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Simple Summary: Enteric viruses are the main cause of gastrointestinal disease in dogs. Canine astrovirus (CaAstV) is an enteric virus that causes severe dehydration, diarrhea and vomiting, among other gastrointestinal symptoms. The present study is based on the design, standardization, and execution of a rapid and sensitive qPCR protocol using SYBR Green for the identification of CaAstV in dogs with gastroenteritis in Ecuador as a causative agent of gastrointestinal disease in co-infection with other viruses, such as canine parvovirus. The assay was shown to be repeatable, specific and sensitive based on the tests performed. The method was tested on 221 samples from dogs with gastroenteritis, of which 52.8% showed positivity for CaAstV. Sequencing of a segment of the ORF1b gene of the virus genome was performed to validate the presence of the virus, leading to the identification of two possible lineages of the virus circulating in Ecuador. This is the first report of CaAstV in the country. The present trial demonstrates the need for the application of molecular methods for the diagnosis and monitoring of emerging viruses in animals that could be influencing canine mortality due to gastrointestinal disease. Enteric viruses are responsible for a significant number of gastrointestinal illnesses in dogs globally. One of the main enteric viruses is the canine astrovirus (CaAstV), which causes diarrhea in dogs of various ages. It is linked to symptoms such as diarrhea, vomiting, depression and a significant mortality rate due to gastrointestinal disorders. It is a single-stranded positive RNA virus, with three open reading frames, ORF1a, ORF1b and ORF2, where the last one codes for the virus capsid protein and is the most variable and antigenic region of the virus. The aim of this work is to develop and standardize a quick detection method to enable the diagnosis of this etiological agent in dogs with gastroenteritis in Ecuador in order to provide prompt and suitable treatment. The assay was specific for amplification of the genome of CaAstV, as no amplification was shown for other canine enteric viruses (CPV-2, CCoV and CDV), sensitive by being able to detect up to one copy of viral genetic material, and repeatable with inter- and intra-assay coefficients of variation of less than 10% between assays. The standard curve showed an efficiency of 103.9%. For the validation of this method, 221 fecal samples from dogs affected with gastroenteritis of various ages from different provinces of Ecuador were used. From the RT-qPCR protocol, 119 samples were found positive for CaAstV, equivalent to 53.8% of the samples processed. CaAstV was detected in dogs where both the highest virus prevalence in the tested strains and the highest viral loads were seen in the younger canine groups up to 48 weeks; in addition, different strains of the virus were identified based on a sequenced fragment of ORF1b, demonstrating the first report of the presence of CaAstV circulating in the domestic canine population affected by gastroenteritis in Ecuador, which could be associated with the etiology and severity of enteric disease. [ABSTRACT FROM AUTHOR]

Enteric viruses are responsible for a significant number of gastrointestinal illnesses in dogs globally. One of the main enteric viruses is the canine astrovirus (CaAstV), which causes diarrhea in dogs of various ages. It is linked to symptoms such as diarrhea, vomiting, depression and a significant mortality rate due to gastrointestinal disorders. It is a single-stranded positive RNA virus, with three open reading frames, ORF1a, ORF1b and ORF2, where the last one codes for the virus capsid protein and is the most variable and antigenic region of the virus. The aim of this work is to develop and standardize a quick detection method to enable the diagnosis of this etiological agent in dogs with gastroenteritis in Ecuador in order to provide prompt and suitable treatment. The assay was specific for amplification of the genome of CaAstV, as no amplification was shown for other canine enteric viruses (CPV-2, CCoV and CDV), sensitive by being able to detect up to one copy of viral genetic material, and repeatable with inter- and intra-assay coefficients of variation of less than 10% between assays. The standard curve showed an efficiency of 103.9%. For the validation of this method, 221 fecal samples from dogs affected with gastroenteritis of various ages from different provinces of Ecuador were used. From the RT-qPCR protocol, 119 samples were found positive for CaAstV, equivalent to 53.8% of the samples processed. CaAstV was detected in dogs where both the highest virus prevalence in the tested strains and the highest viral loads were seen in the younger canine groups up to 48 weeks; in addition, different strains of the virus were identified based on a sequenced fragment of ORF1b, demonstrating the first report of the presence of CaAstV circulating in the domestic canine population affected by gastroenteritis in Ecuador, which could be associated with the etiology and severity of enteric disease.

The role of canine astrovirus (CaAstV) in canine gastrointestinal disease (GID) is unknown. In this study, a total of 327 fecal swab (FS) samples were collected, including 113 FSs in Vietnam (46 samples from healthy dogs and 67 samples from GID dogs) and 214 FSs in Thailand (107 samples from healthy dogs and 107 samples from GID dogs). Overall, the prevalence of CaAstV in Vietnam and Thailand was 25.7% (29/113) and 8.9% (19/214), respectively. CaAstV was detected in both non-diarrhea dogs (21.7 and 7.5%) and diarrhea dogs (28.4% and 10.3%), respectively, in Vietnam and Thailand. In both countries, CaAstV was frequently detected in puppies under 6 months of age (23.3%) (p = 0.02). CaAstV-positive samples in Vietnam and Thailand were identified as co-infected with canine parvovirus, canine enteric coronavirus, canine distemper virus, and canine kobuvirus. The complete coding sequence of seven Vietnamese CaAstV and two Thai CaAstV strains were successfully characterized. Phylogenetic analyses showed that Vietnamese and Thai CaAstV strains were genetically close to each other and related to the Chinese strains. Furthermore, analysis of complete coding sequences indicated that the OR220030_G21/Thailand/2021 strain formed a unique lineage, whereas no recombination event was found in this study, suggesting that this strain might be an original lineage. In summary, this is the first study to report the presence of CaAstV in dogs with and without diarrhea in Vietnam and Thailand, and it was most often found in puppies with diarrhea. Our results highlight the importance of the CaAstV in dog populations and the need for continued surveillance of these emerging pathogens.

In this study, the aetiological background of an outbreak of severe haemorrhagic gastroenteritis (HGE) in a colony of purebred Jack Russell Terriers vaccinated against CPV-2 in Hungary was investigated. Canine parvovirus 2 (CPV-2, Parvoviridae) and canine astrovirus (CaAstV, Astroviridae) co-infection was identified by viral metagenomics and next-generation sequencing (VM-NGS) methods from a rectal swab of an affected 7-week-old puppy. The complete coding sequence of CPV-2 strain FR1/CPV2-2021-HUN (ON733252) and the complete genome of CaAstV strain FR1/CaAstV-2021-HUN (ON733251) were determined by VM-NGS and PCR methods. Results of sequence and phylogenetic analyses showed that CPV-2 strain FR1/CPV2-2021-HUN was different from the applied vaccine strains and previously identified strains from Hungary but showed high sequence identity (> 99.8%) and close phylogenetic relationship to recently described "Asian-origin" CPV-2c strains from Italy. But, based on the single amino acid difference on position 426 of VP2 (Glu/Asp) between the study strain and the closest relatives, FR1/CPV2-2021-HUN belonged to the 2b antigenic type rather than 2c. The CaAstV strain FR1/CaAstV-2021-HUN showed close relationship with a CaAstV strain identified previously from a diarrhoeic dog in Hungary. Both viruses were continuously detectable by PCR in additional enteric samples, and the CPV-2 could also be detected in several (n = 32) tissue samples from 9 affected deceased puppies. Further comparative studies are necessary to confirm the role of the point mutation causing the change in the antigenic type of this "Asian-origin" CPV-2 and/or the role of CaAstV co-infection in the development and/or severity of (haemorrhagic) gastroenteritis among dogs vaccinated against CPV-2. [ABSTRACT FROM AUTHOR]

Gastrointestinal disorders caused by enteric viruses are frequently reported in dogs worldwide, with significant mortality rates in unvaccinated individuals. This study reports the identification and molecular characterization of Canine parvovirus (CPV-2), Canine coronavirus (CcoV), Canine astrovirus (AstV), and Canine calicivirus (CcaV) in a panel of dogs showing severe enteric clinical signs sampled in a typical Mediterranean environment (Sardinia, Italy). At least one of these viral species was detected in 92.3% samples. CPV-2 was the most frequently detected virus (87.2%), followed by AsTv (20.5%), CCoV-IIa (18%), and CCoV-I (10.3%). CCoV-IIb and CaCV were not detected in any sample. Single infection was detected in 24 samples (66.7%), mainly related to CPV-2 (91.7%). Coinfections were present in 33.3% samples with constant detection of CPV-2. Canine coronavirus was present only in coinfected animals. The VP2 sequence analysis of CPV-2 positive samples confirmed the presence of all variants, with CPV-2b most frequently detected. Phylogeny based on the CcoV-IIa spike protein (S) gene allowed to identify 2 different clades among Sardinian isolates but failed to distinguish enteric from pantropic viruses. Study on presence and prevalence of enteroviruses in dogs increase our knowledge about the circulation of these pathogens in the Mediterranean area and highlight the need for dedicated routine vaccine prophylaxis. Molecular analyses of enteric viruses are fundamental to avoid failure of vaccines caused by frequent mutations observed in these enteroviruses. [ABSTRACT FROM AUTHOR]

Astroviruses (AstVs) are major causative agents of gastroenteritis in children and have been reported in many species. Canine astrovirus (CaAstV), as an enteric pathogen, has been widely detected worldwide, but little is known about their genetic diversity and evolution, partly owing to a lack of genomic data. Here, we sequenced 12 nearly full‐length CaAstV genomes to address the gap in knowledge. We found 14 (13.2%) and 7 (3.35%) CaAstV‐positive samples from pet dogs with and without diarrhoea, respectively. Co‐infections were with co‐infection with Torque teno canis virus (TTCaV) reported for the first time. Phylogenetic analysis of the ORF2 gene revealed four major lineages. In particular, lineage 4 might have evolved from a recombinant virus from lineage 2 and lineage 3. The strains sequenced here clustered with lineages 2, 3 and 4 in contrast with other Chinese strains identified previously that clustered with lineages 2 and 4. Amino acid sequence alignment within lineage revealed intralineage amino acid diversity and that the type of epidemic strains within lineages changes over time. Three amino acids substitutions located in predicted B‐cell epitopes, which might be involved escape of host immunity. Moreover, frequent inter‐clade ORF2 gene recombinants were identified. The identification of individual recombination events and a recombinant lineage indicated that recombination plays a crucial role in CaAstV genetic evolution and diversity by generating divergent viruses. Moreover, phylogenetic analysis of ORF1b, the most conserved gene of astrovirus, revealed a close relationship between CaAstV and California sea lion astroviruses. Overall, we report detailed information on the genetic evolution and diversity of CaAstV, which indicates that CaAstV may pose challenges for diagnostics and future control strategies. [ABSTRACT FROM AUTHOR]

Abstract Background Astroviruses (AstVs) have been reported to infect and cause gastroenteritis in most animal species. Human AstVs were regarded the causative agent of viral diarrhea in children. In dogs, little is known about the epidemiology and clinical significance of AstV infection. Findings In this study, we collected and tested 253 rectal swabs from pet dogs; of which 64 samples (25.3%) tested positive for AstVs with diarrhea and 15 more samples (5.9%) also was identified as AstVs, however without any clinical signs. Phylogenetic analysis of 39 partial ORF1b sequences from these samples revealed that they are similar to AstVs, which can be subdivided into three lineages. Interestingly, out of the 39 isolates sequenced, 16 isolates are shown to be in the Mamastrovirus 5/canine astrovirus (CAstV) lineage and the remaining 23 isolates displayed higher similarities with known porcine astrovirus (PoAstV) 5 and 2. Further, analysis of 13 capsid sequences from these isolates showed that they are closely clustered with Chinese or Italy CAstV isolates. Conclusions The findings indicate that CAstVs commonly circulate in pet dogs, and our sequencing results have shown the genomic diversity of CAstVs leading to increasing number of clusters.

Highlights • A canine-like astrovirus was identified in a wild canid (Cerdocyon thous). • The astrovirus strain was likely derived from the canine host. • MAstV5 was detected in an extra-intestinal tissue. • MastV5 genome was nearly complete sequenced and characterized. • Possible natural spillover of this virus among wild Canidae species was proposed. Abstract Astroviruses are a common cause of gastroenteritis in children worldwide and can also cause infection in a range of domestic and wild animal species. Canine astrovirus (formally named as Mamastrovirus 5, MAstV5) has been reported worldwide, and its role as an enteric pathogen is still controversial. Herein, we describe the genomic characterization of a MAstV5 (strain crab-eating fox/2016/BRA) identified in a wild canid (Cerdocyon thous) diagnosed with canine distemper virus (CDV) as causa mortis. The nearly complete genome comprised 6579 nt in length and displayed the archetypal organization of astroviruses. The present report is the first evidence of MAstV5 infection in an animal species other than the dog and highlights a possible natural astrovirus spillover between domestic and wild canids. Moreover, these results show the first evidence of extra-intestinal MAstV5, suggesting a virus systemic spread. This work is expected to contribute to a better understanding of the astroviruses biology and their interactions with the wildlife health. [ABSTRACT FROM AUTHOR]

Background: Astroviruses (AstVs) have been reported to infect and cause gastroenteritis in most animal species. Human AstVs were regarded the causative agent of viral diarrhea in children. In dogs, little is known about the epidemiology and clinical significance of AstV infection. Findings: In this study, we collected and tested 253 rectal swabs from pet dogs; of which 64 samples (25.3%) tested positive for AstVs with diarrhea and 15 more samples (5.9%) also was identified as AstVs, however without any clinical signs. Phylogenetic analysis of 39 partial ORF1b sequences from these samples revealed that they are similar to AstVs, which can be subdivided into three lineages. Interestingly, out of the 39 isolates sequenced, 16 isolates are shown to be in the Mamastrovirus 5/canine astrovirus (CAstV) lineage and the remaining 23 isolates displayed higher similarities with known porcine astrovirus (PoAstV) 5 and 2. Further, analysis of 13 capsid sequences from these isolates showed that they are closely clustered with Chinese or Italy CAstV isolates. Conclusions: The findings indicate that CAstVs commonly circulate in pet dogs, and our sequencing results have shown the genomic diversity of CAstVs leading to increasing number of clusters. [ABSTRACT FROM AUTHOR]

The role of canine astrovirus (CaAstV) in canine gastrointestinal disease (GID) is unknown. In this study, a total of 327 fecal swab (FS) samples were collected, including 113 FSs in Vietnam (46 samples from healthy dogs and 67 samples from GID dogs) and 214 FSs in Thailand (107 samples from healthy dogs and 107 samples from GID dogs). Overall, the prevalence of CaAstV in Vietnam and Thailand was 25.7% (29/113) and 8.9% (19/214), respectively. CaAstV was detected in both non-diarrhea dogs (21.7 and 7.5%) and diarrhea dogs (28.4% and 10.3%), respectively, in Vietnam and Thailand. In both countries, CaAstV was frequently detected in puppies under 6 months of age (23.3%) ( p  = 0.02). CaAstV-positive samples in Vietnam and Thailand were identified as co-infected with canine parvovirus, canine enteric coronavirus, canine distemper virus, and canine kobuvirus. The complete coding sequence of seven Vietnamese CaAstV and two Thai CaAstV strains were successfully characterized. Phylogenetic analyses showed that Vietnamese and Thai CaAstV strains were genetically close to each other and related to the Chinese strains. Furthermore, analysis of complete coding sequences indicated that the OR220030_G21/Thailand/2021 strain formed a unique lineage, whereas no recombination event was found in this study, suggesting that this strain might be an original lineage. In summary, this is the first study to report the presence of CaAstV in dogs with and without diarrhea in Vietnam and Thailand, and it was most often found in puppies with diarrhea. Our results highlight the importance of the CaAstV in dog populations and the need for continued surveillance of these emerging pathogens., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Nguyen, Piewbang and Techangamsuwan.)

Canine astrovirus (CAstV) is the causative agent of gastroenteritis in dogs. We collected rectal swabs from dogs with or without diarrhea symptoms in Japan and examined the feces for the presence of CAstV by RT-PCR with primers based on a conserved region of the ORF1b gene. The ORF1b gene of CAstV was not detected in the 42 dogs without clinical illness but was present in three pups out of the 31 dogs with diarrhea symptoms. Based on the full-length capsid protein, the CAstV KU-D4-12 strain that we detected in this study shared high homology with the novel virulent CAstV VM-2011 strain. [ABSTRACT FROM AUTHOR]

Astroviruses are a common cause of gastroenteritis in children worldwide. These viruses can also cause infection in a range of domestic and wild animal species. Canine astrovirus (CaAstV) was first identified in the USA, and has since been reported in dogs from Europe, the Far East and South America. We sought to determine whether CaAstV is circulating in the UK dog population, and to characterise any identified strains. Stool samples were collected from pet dogs in the UK with and without gastroenteritis, and samples were screened for CaAstV by qPCR. Four CaAstV positive samples were identified from dogs with gastroenteritis (4/67, 6.0%), whereas no samples from healthy dogs were positive ( p < 0.001). Sequencing of the capsid sequences from the four CaAstV strains found significant genetic heterogeneity, with only 80% amino acid identity between strains. The full genome sequence of two UK CaAstV strains was then determined, confirming that CaAstV conforms to the classic genome organisation of other astroviruses with ORF1a and ORF1b separated by a frameshift and ORF2 encoding the capsid protein. This is the first report describing the circulation of CaAstV in UK dogs with clinical signs of gastroenteritis, and the first description of the full-length genomes of two CaAstV strains. [ABSTRACT FROM AUTHOR]

• The study establishes a novel assay for detection of canine astrovirus. • The method in this study is highly sensitive, specific, and reliable. • The method is of great significance for the clinical detection of canine astrovirus. In this study, a TaqMan-based real-time polymerase chain reaction (PCR) method to detect canine astrovirus in clinical samples was developed. Primers and probes were designed to target conserved regions of the complete viral genome sequence. The results showed that the proposed method can detect a minimum of 101 copy numbers. No cross-reactivity with other canine and feline viruses was observed. The coefficient of variation was <5%. Evaluation of the clinical samples showed that quantitative PCR had a 5.26 % higher positive detection rate than conventional PCR. These results indicate that the method developed in this study is highly reliable and suitable for veterinary clinical diagnosis and epidemiological investigations. [ABSTRACT FROM AUTHOR]

• A duplex SYBR Green I based real-time PCR assay was established for CaKoV and CaAstV. • Specific primers targeting 3D of CaKoV and Cap of CaAstV were designed. • The assay had high specificity, sensitivity, and reproducibility. A duplex SYBR Green I-based real-time PCR assay was established for the simultaneous detection of canine kobuvirus (CaKoV) and canine astrovirus (CaAstV). This assay can easily distinguish the two viruses according to their different melting temperatures (Tm) of 80 °C for CaKoV and 86.5 °C for CaAstV; other canine enteroviruses used as controls showed no specific melting peaks. The detection limit of this assay was determined to be 101 copies/μL for both viruses. This method exhibited high repeatability and reproducibility, with a coefficient of variation less than 1.5 %. A total of 48 fecal samples were collected for clinical testing by real-time PCR and confirmed by sequencing. Real-time PCR assay showed a 10.4 % CaKoV-positive rate and a 4.2 % CaAstV-positive rate, and the positive rate of co-infection of the two viruses was 2.1 %, which was consistent with the sequencing results. This assay has many advantages over conventional PCR: it is rapid, sensitive, specific, and reliable for detecting these two viruses in one sample, and it can be used as a tool to detect CaKoV and CaAstV infection or co-infection in clinical settings. [ABSTRACT FROM AUTHOR]

The similar clinical characteristics of canine circovirus (CaCV) and canine astrovirus (CaAstV) infections and high frequency of co-infection make diagnosis difficult. In this study, a duplex SYBR Green I-based real-time polymerase chain reaction (PCR) assay was established for the rapid, simultaneous detection of CaCV and CaAstV. Two pairs of specific primers were designed based on the Rep gene of CaCV and the Cap gene of CaAstV. By using the real-time PCR assay method, the two viruses can be distinguished by the difference in melting temperatures, 79 °C and 86 °C for CaCV and CaAstV, respectively. This assay had high specificity, showing no cross-reaction with other common canine viruses, as well as high sensitivity, with minimum detection limits of 9.25 × 101 copies/μL and 6.15 × 101 copies/μL for CaCV and CaAstV, respectively. Based on the mean coefficient of variation, the method had good reproducibility and reliability. In a clinical test of 57 fecal samples, the rates of positive detection by real-time PCR were 14.04% (8/57) and 12.28% (7/57) for CaCV and CaAstV, respectively, and the rate of co-infection was 8.77% (5/57). In conclusion, the newly established duplex SYBR Green I-based real-time PCR assay is sensitive, specific, reliable, and rapid and is an effective tool for the detection of co-infections with CaCV and CaAstV. • A duplex SYBR Green I based real-time PCR assay was established for CaCV and CaAstV. • Specific primers targeting Rep of CaCV and Cap of CaAstV were designed. • The assay had high specificity, sensitivity, and reproducibility. [ABSTRACT FROM AUTHOR]

Background: Canine astrovirus (CAstV) has been considered the primary cause of gastroenteritis in young animals worldwide, while canine vesivirus (CVeV) and canine circovirus (CCiV) are occasionally reported., Aims: This study aimed to investigate the existence and molecular characteristics for these three viruses in Turkey. Methods: Faecal samples from 150 shelter dogs with gastrointestinal problems (127 adults and 23 puppies) were collected and examined by reverse transcription-polymerase chain reaction (RT-PCR) analysis based on the partial sequence of RdRp gene (ORF1b) for CAstV, ORF2 gene of CVeV and capsid protein (Cap) and replication associated protein ( Rep ) gene of CCiV. Randomly selected positive samples were submitted to sequencing and molecular analyses were conducted based on partial sequences., Results: It was found that 66% (99/150) of diarrhoeic dogs were positive for CAstV, 3.33% (5/150) for CVeV, and 6% (9/150) for CCiV. Four sub-genotypes for CAstV and two sub-genotypes for CVeV were suggested according to molecular analyses. The phylogenetic relationship of CCiV with other strains obtained from various areas was further demonstrated., Conclusion: This study emphasizes the importance of emerging viruses for canids, classification of them and their proportional contribution in gastroenteritis cases. We concluded that astrovirus infection must be considered as the major cause of diarrhea in dogs; However, the prevalences of vesivirus and circovirus were relatively low in cases makes them less important in Turkey.

The aim of this study was to investigate canine astrovirus (CaAstV) infection in southwest China. We collected 107 faecal samples from domestic dogs with obvious diarrhoea. Forty-two diarrhoeic samples (39.3 %) were positive for CaAstV by RT-PCR, and 41/42 samples showed co-infection with canine coronavirus (CCoV), canine parvovirus-2 (CPV-2) and canine distemper virus (CDV). Phylogenetic analysis based on 26 CaAstV partial ORF1a and ORF1b sequences revealed that most CaAstV strains showed unique evolutionary features. Interestingly, putative recombination events were observed among four of the five complete ORF2 sequences cloned in this study, and three of the five complete ORF2 sequences formed a single unique group, suggesting that these strains could be a novel genotype. We successfully sequenced the complete genome of one CaAstV strain (designated 2017/44/CHN), which was 6628 nt in length. The features of this genome include putative recombination events in the ORF1a, ORF1b and ORF2 genes, while the ORF2 gene had a continuous insertion of 7 aa in region II compared with the other complete ORF2 sequences available in GenBank. Phylogenetic analysis showed that 2017/44/CHN formed a single group based on genome sequences, suggesting that this strain might be a novel genotype. The results of this study revealed that CaAstV circulates widely in diarrhoeic dogs in southwest China and exhibits unique evolutionary events. To the best of our knowledge, this is the first report of recombination events in CaAstV, and it contributes to further understanding of the genetic evolution of CaAstV.

Mamastrovirus 5 (MAstV5), belonging to the Astroviridae (AstV) family, previously known as canine astrovirus or astrovirus-like particles, has been reported in several countries to be associated with viral enteric disease in dogs since the 1980s. Astroviruses have been detected in fecal samples from a wide variety of mammals and birds that are associated with gastroenteritis and extra enteric manifestations. In the present study, RT-PCR was used to investigate the presence of MAstV5 in 269 dog fecal samples. MAstV5 was detected in 26% (71/269) of the samples. Interestingly, all MAstV5-positive samples derived from dogs displaying clinical signs suggestive of gastroenteritis, other enteric viruses were simultaneously detected (canine parvovirus, canine distemper virus, canine coronavirus, canine adenovirus and canine rotavirus). Based on genomic sequence analysis of MAstV5 a novel classification of the species into four genotypes, MAstV5a-MAstV5d, is proposed. Phylogenetic analyses based on the ORF2 amino acid sequences, samples described herein grouped into the putative genotype 'a' closed related with Chinese samples. Other studies are required to attempt the clinical and antigenic implications of these astrovirus genotypes in dogs., (Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.)