Molecular survey of parvovirus, astrovirus, coronavirus, and calicivirus in symptomatic dogs

Molecular characterization and lineage analysis of canine astrovirus strains from dogs with gastrointestinal disease in Ecuador based on ORF-2 gene analysis

Canine Astrovirus (CaAstV) part of the Astroviridae family and genus Mamastrovirus, is a linear RNA virus with a genome of approximately 6.6 kb with three open reading frames (ORF): ORF1a and ORF1b, which code for the most conserved non-structural proteins, and ORF2, which code for the capsid protein, the most variable region of the genome. This pathogen has been linked to gastrointestinal infections, primarily causing symptoms such as vomiting, diarrhea, lethargy and severe dehydration, mainly in co-infection with other enteric viruses. In the present study, the presence of CaAstV was identified in dogs with gastrointestinal disease in Ecuador using RT-qPCR with hydrolysis probes, these samples have also tested positive for canine parvovirus type 2 (CPV-2) and canine coronavirus (CCoV). Positive samples were used for end-point RT-PCR amplification and sequencing of ORF-2 using Sanger technology. The sequences were subjected to phylogenetic analysis to determine lineages and possible recombination events. Of the 502 samples tested, 336 were found to be positive for CaAstV, 49.4% in co-infection with CPV-2, 1% in co-infection with CCoV, and 4% in simultaneous infection with all three viruses. The presence of 4 of the 5 previously reported CaAstV lineages were identified, and three possible recombinant strains were identified. Given the high frequency of CaAstV infections in dogs with gastroenteritis and its high genetic variability, it emphasizes the need to implement routine diagnostic measures that include this pathogen as one of the main causes of the disease and a risk agent in case of multiple infections.

Introduction of a Divergent Canine Parvovirus Type 2b Strain with a Dog in Sicily, Southern Italy, Through the Mediterranean Sea Route to Europe

Despite over four decades since its emergence, canine parvovirus type 2 (CPV-2) remains a relevant disease for dogs. Few studies, primarily only recent ones based on phylodynamic and phylogeography approaches, have highlighted the impact of rapid and long-distance transport of dogs on the CPV-2 spreading dynamics. The present study reports the genomic characterization of a CPV-2 strain detected in a dog introduced into Italy from the coasts of North Africa through the Mediterranean Sea route to Europe. The nearly complete CPV-2 sequence was obtained and analyzed. The viral isolate was characterized as a CPV-2b variant, showing genetic signatures distinct from those of CPV-2 strains detected to date in Europe. Phylodynamic and phylogeographic approaches revealed a close correlation with CPV-2 strains recently reported in the Middle East (Turkey and Egypt), which likely originated or co-evolved from Asian ones. It is at least suggestive that the inferred spreading pattern overlaps with the routes often followed by migrants travelling from Asia and Middle East to Europe, passing through Africa. This evidence for the introduction of CPV-2 via the Mediterranean Sea route to Europe highlights the relevant role of the dog movements in the global spread of emerging or re-emerging viral pathogens.

Genetic and Evolutionary Analysis of Canine Coronavirus in Guangxi Province, China, for 2021-2024

Canine coronavirus (CCoV) is an important gastrointestinal pathogen that causes serious harm to pet dogs worldwide. Here, 1791 clinical samples were collected from pet dogs in different pet hospitals in Guangxi Province, southern China, for the 2021-2024 period and detected for CCoV by a multiplex RT-qPCR. The results showed that 8.43% (151/1791) of samples were positive for CCoV. Sixty-five positive samples were selected to amplify, sequence, and analyze S, M, and N genes. A sequence comparison revealed that the nucleotide and amino acid similarities of the S, M, and N genes were 94.86% and 94.62%, 96.85% and 97.80%, and 96.85% and 97.80%, respectively. Phylogenetic analysis indicated that 65 CCoV strains obtained in this study belonged to the CCoV-II genotype, of which 56 CCoV strains belonged to the CCoV-IIa subtype and 9 CCoV strains belonged to the CCoV-IIb subtype. A potential recombination event analysis of S gene sequences indicated that two CCoV strains, i.e., GXBSHM0328-34 and GXYLAC0318-35, have recombination signals. A Bayesian analysis indicated that the evolutionary rates of the S, M, and N genes were 1.791 × 10-3, 6.529 × 10-4, and 4.775 × 10-4 substitutions/site/year, respectively. The population size grew slowly before 1980 and then began to shrink slowly; it then shrank rapidly in 2005 and expanded sharply in 2020, leveling off thereafter. These results indicated the CCoV strains prevalent in Guangxi Province, southern China, showed a high level of genetic diversity and maintained continuous variation among clinical epidemic strains.

Analysis of viral diversity in dogs with acute gastroenteritis from Brazilian Amazon

Viral gastroenteritis is commonly reported in dogs and involves a great diversity of enteric viruses. In this research, viral diversity was investigated in dogs with diarrhea in Northern Brazil using shotgun metagenomics. Furthermore, the presence of norovirus (NoV) was investigated in 282 stool/rectal swabs of young/adult dogs with or without diarrhea from two public kennels, based on one-step reverse transcription polymerase chain reaction (RT-PCR) for genogroup VI and VII (GVI and GVII) and real-time RT-PCR for GI, GII, and GIV. Thirty-one viral families were identified, including bacteriophages. Phylogenetic analyses showed twelve complete or nearly complete genomes belonging to the species of Protoparvovirus carnivoran1, Mamastrovirus 5, Aichivirus A2, Alphacoronavirus 1, and Chipapillomavirus 1. This is the first description of the intestinal virome of dogs in Northern Brazil and the first detection of canine norovirus GVII in the country. These results are important for helping to understand the viral groups that circulate in the canine population.

First Report on the Molecular Detection of Canine Astrovirus (CaAstV) in Dogs with Gastrointestinal Disease in Ecuador Using a Fast and Sensitive RT-qPCR Assay Based on SYBR Green®

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.

Epidemiological investigation of enteric canine coronaviruses in domestic dogs: A systematic review and meta-analysis

Canine enteric coronavirus (CeCoV) is a globally distributed enteric pathogen that causes significant harm to canines. The objective of this systematic review was to examine the global dissemination of CeCoV and assess the potential for infected canines to be exposed to various CeCoV genotypes and subtypes. With an aggregated prevalence of 18.8%, the study predicted regional variations, indicating that CeCoV is an exceptionally prevalent disease. The increased likelihood that infected canines will be asymptomatic is a significant cause for concern, as undetected cases of CeCoV infection could persist and spread the disease. This underscores the significance of ongoing surveillance of CeCoV in order to avert its transmission. Nevertheless, further investigation is necessary in order to ascertain the moderators that significantly impact the prevalence and distribution of distinct subtypes and genotypes of CeCoV. Hence, it is imperative to undertake randomized clinical trials in order to acquire a more accurate understanding of the variables that influence the prevalence of CeCoV. By conducting ongoing surveillance, regional variations in the prevalence of CeCoV in canines can be accounted for, thereby enhancing our comprehension of the illness and ultimately impeding its transmission.

Molecular Screening and Characterization of Canine Coronavirus Types I and II Strains from Domestic Dogs in Southern Italy, 2019-2021

Canine coronavirus (CCoV) is a common agent of gastroenteritis in dogs, although some variants have been found associated with systemic and often fatal diseases. Distinct genotypes (CCoV-I and CCoV-II) and subgenotypes (CCoV-IIa and CCoV-IIb) are worldwide distributed. In Italy, CCoV infections have been occasionally evaluated, but information about the molecular epidemiology and the genomic features of currently circulating strains is limited. This study reports the detection and molecular characterization of CCoV strains from samples collected from 284 dogs in Italy between 2019 and 2021. CCoV RNA was detected in 39 (13.7%) dogs, as a single viral agent (5 animals, 12.8%) or with other viral pathogens (canine parvovirus types 2a/2b/2c; canine adenovirus type 1; norovirus GIV.2) (34 animals, 87.2%). A total of 48 CCoV strains were detected either alone (CCoV-I: 51.3%, CCoV-IIa: 20.5%) or in copresence (CCoV-I and CCoV-IIa, 23.1%); surprisingly, CCoV-IIb was not identified in this study. Five clusters of CCoV-I were detected, and their spike gene sequences showed the highest nucleotide identities with CCoV-I strains collected from Greece in 2008/2009 and from China in 2021. CCoV-IIa spike gene sequences (three variants) had the highest nucleotide identities with CCoV-IIa strains collected in Greece in 2008/2009 and in Italy in 2009/2011. Given the high CCoV diversity and the variable pathogenicity potential, we underline the need of further surveillance studies to increase our understanding of the epidemiology and evolution of these viruses.

Molecular epidemiology of canine parvovirus type 2 in Sicily, southern Italy: A geographical island, an epidemiological continuum

Since it emerged as a major dog pathogen, canine parvovirus type 2 (CPV-2) has featured a remarkable genetic and phenotypic heterogeneity, whose biological, epidemiological, and clinical impact is still debated. The continuous monitoring of this pathogen is thus of pivotal importance. In the present study, the molecular epidemiology of CPV-2 in Sicily, southern Italy, has been updated by analysing 215 nearly complete sequences of the capsid protein VP2, obtained from rectal swabs/faeces or tissue samples collected between 2019 and 2022 from 346 dogs with suspected infectious gastrointestinal disease. The presence of the original CPV-2 type (4%) and CPV-2a (9%), CPV-2b (18%), or CPV-2c (69%) variants was documented. Over the years, we observed a decrease in the frequency of CPV-2a/-2b and a rapid increase of CPV-2c frequency, with a progressive replacement of the European lineage of CPV-2c by the Asian lineage. The observed scenario, besides confirming epidemiological relevance of CPV-2, highlights the occurrence of antigenic variant shifts over time, with a trend toward the replacement of CPV-2a, CPV-2b, and the European lineage of CPV-2c by the emerging Asian CPV-2c lineage. The comparison with other Italian and international sequences suggests the occurrence of viral exchange with other Italian regions and different countries, although the directionality of such viral flows could not be often established with confidence. In several instances, potential CPV-2 introductions led to epidemiological dead ends. However, major, long-lasting clades were also identified, supporting successful infection establishment, local spreading, and evolution. These results, besides demonstrating the need for implementing more effective control measures to prevent viral introductions and minimize circulation, stress the relevance of routine monitoring activities as the only tool to effectively understand CPV-2 epidemiology and evolution, and develop adequate countermeasures.

Investigation of circulating infectious agents in experimental Beagle dogs of a production colony and three research facilities in China from June 2021 to May 2022

To understand the epizootiologic characteristics of pathogens and opportunistic infections in one Beagle dog production colony and three research facilities, viruses and mycoplasma were detected in 1777 samples collected from Beagle dogs in China by polymerase chain reaction/reverse transcription polymerase chain reaction, and bacteria were isolated and identified by 16S rRNA sequence analysis. In addition, genotyping of the major circulating viruses was carried out by amplification of gene fragments and homology analysis. Canine coronavirus (CCoV), Escherichia coli, canine parvovirus (CPV), Bordetella bronchiseptica, Clostridium perfringens, Mycoplasma cynos, Klebsiella pneumoniae, Streptococcus canis, canine astrovirus (CaAstV), canine kobuvirus (CaKV), Pseudomonas aeruginosa, Proteus mirabilis, Macrococcus canis, Pasteurella canis, canine bocavirus (CBoV) and canine adenovirus (CAdV) were detected in the samples. Single, double, triple and quadruple infections accounted for 6.6%, 1.4%, 1.2% and 0.96% of samples, respectively. CCoV strains in 81 samples included three genotypes, CCoV-I, CCoV-IIa and CCoV-IIb, by analysis of S gene. The rate of single infection of CCoV-I, CCoV-IIa or CCoV-IIb was 19%, 38% or 7.4% respectively. The double and triple infection rates of CCoV were 32.8% and 2.5% respectively. All CPV strains in 36 samples belonged to CPV-2c. There were three amino acid differences in the Fiber protein of CAdV-positive sample QD2022, compared with the reference strain Toronto A26/61 and the vaccine strain YCA-18. These results suggest that CCoV and CPV are primary infectious agents, and that these two viruses were often identified in mixed infections, or coinfections alongside mycoplasma or other bacteria. These results will provide the basis for improvements in prevention and control of naturally occurring infectious diseases in Beagle dog production colonies and research facilities.

Canine circovirus among dogs and cats in China: first identification in cats

Canine circovirus (CanineCV) is a virus associated with respiratory and digestive diseases in dogs and often occurs in coinfections with other pathogens, thereby aggravating the symptoms of infected dogs. CanineCV was first reported in the United States in 2012. Subsequently, it was reported among dogs in Europe, Asia, and South America. To investigate the prevalence of CanineCV in dogs in China, 331 dog samples were collected in this study. The PCR results showed that 9.06% (30/331, 95% CI = 6.2% ~ 12.7%) of the dog samples were CanineCV positive. CanineCV has also been detected in some carnivorous wild animals, indicating the potential risk of cross-species transmission of this virus. And, cats are also one of the most common pets in our daily lives, who is close contact with dogs. Thus, this study first investigated the prevalence of CanineCV in cats. The PCR results showed that 3.42% (14/409, 95% CI = 1.9% ~ 5.7%) of the cat samples were CanineCV positive. Moreover, 14 canine-derived CanineCV whole genomes and the first cat-derived CanineCV whole genome were obtained in this study. Rep and Cap are the major nonstructural proteins and structural proteins of CanineCV, respectively. In nucleic acid homology analyses, these 15 CanineCV strains showed a high degree of variation in Rep (85.9 ~ 99%) and Cap (85.6 ~ 100%). In phylogenetic analyses, the 15 CanineCV strains clustered into 3 different genotypes (genotypes 1, 3, and 4). Among them, the first cat-derived CanineCV belonged to CanineCV-3. In addition, 4 genetic recombination events were predicted in these 15 CanineCV strains, occurring in multiple regions of the genome. In conclusion, this study is the first to provide evidence of CanineCV infection in cats and successfully obtained the first whole genome of cat-derived CanineCV. The complex circulation and high prevalence of CanineCV among dogs and cats emphasize the importance of continuous monitoring of this virus in various animal species.

A multi-strain probiotic promoted recovery of puppies from gastroenteritis in a randomized, double-blind, placebo-controlled study

Objective and animals

Acute diarrhea is among the most common causes of veterinary consultations for dogs. A double-blind, placebocontrolled intervention trial was done with 120 puppies with gastroenteritis. These dogs were 1 to 4 mo old, male and female, of various breeds and sizes.

Procedure

Dogs were randomly allocated into 2 groups: Those in the treated group (TG) received a multi-strain probiotic with Lactobacillus johnsonii CRL1693, Ligilactobacillus murinus CRL1695, Limosilactobacillus mucosae CRL1696, and Ligilactobacillus salivarius CRL1702 (1 × 109 CFU/mL) daily for 7 d, whereas those in the control group (CG) received a placebo. All puppies received intravenous fluids, an antiparasitic, amoxicillin PO, and enrofloxacin SC.

Results

At the start of the trial, the 2 groups were similar. Probiotic administration for 7 d normalized fecal consistency, with 69, 50, and 80% of small, medium, and large puppies in the TG achieving a fecal score of 1 (separate hard lumps) at 7 d, significantly better than puppies in the CG. After 7 d of treatment, most puppies (70%) in the TG had an excellent recovery, whereas in the CG, recoveries were 35.7% "bad" and 30.4% "fair." Therefore, treatment with probiotics hastened recovery (P < 0.0001). At the end of the trial, there was a significant increase of cultivable lactobacilli in the feces of TG puppies, but no significant differences between the 2 groups in numbers of total mesophylls, enterobacteria, or Gram-positive cocci. Total mortality was 5.8%, including 4 puppies from the CG and 3 from the TG.

Conclusion

In a randomized, double-blind, placebo-controlled study, puppies with gastroenteritis symptoms receiving a multi-strain probiotic had rapid improvement, implying beneficial effects on the microbiota and its functionality.

Detection and genetic characterization of canine kobuvirus from stray dogs in Shanghai, China

In this study, rectal samples collected from 60 stray dogs in dog shelters were screened for canine kobuvirus and other enteroviruses by quantitative real-time reverse transcription polymerase chain reaction. Canine kobuvirus was detected in 25% (15/60) of the samples. In the 15 positive samples, the coinfection rates of canine distemper virus, canine coronavirus, canine astrovirus, canine norovirus, and canine rotavirus were 26.67%, 20.00%, 73.33%, 0%, and 20.00%, respectively. Phylogenetic analysis based on partial VP1 sequences identified a novel canine kobuvirus that was a recombinant of canine and feline kobuvirus. Bayesian evolutionary analysis revealed that the rate of evolution of the VP1 gene of canine kobuvirus was 1.36 × 10^-4 substitutions per site per year (95% highest posterior density interval, 6.28 × 10^-7 - 4.30 × 10^-4 substitutions per site per year). Finally, the divergence time of VP1 was around 19.44 years ago (95% highest posterior density interval, 12.96-27.57 years).

Coagulation Abnormalities in Dogs with Parvoviral Enteritis

Hemostatic alterations have been documented in dogs with canine parvoviral enteritis. This study's aims were to measure the standard coagulation parameters, and to assess the relationship between them and the clinical variables in dogs with canine parvoviral enteritis. Nine client-owned dogs with a canine parvoviral infection were included in a prospective, observational clinical study. Clinical score and coagulation status were assessed at admission. All nine dogs showed alterations of three or more standard coagulation variables. A correlation analysis evidenced a significantly high positive correlation between the activated partial thromboplastin time and clinical score. The present study concurs that dogs with canine parvoviral enteritis have coagulation disorders that are detectable by measuring the standard coagulation parameters.

A comprehensive molecular survey of viral pathogens associated with canine gastroenteritis

Viral pathogens are the primary cause of canine gastroenteritis. However, few structured comprehensive studies on the viral etiology of canine gastroenteritis have been conducted. In this study, 475 rectal swabs collected over three years (2018-2021) from clinical canine gastroenteritis cases were screened for the presence of six major enteric viruses - canine parvovirus 2 (CPV-2), canine distemper virus (CDV), canine adenovirus 2 (CAdV-2), canine coronavirus (CCoV), canine astrovirus (CaAstV), and canine rotavirus (CRV) - by real-time PCR. The most frequently detected virus was CPV-2, which was present in 64.8% of the samples (subtype 2a, 21.1%; 2b, 77.4%; 2c, 1.5%), followed by CDV (8%), CaAstV (7.2%), CCoV (5.9%), and CAdV-2 (4.6%). Two to four of these viruses in different combinations were found in 16.8% of the samples, and CRV was not detected. The complete genome sequences of Indian isolates of CDV, CCoV, and CaAstV were determined for the first time, and phylogenetic analysis was performed. This study highlights the need for routine prophylactic vaccination with the appropriate vaccines. Notably, 70.3% of animals vaccinated with DHPPiL were found to be positive for at least one virus. Hence, regular molecular analysis of the prevalent viruses is crucial for addressing vaccination failures.

Phylogenetic Diversity of Animal Oral and Gastrointestinal Viromes Useful in Surveillance of Zoonoses

Great emphasis has been placed on bacterial microbiomes in human and animal systems. In recent years, advances in metagenomics have allowed for the detection and characterization of more and more native viral particles also residing in these organisms. The digestive tracts of animals and humans—from the oral cavity, to the gut, to fecal excretions—have become one such area of interest. Next-generation sequencing and bioinformatic analyses have uncovered vast phylogenetic virome diversity in companion animals, such as dogs and cats, as well as farm animals and wildlife such as bats. Zoonotic and arthropod-borne illnesses remain major causes of worldwide outbreaks, as demonstrated by the devastating COVID-19 pandemic. This highlights the increasing need to identify and study animal viromes to prevent such disastrous cross-species transmission outbreaks in the coming years. Novel viruses have been uncovered in the viromes of multiple organisms, including birds, bats, cats, and dogs. Although the exact consequences for public health have not yet become clear, many analyses have revealed viromes dominated by RNA viruses, which can be the most problematic to human health, as these genomes are known for their high mutation rates and immune system evasion capabilities. Furthermore, in the wake of worldwide disruption from the COVID-19 pandemic, it is evident that proper surveillance of viral biodiversity is crucial. For instance, gut viral metagenomic analysis in dogs has shown close relationships between the highly abundant canine coronavirus and human coronavirus strains 229E and NL63. Future studies and vigilance could potentially save many lives.

Canine circovirus and Canine adenovirus type 1 and 2 in dogs with parvoviral enteritis

Canine parvovirus type 2 (CPV-2) is one of the most relevant pathogens associated with enteritis in dogs and is frequently reported in association with the detection of other pathogens in faeces. In this study the concomitant presence of Canine circovirus (CanineCV) and Canine adenovirus (CAdV) DNA in faecal or intestine samples of 95 dogs with parvovirus enteritis sampled in Italy (1995–2017) was investigated and the viruses identified were genetically characterised. Potential correlations with the antigenic variant of CPV-2 and with signalment data and outcome were evaluated. Twenty-eight of 95 (29.5%) CPV-2 infected dogs tested positive to other viruses: 7/28 were also positive to CanineCV, 1/28 to CAdV-1, 18/28 to CAdV-2, 1/28 to CanineCV and CAdV-2, and 1/28 to CAdV-1 and CAdV-2. The frequency of CAdV DNA detection and coinfections was significantly higher in purebred dogs compared to mixed breed ones (P = 0.002 and 0.009, respectively). The presence of coinfection was not associated with any other relevant data available, including CPV-2 variant and final outcome. The detection of CanineCV in a dog sampled in 2009 allowed to backdating its circulation in dogs. The eight CanineCV completely sequenced were phylogenetically related to the CanineCV identified in dogs, wolves and a badger from Europe, USA, Argentina and China. Nine CAdV were partially sequenced and phylogenetic analysis showed a separate branch for the oldest CAdV-2 identified (1995). From the results obtained in this study population, CanineCV and CAdV coinfections in dogs with parvoviral enteritis did not result in more severe disease.