Characterization of canine coronavirus spread among domestic dogs in Vietnam

Genetic diversity of canine coronavirus identified in dogs in yulin city, southern China

The global outbreak of the novel coronavirus has renewed interest in related viral pathogens, including canine coronavirus (CCoV), which causes severe gastroenteritis, diarrhea, and vomiting in dogs worldwide. While cases of CCoV have been reported in China, specific instances in the Guangxi Zhuang Autonomous Region-a major center for dog breeding and consumption-have not been documented. In this study, we collected spleen tissue samples from dogs in Yulin city and conducted meta-transcriptomic sequencing. Bioinformatics analysis confirmed CCoV presence in these samples. Furthermore, virus screening and phylogenetic analyses identified the circulation of two CCoV genotypes within the dog population, revealing an overall prevalence of 14.2 %, with CCoV-IIb being the predominant genotype. Notably, two significant recombination events were detected among the analyzed strains. These findings provide valuable insights into the presence and genetic diversity of CCoV Yulin's dog populations, enhancing the understanding of its genetic variation and evolution.

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 epidemiological investigation and recombination analysis of Cachavirus prevalent in China

Chaphamaparvovirus carnivoran1 (canine Chaphamaparvovirus, also known as Cachavirus [CachaV]) is a novel parvovirus first reported in dog feces collected from the United States in 2017 and China in 2019. To continuously track its infection and evolution status, 276 canine anal swabs were obtained from pet hospitals in central, northern, and eastern China between 2021 and 2023 and screened via polymerase chain reaction; subsequently, a systematic study was conducted. Of these samples, nine (3.3%) were positive for CachaV. Using polymerase chain reaction, whole genome sequences of the nine CachaV-positive strains were amplified. The NS1 amino acid sequence identity between CachaV strains from China and other countries was 96.23-99.85%, whereas the VP1 protein sequence identity was 95.83-100%. CHN230521 demonstrated the highest identity for NS1 amino acids (99.85%) and VP1 amino acids (100%) with NWT-W88 and CP-T015. According to the model prediction of CHN220916-VP1 protein, Met64Thr, Thr107Ala, and Phe131Ser mutations may cause tertiary structural changes in VP1 protein. Interestingly, each of the nine CachaV strains harbored the same site mutations in NS1 (Ser252Cys, Gly253Leu, and Gly254Thr). Although no explicit recombination events were predicted, the clustering and branching of the phylogenetic tree were complicated. Based on the evolution trees for VP1 and NS1, the nine CachaV strains identified from 2021 to 2023 were closely related to those identified in gray wolves and cats. This study may be beneficial for evaluating the prevalence of CachaVs in China, thereby understanding the evolution trend of CachaVs.

Retrospective Detection and Phylogenetic Analysis of Cachavirus-Related Parvoviruses in Dogs in China

Cachavirus (CachaV) infection was first reported in the USA in 2019. This virus has been previously detected in pet dogs and cats in China. In the present study, we retrospectively examined this virus in 413 dogs and 127 cats. Swab samples obtained from these animals were collected during 2015-2017. Notably, CachaV was detected in four samples from dogs with diarrhea but not in cats; however, the correlation between healthy dogs and those with enteritis was not statistically significant. Furthermore, we amplified early complete genomic sequences of the four strains detected in our study dogs (CHN1601, CHN1602, CHN1703, and CHN1704). Among these strains, the sequence identity of the NS1 protein and the seven previously reported strains in China were 97.44%-99.7%, whereas that of VP1 protein was 98.02%-99.6%. Interestingly, in the NS1 coding region, CHN1704 demonstrated 99.7% (highest) similarity with the CachaV strain NWT-W88 detected from a wolf and 64.5% similarity with the NS1 of a bat parvovirus (BtPV) strain. Conversely, in the VP1 coding region, CHN1703 demonstrated 99.7% (highest) similarity with the prototype CachaV strain IDEXX1 detected from dogs and 63.3% similarity with BtPV strain. For the phylogenetic analysis of NS1 and VP1, the four strains detected during 2016-2017 were merged with other Chinese and foreign CachaV strains to form the major branch. We believe that these results helped improve the understanding of how CachaV evolved and suggest that the virus has been circulating in China since at least March 2016.

Molecular Characterization of Feline Chaphamaparvovirus (Carnivore chaphamaparvovirus 2) Firstly Detected in Dogs from China

A new type of parvovirus known as feline chaphamaparvovirus (FeChPV) was discovered in the feces of shelter cats in Canada in 2019, and >50% of cats were reported to be infected with this virus. In this study, two FeChPV-positive samples were identified from the rectal swabs of 285 dogs with diarrhea but none in 50 healthy dogs. Whole genome sequences of these two FeChPV strains (OQ162042 and OQ162043) were amplified and compared with those of the two viruses originally discovered in Canada (IDEXX-1 and VRI849). The whole genome, NS1, and VP1 of the two FeChPV strains shared a high identity of 95.0%-97.8% nucleotide, 96.9%-98.6% amino acid (aa), and 97.2%-98.8% aa with the reported FeChPV strains, respectively. The phylogenetic tree of NS1 and VP1 revealed that two FeChPV strains, namely, CHN20201025 and CHN20201226, were closely clustered with the two FeChPV prototypes detected in Canada in a group. Moreover, CHN20201025 and CHN20201226 were obviously different from Carnivore chaphamaparvovirus 1 and were classified as Carnivore chaphamaparvovirus 2. This is the first study to report the identification of FeChPV in fecal samples from dogs in China, and the genetic analysis of the FeChPV, which was previously detected in Canadian cats, would improve our understanding of its host spectrum.

Prevalence and genetic diversity of canine coronavirus in northeastern China during 2019-2021

Canine coronavirus (CCoV) is associated with diarrhea in dogs, with a high incidence and sometimes even death. However, there is currently limited information about its prevalence and molecular characterization in northeastern China. Therefore, in this study, we examined 325 canine fecal specimens in four provinces in northeastern China from 2019 to 2021. PCR results revealed that 57 out of 325 (17.5%) samples were found to be positive for CCoV, and the positive rate varies obviously with city, season, age and so on. High incidence (65%) of viral co-infection was detected in the diarrhea samples and mixed infection of distinct CCoV genotypes occurs extensively. More importantly, sequence analysis showed that the S gene has a strong mutation. Phylogenetic analysis demonstrated that CCoV-I and CCoV-II strains has different origins. In particular, we found the CCoV-IIa strains of S gene sequenced and the reference strain B906_ZJ_2019 were highly clustered, and the reference strain was a recombinant strain of CCoV-I and CCoV-II. Our findings provide useful orienting clues for evaluating the pathogenic potential of CCoV in canines, and point out more details on characterization in northeastern China. Further work is required to determine the significance and continuous genetic evolution of CCoV.

Does the novel coronavirus use the ocular surface as an entrance into the body or as an infection site?

This study attempts to review whether the coronavirus disease-2019 (COVID-19) is transmitted through the ocular surface and examine the symptoms and signs of ocular disease. Considering that COVID-19 is transmitted by airborne droplets and close contact with infected individuals, we will also review the conditions to which eye clinics and ophthalmologists should pay attention to prevent the transmission of the disease. Although some researchers have argued that COVID-19 transmission cannot occur through the ocular surface, most of them are of the opinion that the ocular surface is a potential pathway of transmission. Until date, ocular signs and symptoms have been rarely reported in the COVID-19 patients. However, there are case reports of conjunctivitis as the first, and rarely, the only clinical symptom of the disease. In addition, low coronavirus RNA positivity can be detected in the ocular surface samples. Further laboratory and clinical investigations are needed to ascertain whether the ocular surface is one of the potential transmission pathways through which severe acute respiratory syndrome-coronavirus 2 can gain entry into the human body.

Identification and phylogenetic analysis of two canine coronavirus strains

Canine coronavirus (CCoV), a member of the genus Alphacoronavirus, is an enveloped, single-stranded positive-sense RNA virus that responsible for gastroenteritis in dogs. In this study, two CCoV isolates were successfully propagated from 53 CCoV-positive clinical specimens by serial passaging in A-72 cells. These two strains, CCoV JS1706 and CCoV JS1712, caused cytopathic effects in A-72 cells. The sizes of virus plaque formed by them differed in early passages. Electron microscopy revealed a large quantity of typical coronavirus particles with 80–120 nm in diameter in cell culture media and cytoplasm of infected cells, in which they appeared as inclusion bodies. RT-PCR analysis of S gene indicated that these two isolates were belonged to CCoV IIa subtype. Homology of RdRp, S, M and N proteins between the two strains were 100, 99.6, 99.2 and 100.0%, respectively, whereas they were 99.4–100%, 83.1–95.2%, 88.5–99.2% and 91.9–99.7% identity compared to CCoV II reference strains. Phylogenetic analysis of RdRp, S, M and N protein showed that they were closely related to CCoV II strains. These two subtype IIa isolates will be useful for evaluating the pathogenesis and evolution of CCoV and for developing diagnostic reagents and vaccines.

Identification of a canine coronavirus in Australian racing Greyhounds

Coronavirus infection can cause a range of syndromes, which in dogs can include mild-to-severe enteritis that generally resolves rapidly. Fatalities can occur from coinfection with other pathogens, including canine parvovirus. Between late December 2019 and April 2020, canine coronavirus (CCoV) was detected in Australian racing Greyhounds that displayed signs of gastrointestinal disease. The CCoV was genotyped using high-throughput sequencing, recovering 98.3% of a type IIb CCoV, generally thought to cause a mild but highly contagious enteric disease. The Australian CCoV was almost identical (99.9%, whole-genome sequence) to another CCoV associated with an outbreak of severe vomiting in dogs in the United Kingdom at the same time (December 2019-March 2020).

Evolution, Interspecies Transmission, and Zoonotic Significance of Animal Coronaviruses

Coronaviruses are single-stranded RNA viruses that affect humans and a wide variety of animal species, including livestock, wild animals, birds, and pets. These viruses have an affinity for different tissues, such as those of the respiratory and gastrointestinal tract of most mammals and birds and the hepatic and nervous tissues of rodents and porcine. As coronaviruses target different host cell receptors and show divergence in the sequences and motifs of their structural and accessory proteins, they are classified into groups, which may explain the evolutionary relationship between them. The interspecies transmission, zoonotic potential, and ability to mutate at a higher rate and emerge into variants of concern highlight their importance in the medical and veterinary fields. The contribution of various factors that result in their evolution will provide better insight and may help to understand the complexity of coronaviruses in the face of pandemics. In this review, important aspects of coronaviruses infecting livestock, birds, and pets, in particular, their structure and genome organization having a bearing on evolutionary and zoonotic outcomes, have been discussed.

A multiplex nanoparticle-assisted polymerase chain reaction assay for detecting three canine epidemic viruses using a dual priming oligonucleotide system

A rapid and accurate diagnosis of mixed viral infections is important for providing timely therapeutic interventions. The aim of this study was to develop a highly sensitive and specific method for the simultaneous detection of canine distemper virus (CDV), canine parvovirus (CPV) and canine coronavirus (CCV) in mixed infections by combining the high specificity of a dual priming oligonucleotide (DPO) primer system with the high sensitivity of a nanoparticle-assisted PCR (nanoPCR) assay. Under the optimised assay conditions, the multiplex DPO-nanoPCR assay developed using DPO primers was 100-fold more sensitive than the multiplex PCR assay using conventional primers. The detection limits of the multiplex DPO-nanoPCR assay for the recombinant plasmids containing the cloned CDV, CPV and CCV target sequences were 5.4 × 10², 6.5 × 10² and 1.6 × 10² copies in a 25 μL assay, respectively. No cross-reaction with other canine viruses was observed. This is the first reported use of a multiplex nanoPCR assay with the DPO primer system for the simultaneous detection of CDV, CPV and CCV in mixed infections. The high sensitivity and specificity of the assay indicated its potential for use in clinical diagnosis and field surveillance of animal epidemics.

Drawing Comparisons between SARS-CoV-2 and the Animal Coronaviruses

The COVID-19 pandemic, caused by a novel zoonotic coronavirus (CoV), SARS-CoV-2, has infected 46,182 million people, resulting in 1,197,026 deaths (as of 1 November 2020), with devastating and far-reaching impacts on economies and societies worldwide. The complex origin, extended human-to-human transmission, pathogenesis, host immune responses, and various clinical presentations of SARS-CoV-2 have presented serious challenges in understanding and combating the pandemic situation. Human CoVs gained attention only after the SARS-CoV outbreak of 2002-2003. On the other hand, animal CoVs have been studied extensively for many decades, providing a plethora of important information on their genetic diversity, transmission, tissue tropism and pathology, host immunity, and therapeutic and prophylactic strategies, some of which have striking resemblance to those seen with SARS-CoV-2. Moreover, the evolution of human CoVs, including SARS-CoV-2, is intermingled with those of animal CoVs. In this comprehensive review, attempts have been made to compare the current knowledge on evolution, transmission, pathogenesis, immunopathology, therapeutics, and prophylaxis of SARS-CoV-2 with those of various animal CoVs. Information on animal CoVs might enhance our understanding of SARS-CoV-2, and accordingly, benefit the development of effective control and prevention strategies against COVID-19.

Molecular characterization of Cachavirus firstly detected in dogs in China

Canine Cachavirus was novel parvovirus species has been firstly identified in dogs in USA and was classified within the proposed Chaphamaparvovirus genus. To investigate Cachavirus infection in dogs in China, 408 rectal swabs from healthy and diarrheic dogs obtained during 2018-2019 were screened. The rate of Cachavirus positivity was 0% and 1.55% in healthy or diarrheic dogs, respectively. However, statistical analysis suggested no association between the presence of the virus and clinical signs (p > 0.05). Nucleotide identity was 98.2%-98.9% for NS1 and 98.6%-99.1% for VP1, and amino acid identity was 97.9%-98.7% for NS1 and 98.8%-99.6% for VP1 between the five Chinese strains and Cachavirus-1A and Cachavirus-1B detected in the United States. Phylogenetic analysis also indicated that these Cachavirus strains are genetically related to Cachavirus-1A and Cachavirus-1B. This study confirms the presence of Cachavirus in pet dogs in China and provides novel findings on its molecular characteristics.

Etiology and genetic evolution of canine coronavirus circulating in five provinces of China, during 2018-2019

As the outbreaks of COVID-19 in worldwide, coronavirus has once again caught the attention of people. Canine coronavirus is widespread among dog population, and sometimes causes even fatal cases. Here, to characterize the prevalence and evolution of current circulating canine coronavirus (CCoV) strains in China, we collected 213 fecal samples from diarrheic pet dogs between 2018 and 2019. Of the 213 samples, we found 51 (23.94%) were positive for CCoV. Co-infection with canine parvovirus (CPV), canine astrovirus (CaAstV), canine kobuvirus (CaKV), Torque teno canis virus (TTCaV) were ubiquitous existed. Mixed infection of different CCoV subtypes exists extensively. Considering the limited sequences data in recent years, we sequenced 7 nearly complete genomes and 10 complete spike gene. Phylogenetic analysis of spike gene revealed a new subtype CCoV-II Variant and CCoV-IIa was the most prevalent subtype currently circulating. Moreover, we identified strain B906_ZJ_2019 shared 93.24% nucleotide identifies with previous strain A76, and both of them clustered with CCoV-II Variant, which were not well clustered with the known subtypes. Recombination analysis of B906_ZJ_2019 indicated that strain B906_ZJ_2019 may a recombinant variant between CCoV-I and CCoV-II, which is consistent with strain A76. Furthermore, amino acid variations widely existed among current CCoV-IIa strains circulating in China and the classic CCoV-IIa strains, in spite of the unknown functions. In a word, we report a useful information as to the etiology and evolution of canine coronavirus in China based on the available sequences, which is urgent for the devise of future effective disease prevention and control strategies.

Can the Coronavirus Disease 2019 (COVID-19) Affect the Eyes? A Review of Coronaviruses and Ocular Implications in Humans and Animals

In December 2019, a novel coronavirus (CoV) epidemic, caused by the severe acute respiratory syndrome coronavirus - 2 (SARS-CoV-2) emerged from China. This virus causes the coronavirus disease 2019 (COVID-19). Since then, there have been anecdotal reports of ocular infection. The ocular implications of human CoV infections have not been widely studied. However, CoVs have been known to cause various ocular infections in animals. Clinical entities such as conjunctivitis, anterior uveitis, retinitis, and optic neuritis have been documented in feline and murine models. In this article, the current evidence suggesting possible human CoV infection of ocular tissue is reviewed. The review article will also highlight animal CoVs and their associated ocular infections. We hope that this article will serve as a start for further research into the ocular implications of human CoV infections.