M gene analysis of canine coronavirus strains detected in Korea

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.

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.

Evolutionary genetics of canine respiratory coronavirus and recent introduction into Swedish dogs

Canine respiratory coronavirus (CRCoV) has been identified as a causative agent of canine infectious respiratory disease, an upper respiratory infection affecting dogs. The epidemiology is currently opaque, with an unclear understanding of global prevalence, pathology, and genetic characteristics. In this study, Swedish privately-owned dogs with characteristic signs of canine infectious respiratory disease (n = 88) were screened for CRCoV and 13 positive samples (14.7%, 8.4-23.7% [95% confidence interval (CI)]) were further sequenced. Sequenced Swedish CRCoV isolates were highly similar despite being detected in dogs living in geographically distant locations and sampled across 3 years (2013-2015). This is due to a single introduction into Swedish dogs in approximately 2010, as inferred by time structured phylogeny. Unlike other CRCoVs, there was no evidence of recombination in Swedish CRCoV viruses, further supporting a single introduction. Finally, there were low levels of polymorphisms, in the spike genes. Overall, we demonstrate that there is little diversity of CRCoV which is endemic in Swedish dogs.

Epidemiology and molecular diagnosis of canine coronavirus in Egypt: evaluation of different tests used for its diagnosis

This work aimed to study the epidemiology and molecular detection of existing canine coronavirus (CCoV) strain circulating in Egypt. A total number of 86 dogs with clinical signs suggestive for CCoV infection was subjected to clinical examination and quick immunochromatography (IC) on faecal swabs to detect viral antigen. To identify CCoV viral RNA and S protein gene in blood and faeces, conventional PCR and quantitative RT-PCR were used. All examined dogs showed clinical signs suggestive of CCoV infection. Only 32 out of 86 dogs were positive for IC. Of all samples, 36 showed positive results in PCR and the amplification products from these 36 samples were confirmed as CCoV-S protein partial gene by the analysis of nucleotide sequence. However, the qRT-PCR analysis detected 45 positive samples e.g. more than those of IC or conventional polymerase chain reaction. Statistical evaluation of IC and conventional PCR to the results of qRT-PCR performance showed sensitivity, specificity, accuracy, positive and negative predictive values of 71%, 100%, 84.9%, 100%, 75.9% for IC and 80%, 100%, 89.5%, 100%, 82% for PCR, respectively. Sex and age had no effects on IC and PCR results. The prevalence of CCoV infection among the population of this study was 52.3%. Sequence analysis results proved that CCoV strain 59/08 was the strain, circulating in Egypt among dog populations. PCR products of the CCoV cDNA were closely identical to published CCoV-S partial gene. The NCBI Genbank accession number of sequence of the studied gene (CCoV-S partial gene) in this study was KY655745.

Molecular characterization of canine parvovirus and canine enteric coronavirus in diarrheic dogs on the island of St. Kitts: First report from the Caribbean region

Although canine parvovirus (CPV) and canine enteric coronavirus (CCoV) are important enteric pathogens of dogs and have been studied extensively in different parts of the world, there are no reports on these viruses from the Caribbean region. During 2015–2016, a total of 104 diarrheic fecal samples were collected from puppies and adult dogs, with or without hemorrhagic gastroenteritis, on the Caribbean island of St. Kitts (KNA). By PCR, 25 (24%, n = 104) samples tested positive for CPV. Based on analysis of the complete deduced VP2 amino acid sequences, 20 of the KNA CPV strains were assigned to new CPV-2a (also designated as CPV-2a-297A). On the other hand, the VP2 genes of the remaining 5 strains were partially characterized, or could not be sequenced. New CPV-2a was the predominant CPV variant in St. Kitts, contrasting the molecular epidemiology of CPV variants reported in most studies from nearby North and South American countries. By RT-PCR, CCoVs were detected in 5 samples (4.8%, n = 104). Based on analysis of partial M-protein gene, the KNA CCoV strains were assigned to CCoV-I genotype, and were closely related to CCoV-I strains from Brazil. To our knowledge, this is the first report on detection and genetic diversity of CPV and CCoV in dogs from the Caribbean region, and underscores the importance of similar studies in the other Caribbean islands.

Characterization of canine coronavirus spread among domestic dogs in Vietnam

Canine coronavirus (CCoV) is an important pathogen that causes enteritis in dogs, but there is no information on CCoV infection in Vietnam. To examine the prevalence of CCoV infection among Vietnamese dogs, 201 serum samples were analyzed by virus-neutralization (VN) test. The results showed that antibody against CCoV-II was present in 87 dogs (43.3%). To detect genes of CCoV, fecal samples collected from 30 diarrheic and 50 healthy dogs were examinated by RT-PCR, confirming that 2 diarrheic dogs and 5 healthy dogs were positive for CCoV. Nucleotide sequences of N-terminal region of spike (S) gene indicated that CCoV strains were divided into two subgenotypes, CCoV-IIa and -IIb, respectively. Furthemore, we succeeded in isolating CCoV/dog/HCM47/2015, the isolate was plaque-purified three times, and 3’-terminal one-third of the genome was analyzed. Interestingly, the plaque-purified virus had a large deletion in ORF3abc and E genes (1,165 nt), and a short deletion in ORF7b gene (60 nt), suggesting that these regions are not necessary for in vitro replication of CCoV. Next, the antigenicity between the isolated CCoV-IIb and the other CCoV-IIa was compared by VN test, revealing that antigenicty of the isolated CCoV is equal or higher than that of the other CCoV. In summary, two subgenotypes of CCoV-II are spreading among Vietnamese dogs. The isolated virus with a large deletion after in vitro passage may be useful for the development of vaccine, owing to its antigenicity and efficient viral growth in vitro.

Co-Circulation of Canine Coronavirus I and IIa/b with High Prevalence and Genetic Diversity in Heilongjiang Province, Northeast China

To trace the evolution of canine coronavirus (CCoV), 201 stool samples from diarrheic dogs in northeast China were subjected to reverse transcription-polymerase chain reactions (RT-PCRs) targeting the partial M and S genes of CCoV, followed by an epidemiological analysis. M gene RT-PCRs showed that 28.36% (57/201) of the samples were positive for CCoV; of the 57 positive samples, CCoV-I and CCoV-II accounted for 15.79% (9/57) and 84.21% (48/57), respectively. A sequence comparison of the partial M gene revealed nucleotide homologies of 88.4%-100% among the 57 CCoV strains, and 88.7%-96.2% identity between the 57 CCoV strains and the Chinese reference strain HF3. The CCoV-I and CCoV-II strains exhibited genetic diversity when compared with reference strains from China and other countries. The 57 CCoV strains exhibited high co-infection rates with canine kobuvirus (CaKV) (33.33%) and canine parvovirus-2 (CPV-2) (31.58%). The CCoV prevalence in diarrheic dogs differed significantly with immunization status, regions, seasons, and ages. Moreover, 28 S genes were amplified from the 57 CCoV-positive samples, including 26 CCoV-IIa strains, one CCoV-IIb strain, and one CCoV-I strain. A sequence comparison of the partial S gene revealed 86.3%-100% nucleotide identity among the 26 CCoV-IIa strains, and 89.6%-92.2% identity between the 26 CCoV-IIa strains and the Chinese reference strain V1. The 26 CCoV-IIa strains showed genetic diversity when compared with reference strains from China and other countries. Our data provide evidence that CCoV-I, CCoV-IIa, and CCoV-IIb strains co-circulate in the diarrhoetic dogs in northeast China, high co-infection rates with CaKV and CPV-2 were observed, and the CCoV-II strains exhibited high prevalence and genetic diversity.