Genome Sequences of Canine Parvovirus Type 2c Prevalent in Western Mexico.

Canine parvovirus type 2 (CPV-2) is one of the main etiologies of viral gastroenteritis in dogs across the globe. This disease is mainly characterized by the presence of diarrhea, abdominal pain, vomiting, anorexia, and dehydration. This virus is responsible for high mortality and morbidity rates in unvaccinated dogs and those younger than three months. The monitoring of viral variants in our region has demonstrated that in the last seven years, variant CPV-2c has been circulating exclusively, which is unusual if we consider that in the rest of the world, at least two variants co-circulate among dog populations. To the best of our knowledge, no studies in Mexico have reported genomic sequences of CPV-2, which are relevant for population comparisons at the genetic level. Therefore, the present study aimed to sequence genomes associated with CPV-2c. To meet this objective, rectal swab samples were collected from dogs with suspected CPV-2 infection. Five positive cases diagnosed by lateral flow testing and polymerase chain reaction were selected for viral genome sequencing. Comparative analyses illustrated that the obtained genome sequences were > 99% homologous to those reported for CPV-2 in the GenBank. On the other hand, 52 nucleotide mutations were identified in the vp1/vp2 gene, out of which three impacted amino acid transition (T226S, F267Y, and A440T). Phylogenetic analysis of the vp1/vp2 gene demonstrated that the five sequences clustered in a clade called "III", pertaining to sequences from USA and Uruguay. To our knowledge, this was the first report of genomic sequences associated with CPV-2 in Mexico, which is of great relevance for the epidemiological-molecular understanding and evolution of the virus.

Canine parvovirus in North-East India: a phylogenetic and evolutionary analysis.

Canine parvovirus type 2 (CPV-2) infection in dogs is considered as one of the most common cause of morbidity and mortality in young dogs and continues to occur with high incidence worldwide. Despite a single-stranded DNA virus, CPV-2 possesses a high mutation rate which has led to the development of new variants from time to time. These variants are classically classified based on the amino acid markers present in the VP2 gene. In this study, we examined 20 different cases of CPV-2 infection from seven different states of the North East region (NER) of India. The near-complete genome sequences of all these isolates were subjected to phylodynamic and phylogeographic analysis to evaluate the genetic diversity and geographical spread of CPV-2 variants. Analysis of the deduced amino acid sequences revealed residues characteristic of the 'Asian CPV-2c lineage' in all the 20 sequences confirming it as the dominant strain circulating in NER, India. The phylogenetic analysis based on the whole genome showed that all 20 sequences formed a monophyletic clade together with other Asian CPV-2c sequences. Furthermore, phylogeographic analysis based on the VP2 gene showed the likely introduction of Asian CPV-2c strain to India from China. This study marks the first comprehensive report elucidating the molecular epidemiology of CPV-2 in India.

Isolation and genetic characterization of parvoviruses from domestic cats reveals emergence of CPV-2c in India: A first report.

The objective of the present study was to isolate and characterize the VP2 gene of parvoviruses from domestic cats in India. For that, 38 fecal samples were screened by PCR with 36.84% positivity. Sequence analysis of those isolates showed canine parvovirus type-2c (CPV-2c) as the predominant variant, followed by feline panleukopenia virus (FPV) and 2a. Phylogenetic analysis of the CPV-2c sequences revealed clustering with Singaporean, South Korean, Mongolian and Bangladeshi dog 2c sequences. Phylogenetic analysis of the 2a isolate (MZC 2) was found to be clustered with Indian, Thai and Singaporean dog 2a isolates. Similarly, all the four FPV sequences were ancestrally related to Indian dog and cat FPV sequences hinting towards interspecies transmission between dogs and cats. Both synonymous and non-synonymous mutations were evident in CPV-2c, 2a and FPV sequences indicative of active evolution. In cell culture medium, CPV-2 showed cytopathogenic effects at the third passage level. In conclusion, the study provided the first report of CPV-2c in cats from India, which demands for extensive epidemiological surveillance to monitor interspecies spread and to shed more light on viral phylogenomics, their distribution in the country and in the Southeast Asian region and usage of current vaccines.

Whole-genome sequence analysis of canine parvovirus reveals replacement with a novel CPV-2c strain throughout India.

Canine parvovirus (CPV) infection causes severe gastroenteritis in canines, with high mortality in puppies. This virus evolved from feline panleukopenia virus by altering its transferrin receptor (TfR), followed by the emergence of CPV-2 variants in subsequent years with altered immunodominant amino acid residues in the VP2 protein. While previous studies have focused on the VP2 gene, there have been fewer studies on non-structural protein (NS1 and NS2) genes. In the present study, CPV genome sequences from clinical samples collected from canines throughout India in 2023, previous Indian CPV isolates from 2009-2019, and the current Indian CPV vaccine strain were compared. The study showed that the CPV-2c (N426E) variant had almost completely replaced the previously dominant CPV-2a variant (N426) in India. The Q370R mutation of VP2 was the most common change in the recent CPV-2c strain (CPV-2c 370Arg variant). Phylogenetic analysis showed the existence of three clades among the recent CPV-2c strains, and sequence analysis identified several new sites of positive selection in the VP1 (N-terminus), VP2, NS1, and NS2 protein-encoding genes in recent CPV strains, indicating the emergence of new CPV-2c variants with varied antigenic and replication properties. The predominant 'CPV-2c 370Arg variants' were grouped with the Chinese and Nigerian CPV-2c strains but were separate from the CPV vaccine strain and earlier isolates from our repository. VP2 epitope analysis predicted nine amino acid variations (including two new variations) in four potential linear B-cell epitopes in the CPV-2c 370Arg variants that might make vaccine failure more likely. This pan-Indian study lays the foundation for further research concerning the dynamics of virus evolution and understanding genetic mutations.

Comparative genomics of canine parvovirus in South America: Diversification patterns in local populations.

Canine parvovirus (CPV) is a significant pathogen in domestic dogs worldwide, causing a severe and often fatal disease. CPV comprises three antigenic variants (2a, 2b, and 2c) distributed unevenly among several phylogenetic groups. The present study compared genetic variability and evolutionary patterns in South American CPV populations. We collected samples from puppies suspected of CPV infection in the neighboring Argentina and Uruguay. Antigenic variants were preliminarily characterized using PCR-RFLP and partial vp2 sequencing. Samples collected in Argentina during 2008-2018 were mainly of the 2c variant. In the Uruguayan strains (2012-2019), the 2a variant wholly replaced the 2c from 2014. Full-length coding genome and vp2 sequences were compared with global strains. The 2c and 2a strains fell by phylogenetic analysis into two phylogroups (Europe I and Asia I). The 2c strains from Argentina and Uruguay clustered in the Europe I group, with strains from America, Europe, Asia, and Oceania. Europe I is widely distributed in South America in the dog population and is also being detected in the wildlife population. The 2a strains from Uruguay formed the distinct Asia I group with strains from Asia, Africa, America, and Oceania. This Asia I group is increasing its distribution in South America and worldwide. Our research reveals high genetic variability in adjacent synchronic samples and different evolutionary patterns in South American CPV. We also highlight the importance of ancestral migrations and local diversification in the evolution of global CPV strains.

First identification of canine parvovirus -2a/2b variant in unvaccinated domestic dogs with gastrointestinal signs in Türkiye.

BACKGROUND: Canine parvovirus type 2 (CPV-2) is the most common enteric virus that infects canids. CPV is the causative agent of a contagious disease defined mostly by clinical gastrointestinal signs in dogs. During the late 1970s, CPV-2 emerged as a new virus capable of infecting domestic dogs and growing across the world. The VP2 gene stands out as a key determinant in the pathogenicity, antigenicity, and host interactions of CPV-2. AIMS: The molecular characterization of the VP2 gene is crucial for understanding CPV evolution and epidemiology. MATERIALS & METHODS: Genes encoding the VP2 protein were sequenced and compared to reference strains worldwide. The maximum likelihood method was used to build a phylogenetic tree using CPV VP2 gene nucleotide sequences. RESULTS: Our phylogenetic analysis of the VP2 gene revealed that five strains were very similar and clustered together, and three strains were in the 2b clade, whereas the other two were in the 2a/2b clade. DISCUSSION: This paper reports the molecular characterization of two novel CPV-2a/2b subtypes in dogs with gastrointestinal symptoms. Genetic analysis was conducted on a CPV genomic region encompassing one of the open reading frames (ORFs) encoding the structural protein VP2. Sequence analysis indicates new and unreported sequence changes, mainly affecting the VP2 gene, which includes the mutations Ser297Ala and Leu87Met. This study represents the first evidence of a new CPV-2a/2b subtype in Türkiye. Due to VP2's crucial role in encoding the capsid protein of CPV-2 and its significant involvement in the host-virus interaction, it is critical to closely monitor its evolutionary changes and be cautious while searching for novel or pre-existing subtypes. CONCLUSION: This study highlights the significance of continuous molecular research for acquiring more insights on the circulation of novel CPV mutants.

Detection of canine parvovirus type 2c (CPV-2c) in Palestine.

INTRODUCTION: The objective of the present study was to report, for the first time, the presence of canine parvovirus type 2c (CPV-2c) in domesticated dogs with acute gastroenteritis and to characterize the antigenic variants circulating in Palestine. METHODOLOGY: A veterinary clinical-based epidemiological study was carried out between December 2022 and April 2023. Fifty fecal samples were collected from dogs with gastroenteritis and screened for CPV-2 infection by polymerase chain reaction. The distribution of positive cases according to various epidemiological factors was studied. Partial sequencing of the viral protein 2 (VP2) gene was performed for the analysis of CPV-2 variants. RESULTS: Most of the investigated samples (60%; n = 50) during the study period were found positive for CPV-2 infection. There was no difference in the distribution of positive cases of CPV-2 infection based on age group, gender, location, and vaccination status. The analysis of nucleotide and amino acid sequences from amplified products, as well as phylogenetic analysis, revealed the presence of CPV-2c clustered with Asian CPV-2c variants. CONCLUSIONS: In summary, this study represents the initial genetic analysis of CPV-2 present in Palestinian dogs with gastroenteritis and provides evidence that confirms the existence of the CPV-2c variants. To determine the prevailing CPV-2 variant associated with the infection, it is crucial to conduct further sequence analysis using large populations of both domestic and wild canines.

Molecular characterization of full-length VP2 gene of canine parvovirus type 2 strains circulating in Egypt 2019-2021.

Canine parvovirus type 2 (CPV-2) is a major cause of fatal gastroenteritis and myocarditis in puppies of domestic and wild carnivores. CPV-2 has accumulated changes over time lead to the emergence of three antigenic variants CPV-2a, CPV-2b, and CPV-2c. VP2 is the major capsid protein that determines virus antigenicity, and host range. Although the three CPV-2 variants were previously identified in Egypt, most reports covered a restricted geographic region and/or time period, and only analyzed partial fragments of VP2 gene. Therefore, this study was designed to test 100 rectal swabs collected from 7 Egyptian governorates between 2019 and 2021 for CPV-2 using PCR. A total of 65 positive samples were identified, mostly in pure dog breeds of young age. The three variants co-circulated in 2019, while CPV-2b was not detected in 2020 and 2021. The frequency of CPV-2b and CPV-2c was higher in 2019 and 2021, respectively. Analysis of CPV-2 full-length VP2 gene sequence from 19/65 positive samples has identified four common amino acid substitutions F267Y, S297A, A300G, Y324I, which are characteristic for the new CPV-2 variants currently circulating worldwide. Unique substitutions including A5G, G36R, V38E, Q370R, and G392V were recognized in certain samples, and appears to have distinct effect on receptor binding, nuclear translocation, and inter-species transmission. Phylogenetic analysis showed separation of CPV-2 strains into two clades. All strains of this study were classified in clade I with Asian strains. In conclusion, this study provides updated comprehensive molecular analysis of CPV-2 variants in Egypt.

Detection and genetic characterization of circulating canine parvovirus from stray dogs in Shanghai, China.

Canine parvovirus (CPV) is the main cause of viral diarrhea in dogs. CPV became a global disease in 1978 and was endemic all over the world. CPV-2 was the first strain to be identified, but with genetic mutations, new genotypes such as CPV-2a/2b/2c/new-2a/new-2b have emerged. In this study, 128 fecal samples of stray dogs suspected of CPV-2 infection were collected from January to March 2021 in Shanghai, China. All samples were screened by PCR and further analyzed by VP2 gene. The positive rate of CPV-2 was 9.4% (12/128), of which 6 CPV-2 isolates were successfully isolated. Phylogenetic tree analysis showed that 4 isolates were CPV-2c genotype and 2 were new-CPV-2b genotype. VP-2 is a key protein that determines the antigenic properties, host range and receptor binding of cpv-2. The results of VP2 amino acid sequence analysis in this study showed that the CPV-2c isolated strain was the same as the previous strains reported in China, including F267Y, Y324I, Q370R and A5G mutations in addition to the typical N426E mutations. Similarly, in addition to the conventional N426D, S297A, F267Y and Y324I mutations, the new CPV-2b isolate also had a new mutation of T440A. This study further confirmed the prevalence of CPV-2c and new-CPV-2b in Shanghai, and also found a new mutation site of new-CPV-2c, which provided a theoretical basis for further enriching the epidemiological data of CPV-2 in Shanghai, as well as the development of vaccines and the prevention and control of the disease.

Molecular phylogenetic assessment of the canine parvovirus 2 worldwide and analysis of the genetic diversity and temporal spreading in Brazil.

Canine parvovirus type 2 (CPV-2) is a relevant pathogen for dogs and causes a severe disease in carnivore species. CPV-2 reached pandemic proportions after the 1970s with the worldwide dissemination, generating antigenic and genetic variants (CPV-2a, CPV-2b, and CPV-2c) with different pathobiology in comparison with the original type CPV-2. The present study aimed to assess the current global CPV-2 molecular phylogeny and to analyze genetic diversity and temporal spreading of variants from Brazil. A total of 284 CPV-2 whole-genome sequences (WGS) and 684 VP2 complete genes (including 23 obtained in the present study) were compared to analyze phylogenetic relationships. Bayesian coalescent analysis estimated the time to the most recent common ancestor (tMRCA) and the population dynamics of the different CPV-2 lineages in the last decades. The WGS phylogenetic tree demonstrated two main clades disseminated worldwide today. The VP2 gene tree showed a total of four well-defined clades distributed in different geographic regions, including one with CPV-2 sequences exclusive from Brazil. These clades do not have a relationship with the previous classification into CPV-2a, CPV-2b, and CPV-2c, despite some having a predominance of one or more antigenic types. Temporal analysis demonstrated that the main CPV-2 clades evolved within a few years (from the 1980s to 1990s) in North America and they spread worldwide afterwards. Population dynamics analysis demonstrated that CPV-2 presented a major dissemination increase at the end of the 1980s / beginning of the 1990s followed by a period of stability and a second minor increase from 2000 to 2004.

High Prevalence of Antibodies against Canine Parvovirus and Canine Distemper Virus among Coyotes and Foxes from Pennsylvania: Implications for the Intersection of Companion Animals and Wildlife.

Canine distemper virus (CDV) and Canine parvovirus (CPV) can cause deadly infections in wildlife and companion animals. In this report, we screened serum from free-ranging eastern coyotes (Canis latrans; N = 268), red foxes (Vulpes vulpes; N = 63), and gray foxes (Urocyon cinereoargenteus; N = 16) from Pennsylvania, USA, for antibodies (Abs) to CDV and CPV. This comprehensive screening was achieved using a commercially available enzyme-linked immunosorbent assay (ELISA)-based colorimetric assay. Abs to CDV and CPV were detected in 25.4% and 45.5% of coyotes, 36.5% and 52.4% of red foxes, and 12.5% and 68.8% of gray foxes, respectively. Abs to both viruses were detected in 9.7% of coyotes, 19.1% of red foxes, and 12.5% of gray foxes. This study demonstrates significant wildlife exposure in a northeastern state to CDV and CPV. As wildlife species continue to urbanize, the probability of spillover between domestic animals and wildlife will increase. Ongoing surveillance of wildlife for CDV and CPV exposure is warranted. IMPORTANCECanine distemper virus (CDV) and Canine parvovirus (CPV) are significant health threats to domestic dogs (Canis familiaris) and wildlife. CDV and CPV have been identified in diverse vertebrates, including endangered wildlife species. Susceptibility to these viral pathogens varies significantly among geographic regions and between host species. High morbidity and mortality have been reported with infection by either virus in susceptible species, including dogs. As humans and companion animals encroach on wildlife habitat, and as wildlife becomes increasingly urbanized, the potential for transmission between species increases. This study assessed CPV and CDV Ab prevalence in wild canids (eastern coyotes, red foxes, and gray foxes) harvested in Pennsylvania between 2015 and 2020. High Ab prevalence was demonstrated for both viruses in each species. Ongoing monitoring of CPV and CDV in wildlife and increased efforts to vaccinate dogs and prevent spillover events are essential.

Phylogenetic Characteristics of Canine Parvovirus Type 2c Variant Endemic in Shanghai, China.

Canine parvovirus type 2 (CPV-2) has spread and mutated globally over the past 40 years. In the present study, 206 samples from dogs suspected of CPV-2 infection were collected from five veterinary clinics in Shanghai city, China. The average positive rate for CPV-2 was detected to be 40.78% using the PCR method. Using an F81 cell (feline kidney cell) culture, the isolates of three CPV-2c strains were obtained. The near full-length genome sequences of the isolates were determined and submitted to GenBank: CPV-SH2001 (MW650830), CPV-SH2002 (MW811188), and CPV-SH2003 (MW811189). By comparing the amino acid sequences of 12 CPV strains with those of 48 related strains retrieved from GenBank, all of the CPV strains from Shanghai were typed as belonging to a relatively new CPV-2c variant spreading in Asia, with typical amino acid residues (5Gly, 267Tyr, 324Ile, and 370Arg) in the VP2 protein. The divergence time of this new CPV-2c clade was estimated by the phylogenetic tree using the maximum likelihood and RelTime with Dated Tips (RTDT) approaches. Our results indicate that the 426 and 324 VP2 amino acid residues are under strong selection pressure with a posterior probability of 0.966 and 0.943, respectively. Therefore, this study provides insight into the phylogenetic characteristics of the current CPV-2c variant in Shanghai city, China.

Novel Cyclovirus Species in Dogs with Hemorrhagic Gastroenteritis.

Nested PCRs with circovirus/cyclovirus pan-rep (replicase gene) primers detected eukaryotic circular Rep-encoding single-stranded DNA (CRESS DNA) viruses in three (samples CN9E, CN16E and CN34) of 18 canine parvovirus-2-positive fecal samples from household dogs with hemorrhagic gastroenteritis on the Caribbean island of Nevis. The complete genomes of CRESS DNA virus CN9E, CN16E and CN34 were determined by inverse nested PCRs. Based on (i) genome organization, (ii) location of the putative origin of replication, (iii) pairwise genome-wide sequence identities, (iv) the presence of conserved motifs in the putative replication-associated protein (Rep) and the arginine-rich region in the amino terminus of the putative capsid protein (Cp) and (v) a phylogenetic analysis, CN9E, CN16E and CN34 were classified as cycloviruses. Canine-associated cycloviruses CN16E and CN34 were closely related to each other and shared low genome-wide nucleotide (59.642-59.704%), deduced Rep (35.018-35.379%) and Cp (26.601%) amino acid sequence identities with CN9E. All the three canine-associated cycloviruses shared < 80% genome-wide pairwise nucleotide sequence identities with cycloviruses from other animals/environmental samples, constituting two novel species (CN9E and CN16E/34) within the genus Cyclovirus. Considering the feeding habits of dogs, we could not determine whether the cycloviruses were of dietary origin or infected the host. Interestingly, the CN9E putative Rep-encoding open reading frame was found to use the invertebrate mitochondrial genetic code with an alternative initiation codon (ATA) for translation, corroborating the hypothesis that cycloviruses are actually arthropod-infecting viruses. To our knowledge, this is the first report on the detection and complete genome analysis of cycloviruses from domestic dogs.

Molecular Investigation of Canine Parvovirus-2 (CPV-2) Outbreak in Nevis Island: Analysis of the Nearly Complete Genomes of CPV-2 Strains from the Caribbean Region.

To date, there is a dearth of information on canine parvovirus-2 (CPV-2) from the Caribbean region. During August-October 2020, the veterinary clinic on the Caribbean island of Nevis reported 64 household dogs with CPV-2-like clinical signs (hemorrhagic/non-hemorrhagic diarrhea and vomiting), of which 27 animals died. Rectal swabs/fecal samples were obtained from 43 dogs. A total of 39 of the 43 dogs tested positive for CPV-2 antigen and/or DNA, while 4 samples, negative for CPV-2 antigen, were not available for PCR. Among the 21 untested dogs, 15 had CPV-2 positive littermates. Analysis of the complete VP2 sequences of 32 strains identified new CPV-2a (CPV-2a with Ser297Ala in VP2) as the predominant CPV-2 on Nevis Island. Two nonsynonymous mutations, one rare (Asp373Asn) and the other uncommon (Ala262Thr), were observed in a few VP2 sequences. It was intriguing that new CPV-2a was associated with an outbreak of gastroenteritis on Nevis while found at low frequencies in sporadic cases of diarrhea on the neighboring island of St. Kitts. The nearly complete CPV-2 genomes (4 CPV-2 strains from St. Kitts and Nevis (SKN)) were reported for the first time from the Caribbean region. Eleven substitutions were found among the SKN genomes, which included nine synonymous substitutions, five of which have been rarely reported, and the two nonsynonymous substitutions. Phylogenetically, the SKN CPV-2 sequences formed a distinct cluster, with CPV-2b/USA/1998 strains constituting the nearest cluster. Our findings suggested that new CPV-2a is endemic in the region, with the potential to cause severe outbreaks, warranting further studies across the Caribbean Islands. Analysis of the SKN CPV-2 genomes corroborated the hypothesis that recurrent parallel evolution and reversion might play important roles in the evolution of CPV-2.

Canine parvovirus type 2c in Vietnam continues to produce distinct descendants with new mutations restricted to Vietnamese variants.

Viral protein 2 (VP2) of canine parvovirus (CPV) exhibits a high degree of genetic and antigenic diversity. We analyzed 88 Vietnamese CPV-VP2 sequences (1755 bp), 34 from this study and 54 from previous studies, and discovered a new sublineage, "new var.", within the lineage CPV-2c-"new", characterized by the mutation 5G/447M, which is restricted to the Vietnamese isolates. These new mutants appear to have emerged in recent years, accounting for 65.5% of the total. With strong nodal support (98%), the distinct Vietnamese 2c-"new-var." sublineage (5G/426E/447M) was found to be separate from the 2c-"new" sublineage (5G/426E/447I) within the 2c-(Asia)/Asia-2c lineage. Amino acid changes in epitopes of VP2 might have led to the generation of subvariants and affected the antigenicity, immunogenicity, or virulence of the virus, resulting in vaccine failure worldwide.

Analysis of canine parvoviruses circulating in Australia reveals predominance of variant 2b and identifies feline parvovirus-like mutations in the capsid proteins.

Canine parvovirus (CPV) is a major enteric pathogen of dogs worldwide that emerged in the late 1970s from a feline parvovirus (FPV)-like ancestral virus. Shortly after its emergence, variant CPVs acquired amino acid (aa) mutations in key capsid residues, associated with biological and/or antigenic changes. This study aimed to identify and analyse CPV variants and their capsid mutations amongst Australian dogs, to gain insights into the evolution of CPV in Australia and to investigate relationships between the disease and vaccination status of dogs from which viruses were detected. CPV VP2 sequences were amplified from 79 faecal samples collected from dogs with parvoviral enteritis at 20 veterinary practices in five Australian states. The median age at diagnosis was 4 months (range 1-96 months). Only 3.7% of dogs with vaccination histories had completed recommended vaccination schedules, while 49% were incompletely vaccinated and 47.2% were unvaccinated. For the first time, CPV-2b has emerged as the dominant antigenic CPV variant circulating in dogs with parvoviral enteritis in Australia, comprising 54.4% of viruses, while CPV-2a and CPV-2 comprised 43.1% and 2.5%, respectively. The antigenic variant CPV-2c was not identified. Analysis of translated VP2 sequences revealed a vast repertoire of amino acid (aa) mutations. Several Australian CPV strains displayed signatures in the VP2 protein typical of Asian CPVs, suggesting possible introduction of CPV strains from Asia, and/or CPV circulation between Asia and Australia. Canine parvoviruses were identified containing aa residues typical of FPV at key capsid (VP2) positions, representing reverse mutations or residual mutations retained from CPV-2 during adaptation from an FPV-like ancestor, suggesting that evolutionary intermediates between CPV-2 and FPV are circulating in the field. Similarly, intermediates between CPV-2a-like viruses and CPV-2 were also identified. These findings help inform a better understanding of the evolution of CPV in dogs.

A systematic literature review and meta-analysis of characterization of canine parvoviruses 2 prevalent in mainland China.

BACKGROUND: Canine parvovirus 2 (CPV-2) is a pathogenic virus that infects dogs, causing a highly infectious disease. Monitoring CPV-2 spread is an important part of prevention; however, the prevalence and epidemiological characteristics of CPV-2 have not been systematically evaluated and analyzed in mainland China. Therefore, a systematic review and meta-analysis were performed to assess prevalence and epidemiological characteristics of CPV-2 in domestic dogs in mainland China. METHODS: In this study, Chinese and English literature on CPV-2 epidemiology published between January 2006 and December 2019 was evaluated. Regarding meta-analysis, the random-effect model was employed by forest plot with 95% of confidence interval. The number of CPV-2 infections was identified and the pooled prevalence of infection, as well as the epidemiological characteristics, was calculated using meta-analysis. RESULTS: A total of 39 studies (data from 137,844 dogs) met the evaluation criteria and were used in our study. The pooled prevalence of CPV-2 infection in mainland China was 36%. CPV-2 infection were associated with age, breed, sampling season and immunization status, but not with gender, publication time and diagnostic methods. CONCLUSIONS: Our results indicated that CPV-2 is prevalent among dogs in China. It is therefore necessary to carry out continuous surveillance and epidemiological studies of CPV-2. In addition, accordingly, effective measures should be taken to prevent the transmission and spread of CPV-2 among the Chinese dog population.

Genetic and phylogenetic analysis of canine bufavirus from Anhui Province, Eastern China.

Bufavirus is a novel virus associated with canine gastroenteritis. Three strains of bufavirus were first detected in dog feces collected from Anhui province in Eastern China. The near-complete genome sequences were amplified. Sequence alignment showed 98.3-99.5% homology between the three bufavirus strains and reference strains. Phylogenetic analysis showed the distributed viruses forming a cluster of close relationships. Selective pressure analysis of the VP2 region indicated that the canine bufavirus (CBuV) was mainly subject to negative selection during evolution. The negative selection site was located on the residue of B-cell epitopes, indicating minimal change to the virus's immunogenicity. Since this is the first report of CBuV circulating in Anhui Province, this study will provide further understanding of the phylogenetic and molecular characteristics of CBuV and serve as a reference for prevention and vaccine development.

Molecular detection and characterization of Carnivore chaphamaparvovirus 1 in dogs.

Canine chaphamaparvovirus (CaChPV) is a newly recognised parvovirus discovered by metagenomic analysis during an outbreak of diarrhoea in dogs in Colorado, USA, in 2017 and more recently detected in diarrhoeic dogs in China. Whether the virus plays a role as canine pathogen and whether it is distributed elsewhere, in other geographical areas, is not known. We performed a case-control study to investigate the possible association of CaChPV with enteritis in dogs. CaChPV DNA was detected both in the stools of diarrhoeic dogs (1.9 %, 3/155) and of healthy animals (1.6 %, 2/120). All the CaChPV-infected dogs with diarrhea were mixed infected with other enteric viruses such as canine parvovirus (formerly CPV-2), canine bufavirus (CBuV) and canine coronavirus (CCoV), whilst none of the asymptomatic CaChPV positive animals resulted co-infected. The nearly full-length genome and the partial capsid protein (VP) gene of three canine strains, Te/36OVUD/19/ITA, Te/37OVUD/19/ITA and Te/70OVUD/19/ITA, were reconstructed. Upon phylogenetic analyses based on the NS1 and VP aa sequences, the Italian CaChPV strains tightly clustered with the American reference viruses. Distinctive residues could be mapped to the deduced variable regions of the VP of canine and feline chaphamaparvoviruses, considered as important markers of host range and pathogenicity for parvoviruses.

Molecular characterisation of canine parvoviruses from clinical samples and vaccines in Nigeria.

Canine parvovirus (CPV) the causative agent of canine parvovirus enteritis is an intractable pathogen of dogs characterised by mutations, evolutionary changes and eventual vaccine failure. The disease is a serious problem in dogs with limited studies conducted in Nigeria. Therefore, this study was designed to characterise the subtypes of CPV isolates in six commonly used vaccines and 157 clinical samples collected from seven states in Nigeria from June 2016 to March 2018. Faecal samples collected from the clinical cases were subjected to in-clinic immunoassay to detect viral antigens. Polymerase chain reaction (PCR) was used to amplify viral VP2 gene in the samples and commonly used vaccines in Nigeria. Thereafter, PCR products were sequenced and analysed. The result showed that 93.0% of the dogs tested positive for CPV in both assays; 72.8% were puppies less than six months old, with 58.3% of them vaccinated. Partial VP2 gene sequence and phylogenetic analysis of 11 random clinical samples showed that CPV-2c 7(63.6%) and CPV-2a 4(36.4%) were the predominant subtypes in Nigeria; with genetic signatures that are 98.7% to 99.9% closely related to Asian and European strains, respectively. No CPV-2b was detected. Amino acid mutation analysis divulged some imperative transmutation sites: D305Y, Y324I, Q370R, N375D, T440A, Y444S, I447M and Y451C in the isolates. The viruses in the vaccines were characterised as the wild-type CPV. The genetic variability, viral population heterogeneity and phylogenetic linkage with isolates from other countries probably suggest transboundary migrations and local differentiations are contributing to continuous CPV evolution and vaccine failure in Nigeria.