Dog Samples Research Articles

The Effect of Ethyl Esters of Linseed Oil on the Changes in the Fatty Acid Profile of Hair Coat Sebum, Blood Serum and Erythrocyte Membranes in Healthy Dogs.

The aim of this study was to determine the effect of supplementation with ethyl esters of linseed oil on the fatty acid profile in hair sebum, blood serum and erythrocyte membranes in healthy dogs. The material for the study included hair and blood samples of adult beagle dogs. The experiment was performed in two periods: summer and winter. Each time it lasted 16 weeks. During the first 8 weeks, the dogs received a supplement, the amount of which was determined individually so that the ratio of α-linolenic acid (ALA) to linoleic acid (LA) together in the feed and supplement was 1:1. Hair coat and blood samples were collected on days 0, 56 and 112; i.e., before the start of supplementation, after 8 weeks of supplementation and 8 weeks after supplementation was completed. The study included a determination of the fatty acid profile with a particular emphasis on polyunsaturated fatty acids (PUFAs) and the ratio of omega-6 to omega-3 in hair sebum, blood serum and erythrocyte membranes. As a result of supplementation, a significant decrease in saturated acids and an increase in unsaturated acids was observed in hair sebum both in summer and winter and especially in omega-3 fatty acids; i.e., α-linolenic (ALA) and its derivatives eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The same relationships were observed in blood serum and in erythrocyte cell membranes in all the studied periods. Additionally, 8 weeks after the end of supplementation, the level of polyunsaturated fatty acids was still higher compared to the period before supplementation. Moreover, the supplementation resulted in a favorable decrease in the ratio of omega-6 to omega-3 acids in the tested samples, which persisted even after the withdrawal period.

Specific and label-free endogenous signature of dystrophic muscle by Synchrotron deep ultraviolet radiation

Dystrophic muscle is characterized by necrosis/regeneration cycles, inflammation, and fibro-adipogenic development. Conventional histological stainings provide essential topographical data of this remodeling but may be limited to discriminate closely related pathophysiological contexts. They fail to mention microarchitecture changes linked to the nature and spatial distribution of tissue compartment components. We investigated whether label-free tissue autofluorescence revealed by Synchrotron deep ultraviolet (DUV) radiation could serve as an additional tool for monitoring dystrophic muscle remodeling. Using widefield microscopy with specific emission fluorescence filters and microspectroscopy defined by high spectral resolution, we analyzed samples from healthy dogs and two groups of dystrophic dogs: naïve (severely affected) and MuStem cell-transplanted (clinically stabilized) animals. Multivariate statistical analysis and machine learning approaches demonstrated that autofluorescence emitted at 420–480 nm by the Biceps femoris muscle effectively discriminates between healthy, dystrophic, and transplanted dog samples. Microspectroscopy showed that dystrophic dog muscle displays higher and lower autofluorescence due to collagen cross-linking and NADH respectively than that of healthy and transplanted dogs, defining biomarkers to evaluate the impact of cell transplantation. Our findings demonstrate that DUV radiation is a sensitive, label-free method to assess the histopathological status of dystrophic muscle using small amounts of tissue, with potential applications in regenerative medicine.

Phenotypic Detection of Methicillin-Resistant Staphylococcus aureus in Clinical Samples of Dogs and Their Owners in Buwaya, Gonin-gora, Kaduna State, Nigeria

Methicillin-Resistant Staphylococcus aureus (MRSA) are multidrug resistant pathogen of public health concern. It had been reportedly transmitted between individuals and pets in the community. In this study, MRSA was phenotypically detected among dogs and their owners in a small community (Buwaya) in Kaduna state, Nigeria. A total of 63 nasal samples were collected from both dogs and their owners, culture, microscopy and biochemical tests were used to isolate and identify Staphylococcus aureus from the samples. Detection of MRSA isolates was carried out using cefoxitin disc sensitivity testing, a surrogate marker for methicillin resistance. Kirby Bauer disc diffusion method was used for antibiotics testing.The following organisms were isolated: Staphylococcus aureus 13(20.6%), E. coli 14 (22.2%), Coagulase negative Staphylococci 21 (33.3%), Shigella spp 13 (20.6%) and Micrococcus spp 2(3.2%). All the four S. aureus isolates from the dogs were positive for methicillin resistance while 6(66%) of the owners were methicillin resistance positive which showed a total MRSA prevalence of 76.9%. Chloramphenicol (90%) was the most active of all the antibiotics tested followed by cotrimoxazole (80%), doxycycline (70%), ciprofloxacin (70%), gentamicin 60%). The highest level of resistance of the phenotypic MRSA isolates was observed to penicillin (100%), amoxicillin-clavulanic acid (100%) and tetracycline (30%). In conclusion an alarming phenotypic MRSA prevalence of 76.9% was observed among dogs and their owners, the possibility of transmission of MRSA strains between pets and humans was also observed.

Prevalence and genotyping of Cryptosporidium spp. and Giardia lamblia in dogs and cats from a pet hospital in Shanghai Municipality

To investigate the prevalence and genotypes of Cryptosporidium spp. and Giardia lamblia in dogs and cats from a pet hospital in Shanghai Municipality. A total of 145 fresh fecal samples were collected from pet dogs and cats in a pet hospital in Shanghai Municipality during the period from November 2021 to June 2022, including 99 dog fecal samples and 46 cat fecal samples. The small subunit ribosomal ribonucleic acid (SSU rRNA) gene of Cryptosporidium and the triose phosphate isomerase (TPI) gene of G. lamblia were amplified using nested PCR assay, and the positive amplification products were sequenced from both directions. The sequence assembly was performed using the software Clustal X 2.1, and sequence alignment was conducted using BLAST. A phylogenetic tree was created with the Neighbor-Joining method using MEGA 11.0 to identify parasite species or genotype. The overall prevalence of Cryptosporidium and G. lamblia was 20.00% (29/145) in 145 pet dog and cat fecal samples, with the prevalence of 0.69% (1/145) and 19.31% (28/145) in Cryptosporidium and G. lamblia, respectively. G. lamblia was only detected in dog fecal samples, with prevalence of 18.18% (18/99), while the detection rates of Cryptosporidium and G. lamblia were 2.17% (1/46) and 21.74% (10/46) in cat fecal samples. Nucleotide sequence analysis showed that one Cryptosporidium positive sample was characterized as C. felis, and 28 G. lamblia positive samples were all characterized as Giardia assemblage A, which showed 100% sequence homology with human isolates of Giardia. Phylogenetic analysis revealed that the sequences obtained in this study belonged to the same branch with the reported Giardia assemblage A. Cryptosporidium and G. lamblia infection was prevalent in pet dogs and cats from the study pet hospital in Shanghai Municipality, and there is a zoonotic risk for the species and genotype. Intensified surveillance of Cryptosporidium and Giardia infection is recommended in pets and their owners, and improved management of pet keeping is required.

Frequency of dermatophytes and yeasts on tegument of healthy dogs and cats

Skin is an organ that covers the body and acts as a protective layer against external aggressions. Changes in this organ, such as hair loss, evident blemishes, changes in skin pigmentation, and the presence of scaling or crusts, are the main signs of dermatological disease. The study aimed to verify the frequency of dermatophytes and yeasts in healthy cats and dogs. Samples of hair and shedding from 30 cats and 30 dogs were cultured on dermatophyte test medium and Sabouraud Dextrose agar enriched with yeast extract, thiamine, antibiotics (streptomycin and chloramphenicol) supplemented with cycloheximide and incubated at 25°C and 35°C for 10 days. The positive cultures were assessed macro and microscopically, and the fungi were identified by biochemical methods. It was found that 100% of the cats had a positive mycological culture for Microsporum canis, 33.33% for Microsporum gypseum, and 50% for Trichophyton mentagrophytes, with a prevalence of Microsporum canis (P>0.001). In dogs, 86.66% were positive for Microsporum canis, showing a predominance over the other fungal species (P<0.001). Malassezia pachydermatis was isolated in 50% of the dogs evaluated, although it was not found in cats, while positive cultures for Malassezia spp were found in 6.6% of cats and 26.66% of dogs. Candida albicans was isolated in samples of dogs and cats (26.66% and 33.33%, respectively). It was concluded that asymptomatic dogs and cats are carriers of agents of dermatophytosis and dermatomycoses and may be important sources of environmental spread and intra and interspecific infection.

When wildlife comes to town: interaction of sylvatic and domestic host animals in transmission of Echinococcus spp. in Namibia.

The present study was conducted in the isolated desert town of Oranjemund in the far south of Namibia. It is an extremely arid region where no livestock husbandry is practiced and only animals adapted to the desert can be found. However, in and around the city, artificial irrigation maintains lush green patches of grass that attract wild animals, in particular oryx antelopes (Oryx gazella). In 2015 four oryx antelopes were euthanised due to poor conditions and a post-mortem examination was conducted. Two were found positive for cystic echinococcosis and 16 cysts were collected for molecular analyses. In addition, faecal samples from black-backed jackals (n=5) and domestic dogs (n=9), which were regularly observed to feed on oryx carcasses, were collected and taeniid eggs isolated. Parasite species identification of the cysts and eggs was done by amplifying and sequencing the mitochondrial nad1 gene. Both oryx antelopes were found infected with E. ortleppi and one co-infected with E. canadensis G6/7. Both Echinococcus species were able to develop fertile cysts in oryx, making oryx antelopes competent hosts for these parasites. Therefore, the analysis of faecal samples was of high interest and although the numbers were quite small, taeniid eggs were found in three out of five faecal samples of jackals and in all nine dog samples. However, species determination was only successful with two jackal and one dog sample. All three were positive for E. canadensis G6/7. The absence of E. ortleppi may be due to the low number of faecal samples examined. In our small study, we discovered a rather unique lifecycle of Echinococcus spp. between jackals and domestic dogs as definitive hosts and oryx antelopes as intermediate hosts. Here, the presence of E. canadensis G6/7 is of particular concern, as it is the second most important causative agent of CE in humans.

A Robust Test System for DNA Identification of Raccoon Dogs

To establish a system for DNA identification of biological samples of the raccoon dog (Nyctereutes procyonoides), we carried out a study of polymorphism of 39 microsatellite loci and three sex loci specific to various species of the Canidae family. This resulted in the development of the NPlex test system, which includes 14 autosomal STRs and two sex loci. The test system has been validated for use in forensic identification of racoon dogs based on biological traces (such as traces of blood and secretions, fragments of muscle tissue or bones, dermis and hair, etc.) found at crime scenes, as well as for establishing biological relationship of animals of this species. Validation efforts were performed in accordance with the protocol of the Scientific Working Group on DNA Analysis Methods.

Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment.

Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment. Cats and dogs with contemporaneous urine dipstick, microscopic sediment analysis and microbiological culture and sensitivity results over a four-year period (2016 to 2020) were retrospectively identified. Dogs and cats with active urine sediments (at least five erythrocytes and/or five leukocytes per high-power field) and/or spermaturia were excluded. Association between urine pH, haem dipstick result, protein dipstick result and urine protein:creatinine ratio with bacteriuria were evaluated using binary logistic regression analysis. Likelihood ratios for bacteriuria were calculated at different diagnostic thresholds. A total of 668 and 169 dog and cat urine samples were included. Of these, 166 dogs (25%) had a positive urine culture, whilst only 29 cats (17%) had a positive urine culture. In dogs and cats, any positive haem dipstick result was significantly associated with bacteriuria, although only a ≥4+ haem positive result in dogs was associated with a small increase in the likelihood of a positive urine culture, and positive likelihood ratios did not support the use of haem dipstick results as a screening test for bacteriuria in cats. pH, urine protein:creatinine ratio and protein dipstick results were not associated with bacteriuria. Our findings provide proof of concept that haem dipstick pad results in dogs with inactive sediment and without spermaturia might be useful as a screening test for bacteriuria, although further studies are required to confirm these findings.

Molecular detection and species identification of dermatophytes by SYBR-Green real-time PCR in house methodology using hair samples obtained from dogs and cats.

The classical dermatophytes diagnosis is based on mycological culture and microscopy observation both human and animal hair, skin and nail samples. The aim of this work was to develop the new in-house real-time PCR with pan-dematophyte reaction for detection and identification of the main dermatophytes directly from hair samples, providing a simple and rapid diagnosis of dermatophytosis in dogs and cats. An in house SYBR-Green real-time PCR was designed and used for detecting a DNA fragment encoding chitin synthase 1 (CHS1). A total of 287 samples were processed by culture, microscopic examination with KOH 10% and quantitative PCR (qPCR) analysis. Melting curve analysis of CHS1 fragment revealed to be reproducible, showing a single distinct peak for each species of dermatophyte, namely Trichophyton mentagrophytes, Trichophyton verrucosum Microsporum canis and Nannizzia gypsea (formerly Microsporum gypseum). Then, out of the 287 clinically suspected cases of dermatophytosis, 50% were positive for dermatophytes by qPCR, 44% by mycological culture and 25% by microscopic examination. M. canis was identified in 117 samples tested by culture and 134 samples tested by qPCR, followed by N. gypsea in 5 samples (either tested by culture or qPCR) and T. mentagrophytes detected in 4 and 5 samples when tested by culture or qPCR, respectively. Overall, qPCR allowed the diagnosis of dermatophytosis in clinical samples. The results suggest this newly proposed in house real-time PCR assay can be used as alternative diagnosis and rapid identification of dermatophytes frequently associated to clinical hair samples of dogs and cats.

Detection of G3 human-like rotavirus in institutionalized dogs from Brazil.

Viral gastroenteritis is a common clinical problem in dogs and group A rotavirus (RVA) is one of the agents involved in this etiology. It mainly affects dogs in the first 6months of life, and these animals are considered an important reservoir and potential transmitters of the virus to other susceptible hosts, such as humans. Among the different types of RVA, G3 is the most detected in dogs, and this genotype is also involved in infections in other animals, including humans. Thus, the present study aims to investigate the presence of RVA in samples of dogs from a public kennel. A total of 64 fecal samples from dogs with diarrhea were analyzed, collected from April 2019 to March 2020, from the kennel of the Zoonosis Control Center, located in Belém, a city in the North of Brazil. The extracted genetic material was subjected to reverse transcription followed by real-time PCR (RT-qPCR); the positives were tested by RT-PCR with a specific primer for the RVA VP7 gene, after nucleotide sequencing and phylogenetic analysis. One sample was subjected to high-performance sequencing. A positivity of 7.8% (5/64) was observed for RVA, all characterized as G3, grouping in the G3-III lineage, with greater similarity to human samples. Different regions of the RVA genome fragments were found. These results emphasize the need for animal health surveillance to better understand the global strain dispersion of RVA and elucidate possible interspecies transmission events, monitoring the genetic diversity of this pathogen.

Characterization of the pathogenicity of extraintestinal pathogenic Escherichia coli isolates from pneumonia-infected lung samples of dogs and cats in South Korea

This study aimed to investigate the pathogenicity of extraintestinal pathogenic Escherichia coli (ExPEC) isolated from dog and cat lung samples in South Korea. A total of 101 E. coli isolates were analyzed for virulence factors, phylogroups, and O-serogroups, and their correlation with bacterial pneumonia-induced mortality was elucidated. P fimbriae structural subunit (papA), hemolysin D (hlyD), and cytotoxic necrotizing factor 1 (cnf1) were highly prevalent in both species, indicating correlation with bacterial pneumonia. Phylogroups B1 and B2 were the most prevalent phylogroups (36.6% and 32.7%, respectively) and associated with high bacterial pneumonia-induced mortality rates. Isolates from both species belonging to phylogroup B2 showed high frequency of papA, hlyD, and cnf1. O-serogrouping revealed 21 and 15 serogroups in dogs and cats, respectively. In dogs, O88 was the most prevalent serogroup (n = 8), and the frequency of virulence factors was high for O4 and O6. In cats, O4 was the most prevalent serogroup (n = 6), and the frequency of virulence factors was high for O4 and O6. O4 and O6 serogroups were mainly grouped under phylogroup B2 and associated with high bacterial pneumonia-induced mortality. This study characterized the pathogenicity of ExPEC and described the probability of ExPEC pneumonia-induced mortality.

The impact ofurine storage methods onthe results ofquantitative bacterial culture indog and cat.

Quantitative bacterial culture (QBC) isthe gold standard for determining urinary tract infections. However, the majority ofurine samples were sent toalab for further bacterial culture. Therefore, the storage condition was vital tomaintain the quality and accuracy ofthe urine samples. The main objective ofour study was toexamine the urine QBC outcomes of(1) immediate culture, (2) culture after urine sample storage atambient temperature for 24 h, and (3) culture after urine sample storage at4°C for 24hours. There were 49 feline samples and 30 canine samples included inthis study. All QBC samples kept atambient temperature and refrigerator were consistent with immediate QBC incats. Eight positive results from immediate QBC were inaccordance with refrigerated results indogs. There were ten positive results inthe room-temperature sample with two false-positive results. Our study showed that storing conditions atroom temperature orrefrigeration for 24 h does not impact the results ofQBC incat urine samples. For dog samples, chilled samples have ahigher accuracy rate than room temperature samples, although the overall agreement was still satisfactory.

Low Seroprevalence of WNV in Namibian Dogs Suggests a Limited Effectiveness as Sentinels for Infection Monitoring.

West Nile virus (WNV) is an important zoonotic Flavivirus responsible for mild fever to severe neurological disease in humans and horses. Despite the occurrence of major previous outbreaks in Namibia and the likelihood of the current endemicity of the virus, only limited investigations and monitoring activities of WNV have been performed in the country. The use of animal sentinels is a valuable approach toward investigating the infection presence in an area and to predict the potential occurrence of human outbreaks. Serological investigations in dogs hold several advantages, considering their infection susceptibility, the ease of sample handling, and the evaluation of risk factors of pet owners that share the same habit with their pets. To evaluate the usefulness of such a sero-epidemiological investigation in Namibia, a broad serosurvey was performed in 2022 that included 426 archived domestic dog samples from eight Namibian regions. Although the ELISA prevalence, indicative of Flavivirus infection, was relatively high (16.43%; 95 CI: 13.10-20.39%), the virus neutralization test confirmed only a minority of cases, highlighting a prevalence of 2.82% (95 CI: 1.47-4.90%), significantly lower than in Namibian donkeys and reports from other countries. Variables that could explain the recorded differences remain to be explored, including animal exposure, variable vector presence, distribution, and feeding preferences. The study results suggest the limited usefulness of dogs as sentinels for WNV monitoring in Namibia.

Nasal microbiota profiles in shelter dogs with dermatological conditions carrying methicillin-resistant and methicillin-sensitive Staphylococcus species

Dermatological conditions may be complicated by Staphylococcus spp. infections influencing skin and nasal microbiota. We investigated the associations between the resident nasal microbiota of shelter dogs with and without dermatological conditions carrying methicillin-resistant and -sensitive Staphylococcus spp. Nasal sampling of 16 dogs with and 52 without dermatological conditions were performed upon shelter admission (baseline), and then bi-weekly until discharge (follow-up). All samples were cultured for Staphylococcus spp., while 52 samples underwent microbiota analysis. Two elastic net logistic regression (ENR) models (Model 1—baseline samples; Model 2—follow-up samples) were developed to identify predictive associations between dermatological conditions and the variables: signalment, antimicrobial treatment, and nasal microbial genera. Follow-up nasal samples of dogs with dermatological conditions had decreased microbiota diversity and abundance compared to dogs without dermatological conditions. Our ENR models identified predictive differences in signalment and nasal microbial genera between baseline and follow-up samples. Co-occurrence networks showed nasal microbial genera were more dissimilar when comparing dogs with and without dermatological conditions at follow-up. Overall, this study is the first to investigate Staphylococcus spp. carriage effects on nasal microbial genera in a canine animal shelter population, and ultimately reveals the importance of investigating decolonisation and probiotic therapies for restoring nasal microbiota.

Detection of Selected Canine Viruses in Nigerian Free-Ranging Dogs Traded for Meat Consumption.

Animal trade favors the spreading of emerging and re-emerging pathogens. Concerns have been previously expressed regarding the risks of dog trade in spreading zoonotic pathogens in Nigeria. However, the role of these dogs in disseminating highly pathogenic canine viruses has not yet been explored. The present study aimed to identify selected canine viruses in dogs traded for meat consumption in Nigeria. A total of 100 blood samples were screened for carnivore protoparvovirus-1 (CPPV-1), canine adenovirus 1/2 (CAdV-1/2), canine circovirus (CaCV), and canine distemper virus (CDV) by using real-time PCR and conventional PCR and/or sequencing. CPPV-1 DNA was identified in 83% of canine samples while CaCV DNA and CDV RNA were detected in 14% and 17% of the dog samples, respectively. None of the dogs tested positive for CAdV-1/2. The CaCVs identified in this study clustered along with other European, Asian, and American strains. Moreover, CDV strains identified in Nigeria clustered in a separate lineage with the closest genetic relatedness to the Europe-South America-1 clade. Further surveys prior to and after arrival of dogs at the slaughtering points are required to clarify the real virus burden in these animals.

Development and Evaluation of Recombinase Polymerase Amplification Assay for Diagnosis of Canine Leptospirosis

Background: Canine Leptospirosis is a life-threatening disease and zoonosis. Usually, PCR assay is carried out for early diagnosis but requires a thermal cycler and post-PCR procedures. This limits its use in resource-limited areas. Hence, the isothermal amplification of nucleic acid by recombinase polymerase amplification assay was developed as a versatile alternative for the diagnosis of canine leptospirosis in this study. Methods: The RPA assay to detect Leptospira DNA was optimized with Leptospira reference strains and its performance characteristics such as analytical, diagnostics and reproducibility were assessed. Result: The limit of detection of RPA assay was estimated as 102 copies of genomic DNA and specific to amplify the pathogenic Leptospira. Out of 150 dog samples screened, Leptospira DNA was detected in 64 (42.6%) by RPA assay and 67 (44.6%) by PCR. The diagnostic sensitivity and specificity of the RPA assay were 92.5% and 97.59% respectively. The RPA assay has a good diagnostic agreement with a kappa value of 0.905. The reproducibility assessment with the third-party testing laboratory revealed a better agreement with a kappa value of 0.81. The simplicity, rapid and less expensive enable this assay to perform at resource-limited laboratories or point-of-care testing.

Molecular and immunological diagnosis of cystic echinococcosis from different hosts in the Gaza Strip, Palestine

The aim of the present study was to determine the molecular characteristics of Echinococcus granulosus sensu lato from faecal samples of dogs and the hydatid cyst from liver of bovine, camel, cattle, and sheep and the immunodiagnosis of Hydatid cyst in human sera samples from the Gaza Strip, in Palestine. A total of 38 faecal samples were collected near farms and local markets where stray dogs were grouping there. Post-slaughtering, the livers of the bovine, camel, cattle, and sheep were examined for cysts. Where 30 suspected hydatid cysts were collected, the number and size of cysts in each liver were recorded. For serology, 23 sera specimens were collected from farmers within the Gaza Strip. According to hospital records in Gaza, 12 patients had attended three different hospitals and had tested positive for hydatid cyst/cystic echinococcosis by CT scans and histopathology. ELISA results from the 23 human patients showed that 3/23 (13%) tested positive for hydatid disease. Of the 30 bovine and cattle harboring cysts, 14/30 (46.6%) were positive for hydatid cyst/cystic echinococcosis of which 23 (76.7%) were males and 7 (23.3%) were females. The present study shows that 6/38 (15.7%) were positive for E. granulosus sensu lato from faecal analysis in dogs. Subsequent sequencing of both dogs and cattle confirmed infection by the G1 strain. The cattle/dog strain (G1) of E.granulosus sensu lato suggests that this infection is cosmopolitan in its distribution. It is concluded that the detection of hydatid cyst/cystic echinococcosis in the examined hosts either human or animals should be considered among physicians and a large sample size is recommended in future research.

The first dog-origin porcine circovirus type 4 complete genomic sequence have high homology with that of pig-derived strains.

Introduction: Porcine circovirus 4 (PCV4) was discovered in 2019 and then proved to be pathogenic to piglets. Nevertheless, few studies were currently available about PCV4 infection in species other than pigs and there is no information about the prevalence of PCV4 in dogs. Methods: To fill this gap, 264 dog samples were collected from animal hospitals in the Southwest of China from 2021 to 2022 and screened for PCV4. Moreover, the complete genome of one PCV4 strain (SCABTC-Dog2022) were obtained successfully and shared a high identity (97.9-99.0%) with other PCV4 strains derived from pigs, dairy cows, raccoon dogs and foxes. The SCABTC-Dog2022 were analyzed together with 51 reference sequences. Results and Discussion: The detected results showed a low percentage of PCV-4 DNA (1.14%, 3/264), indicating that PCV4 could be identified in dogs in southwest China. Phylogenetic tree showed that SCABTC-Dog2022 strain derived from dog were clustered in a closed relative and geographically coherent branch with other PCV4 strains collected from four provinces (Sichuan, Fujian, Hunan and Inner Mongolia) of China. To our knowledge, it is the first detection of PCV4 in dogs globally. The association between PCV4 status and clinical syndromes in dogs deserves additional investigations.

Executive Functions as Measured by the Dog Executive Function Scale (DEFS) over the Lifespan of Dogs.

Executive Functions (EFs) are needed for effortful self-regulation of behaviour and are known to change over the lifespan in humans. In domestic dogs, EFs can be assessed through behavioural rating scales, such as the Dog Executive Function Scale (DEFS). The primary aim of this study was to investigate whether the DEFS, developed initially using a sample of adult dogs, can be used in juvenile (<1 year) and senior (>8 years) dogs. Confirmatory factor analysis of a juvenile and senior dog sample led to good model fit indices, indicating that juvenile and senior dogs' EF structure follows the same functional organisation as found in the DEFS. The secondary aim was to analyse the lifespan development of EFs. Analysis of subscale scores revealed multifaceted relationships with age for four subscales. Working Memory and Attention Towards Owner showed the u-shaped curve traditionally associated with the lifespan development of EFs. Forms of inhibition showed complex associations with age, i.e., Delay Inhibition declined in aging and Motor Regulation increased during aging. Training history and Working Status influenced performance independent of age. More highly trained dogs and working dogs exhibited higher EF skills. Training history appeared more important for EF in non-working dogs than working dogs, perhaps because all working dogs receive a high level of training.

Unwilling or unable? Using three-dimensional tracking to evaluate dogs' reactions to differing human intentions.

The extent to which dogs (Canis familiaris) as a domesticated species understand human intentions is still a matter of debate. The unwilling-unable paradigm has been developed to examine whether nonhuman animals are sensitive to intentions underlying human actions. In this paradigm, subjects tended to wait longer in the testing area when presented with a human that appeared willing but unable to transfer food to them compared to an unwilling (teasing) human. In the present study, we conducted the unwilling-unable paradigm with dogs using a detailed behavioural analysis based on machine-learning driven three-dimensional tracking. Throughout two preregistered experiments, we found evidence, in line with our prediction, that dogs reacted more impatiently to actions signalling unwillingness to transfer food rather than inability. These differences were consistent through two different samples of pet dogs (total n = 96) and they were evident also in the machine-learning generated three-dimensional tracking data. Our results therefore provide robust evidence that dogs distinguish between similar actions (leading to the same outcome) associated with different intentions. However, their reactions did not lead to any measurable preference for one experimenter over the other in a subsequent transfer phase. We discuss different cognitive mechanisms that might underlie dogs' performance in this paradigm.