease that causes severe pain and requires surgical intervention. However, the procedure is not straight-forward, and the only way to ameliorate the situation is to exclude individual dogs with HD from breeding programs. Recently, prime editing (PE), a novel genome editing tool based on the CRISPR-Cas9 system, has been developed and validated in plants and mice. In this study, we successfully corrected a mutation related to HD in Labrador retriever dogs for the first time. We collected cells from a dog diagnosed with HD, corrected the mutation using PE, and generated mutation-corrected dogs by somatic cell nuclear transfer. The results indicate that PE technology can potentially be used as a platform to correct genetic defects in dogs.

Genes of Congenital Dermatologic Disorders in Dogs—A Review

This article presents an overview of up-to-date identified genes responsible for congenital canine skin diseases of dogs and the characteristics of these diseases. Congenital skin diseases constitute a specific group of dermatologic disorders that plays an important role in breeding of purebred dogs. They include primary seborrhoea, ichthyosis, hereditary nasal parakeratosis, dermatomyositis, colour dilution alopecia, skin mucinosis, dermoid sinus, lethal acrodermatitis, acral mutilation syndrome, keratoconjunctivitis sicca, ichthyosiform dermatosis, bullous epidermolysis, exfoliative dermal lupus erythematosus, congenital footpad hyperkeratosis and sebaceous adenitis. In the majority of cases, their occurrence is linked to particular breeds. In more than half of these diseases a specific defective gene variant responsible for the disease has been identified. Genetic tests for identification of the relevant defective genes serve as an important tool in the diagnostics of diseases in veterinary practice and in breeding of purebred dogs.

Factors Affecting Human-Directed Aggression Resulting in Dog Bites: Contextual Aspects of the Biting Incidents

Using a web-based questionnaire with 29 close- and open-ended questions about 400 self-reported dog-biting incidents in Slovenia, this research investigated the contexts of dog bites, focusing on characteristics of the dogs and the descriptions of the situations to identify the main risk factors for the occurrence of dog bites. Even though it has been suggested that most dog bites occur during initially non-aggressive interactions with the dog (e.g., during petting, playing), in our study we discerned a wide variety of contexts, including those in which the person did not intend to interact with the dog. Most victims reported unprovoked bites during fast movements near the dog, while coming into close proximity, and during incidents without a reason. These incidents more likely occurred in public than private places and were associated with purebred dogs with a history of aggression.

INFLAMMATORY-DESTRUCTIVE PROCESS IN PERIODONTIUM WHILE MODELLING HYPО- AND HYPERREACTIVITY OF THE ORGANISM

The issues of clarifying the key mechanisms of development and course of generalized periodontitis in different conditions of reactivity of the organism remain relevant. The aim of the research is study of the peculiarities of course of the inflammatory-destructive process in the periodontium according to the dynamics of clinical and paraclinical indicators depending on the state of reactivity of the body in the conditions of modeling hyper- and hyporeaction. Materials and methods. The experiments were performed on 24 adult not purebred dogs weighing 8-12 kg. The animals were divided into three equal groups. In the first group, drugs that disrupt the reactivity of the organism were not used (normoreactivity of the organism). In the second group drugs simulated the state of hyperreactivity, and in the third they provoked the condition of the hyporeactivity of the organism. The condition of periodontal tissues was assessed initially, on the 14th and 28th day of observation of clinical and paraclinical parameters (creviculars liquor, PMA indices, PI Russell, GI Fedorov-Volodkina, Kulazhenko's test). Results. On the 14th day of modelling the states of hyper- and hyporeactivity of the organism a number of differences in the nature of inflammation in periodontal tissues were revealed in animals of different groups. Control of the amount of creviculars liquor increased in 1,1 times, PMA indices, PI Russell, GI Fedorov-Volodkina, Kulazhenko's test, respectively, in 1,12; 1,19; 1,33 and 1,29 times (p <0,05). On the 28th day of the experiment, significant differences in the intensity of the destructive process in animals with unchanged and changed reactivity of the organism attracted attention. Thus, in cases of normoreactivity the depth of periodontal pockets reached 3 mm, the mobility of the teeth was I degree, with the changed - the depth of periodontal pockets was 5-6 mm, the mobility of the teeth was II-III degree. The amount of creviculars liquor, reflecting the intensity of the inflammatory reaction, increased compared with the 14th day, 1,3 times (p <0,05); PMA index, which characterizes the prevalence of gingivitis, and the Kulazhenko test probably did not change (p> 0,05); Russell's PI index, which indicates a pronounced intensity of inflammatory-destructive periodontal lesions, increased 2,05 times (р <0,05). Conclusions. Thus, in cases of normoreactivity of organism the inflammatory-destructive process in periodontium has moderate nature; when modelling the hyper- and hyporeactivity of the organism it acquires the character of “rapidly progressing periodontitis”. Therefore, it is necessary to continue studying the question of explaining the mechanism of different clinical course of the inflammatory-destructive process with changed and unchanged reactivity of the organism.

Allele and genotype frequencies of the SOD1 gene polymorphism associated with canine degenerative myelopathy in Belgian Malinois dogs in Greece

Background and Aim: Canine degenerative myelopathy (CDM) is an adult-onset fatal disorder associated with a point mutation of the superoxide dismutase 1 (SOD1) gene (SOD1:c.118G>A). This study aimed to determine the allele and genotype frequencies of this mutation in a group of Belgian Malinois dogs in Greece. Materials and Methods: Samples (n=72) of whole blood were collected from 72 purebred dogs of the Hellenic Armed Forces; these samples were processed for DNA isolation, polymerase chain reaction, and digestion with the restriction endonuclease AcuI. Sample testing was conducted in compliance with ISO17025 accreditation requirements. Results: The observed relative genotype frequencies were 71% for the homozygous (GG), 25% for the heterozygous (AG), and 4% for the homozygous mutant (AA) alleles. These frequencies were close to those expected, indicating no significant departure from Hardy–Weinberg equilibrium (HWE, p=0.395). The frequency of heterozygous animals indicates that a high risk of developing CDM in forthcoming generations exists in the tested population because mating among carriers would result in 25% AA progeny. The medical record of the group of study animals indicated selection against leishmaniosis, as applied throughout generations by owners and breeders. The potential association of this selection with the HWE status of the study population was discussed. Conclusion: The SOD1:c.118G>A mutation was common in the tested group of dogs; thus, they are suitable for a follow-up investigation on the development and progression of CDM. A case-control study on animals with evidence of sensitivity to infectious myelopathy could provide new insights into disease pathogenesis.

Aggressive behaviour is affected by demographic, environmental and behavioural factors in purebred dogs

Aggressive behaviour is an unwanted and serious problem in pet dogs, negatively influencing canine welfare, management and public acceptance. We aimed to identify demographic and environmental factors associated with aggressive behaviour toward people in Finnish purebred pet dogs. We collected behavioural data from 13,715 dogs with an owner-completed online questionnaire. Here we used a dataset of 9270 dogs which included 1791 dogs with frequent aggressive behaviour toward people and 7479 dogs without aggressive behaviour toward people. We studied the effect of several explanatory variables on aggressive behaviour with multiple logistic regression. Several factors increased the probability of aggressive behaviour toward people: older age, being male, fearfulness, small body size, lack of conspecific company, and being the owner’s first dog. The probability of aggressive behaviour also differed between breeds. These results replicate previous studies and suggest that improvements in the owner education and breeding practices could alleviate aggressive behaviour toward people while genetic studies could reveal associated hereditary factors.

Presence of Campylobacter jejuni and C. coli in Dogs under Training for Animal-Assisted Therapies

This study was conducted to evaluate the presence of Campylobacter (C.) jejuni and C. coli in dogs at five dog training centers in Southern Italy. A total of 550 animals were sampled by collecting rectal swabs. The samples were processed to detect thermotolerant Campylobacter spp. by culture and molecular methods. Campylobacter spp. were isolated from 135/550 (24.5–95% confidence interval) dogs. A total of 84 C. jejuni (62.2%) and 51 C. coli (37.8%) isolates were identified using conventional PCR. The dog data (age, sex, breed, and eating habits) were examined by two statistical analyses using the C. jejuni and C. coli status (positive or negative) as dependent variables. Dogs fed home-cooked food showed a higher risk of being positive for C. jejuni than dogs fed dry or canned meat for dogs (50.0%; p < 0.01). Moreover, purebred dogs had a significantly higher risk than crossbred dogs for C. coli positivity (16.4%; p < 0.01). This is the first study on the prevalence of C. jejuni and C. coli in dogs frequenting dog training centers for animal-assisted therapies (AATs). Our findings emphasize the potential zoonotic risk for patients and users involved in AATs settings and highlight the need to carry out ad hoc health checks and to pay attention to the choice of the dog, as well as eating habits, in order to minimize the risk of infection.

Mortality Resulting from Undesirable Behaviours in Dogs Aged Three Years and under Attending Primary-Care Veterinary Practices in Australia

There is increasing evidence that undesirable behaviours (UBs) in dogs can compromise the welfare of both canine companions and their carers. Veterinarians are regularly consulted about affected animals and may be asked to euthanase the more severely affected individuals. A recent study of veterinary records showed that UBs were the predominant cause of mortality in young dogs in the UK. This companion study from Australia reports the proportion of mortality due to UBs among dogs aged three years and under that attended veterinary practices from 2013 to 2018. Deidentified patient records were extracted from the VetCompass Australia database and manually assessed to reveal the prevalence and type of UBs reported. The results reveal that 29.7% of the 4341 dogs that died at three years of age or under had deaths ascribed to at least one UB, and that the most commonly reported UB was aggression. Neutered dogs had 2.5× the odds of death due to an UB compared to intact dogs, and crossbred dogs were found to have 1.43× the odds of a UB related death compared to purebred dogs. The breeds at highest risk were Australian cattle dogs (odds ratio (OR) 4.77) and American Staffordshire terriers (OR 4.69). The attending veterinarian referred behaviour cases to a behaviourist or dog trainer in 11.0% of all UB cases, and attempted pharmacological therapy in 5.9% of cases. The results reveal how often UBs affect dogs and their owners in Australia, and infer the beneficial impact that educating dog owners and veterinary professionals in modifying and managing UBs may have.