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Background: Canine coronavirus (CCoV), canine rotavirus (CRV), canine parvovirus (CPV), and canine distemper virus (CDV) cause gastroenteritis in dogs, and co-infections of these pathogens are common in China. In particular, CCoV and CRV are confirmed to have important zoonotic potential and cause public health issues. It is difficult to diagnose these diseases based only on clinical manifestations and pathological damage. Methods: In this study, four pairs of specific primers and probes targeting the CCoV M, CRV VP7, CPV VP2, and CDV N genes were designed. The reaction conditions, including the primer and probe concentrations, annealing temperatures, and reaction cycles, were optimized for the development of a quadruplex RT-qPCR for the detection of CCoV, CRV, CPV, and CDV. The assay was used to test 1028 clinical samples to validate its application. Results: A quadruplex RT-qPCR was successfully established for the differential detection of CCoV, CRV, CPV, and CDV, with good specificity, high sensitivity, and excellent repeatability. The assay could specifically detect CCoV, CRV, CPV, and CDV without cross-reactivity with the other canine viruses tested. It showed high sensitivity with limits of detection (LOD) of 1.1 × 102 copies/reaction for all four plasmid constructs. It showed excellent repeatability, with 0.05–0.90% intra-assay variation and 0.02–0.94% inter-assay variation. The 1028 clinical samples were tested using the quadruplex RT-qPCR and a reported reference RT-qPCR. The positivity rates of CCoV, CRV, CPV, and CDV were 9.53%, 0.97%, 25.68%, and 5.06% using the developed assay, and 9.05%, 0.88%, 25.68%, and 4.86% using the reference assay, with agreements higher than 99.32%. Conclusion: The results indicated that a rapid and accurate quadruplex RT-qPCR was developed for the detection and differentiation of CCoV, CRV, CPV, and CDV. [ABSTRACT FROM AUTHOR]

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 CachaVpositive 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. [ABSTRACT FROM AUTHOR]

To understand the epidemiological and genetic characteristics of B19V, a multiple-province surveillance of patients with febrile rash illnesses (FRIs) were conducted in China during 2009 ~ 2021. The clinical specimens of 3,820 FRI patients were collected and tested for B19V DNA. A total of 99 (2.59%) patients were positive for B19V, and 49 (49.49%) were children under 5 years old. B19V infections occurred throughout the year without obvious seasonal pattern. Ten NS1-VP1u sequences and seven genome sequences were obtained in this study, identified as subgenotype 1a. Combined with the globally representative genome sequences, no temporal and geographic clustering trends of B19V were observed, and there was no significant correlation between B19V sequences and clinical manifestations. The evolutionary rate of the B19V genome was 2.30 × 10–4 substitutions/site/year. The number of negative selection sites was higher than that of positive selection sites. It was the first to comprehensively describe the prevalence patterns and evolutionary characteristics of B19V in FRI patients in China. B19V played the role in FRI patients. Children under 5 years old were the main population of B19V infection. Subgenotype 1a was prevalent in FRI patients in China. B19V showed a high mutation rate, while negative selection acted on the genome. [ABSTRACT FROM AUTHOR]

Background. Human parvovirus B19 (B19V) is a common contaminant found in plasma pools and plasma derivatives. Previous studies were mainly focused on limited aspects, further assessment of prevalence of B19V DNA and antibodies in plasma donors, the contamination of B19V in pooled plasma and plasma derivatives should be performed in China. Study Design and Methods. Individual plasma donors' samples from four provinces and pooled plasma from four Chinese blood product manufacturers were collected and screened using B19V DNA diagnostic kits between October 2018 and May 2020. The positive samples were investigated for the seroprevalence of B19V antibodies and subjected to sequence analysis and alignment for phylogenetic studies. Moreover, 11 plasma donors who were B19V DNA-positive at their first testing were also followed during the later donation period. Additionally, 400 plasma pools and 20 batches of plasma derivatives produced by pooled plasma with a viral load of B19VDNAexceeding 104IU/mL were also collected and tested for B19V DNA and antibodies. Objectives. To comprehensively and systematically determine the frequency and viral load of B19V DNA in plasma donors, pooled plasma, and plasma derivatives from four Chinese blood product manufacturers. Results. A total of 17,187 plasma donors were analyzed and 44 (0.26%) specimens were found positive for B19V DNA. The quantitative DNA levels ranged from 1.01 101 to 5.09 1012 IU/mL. Forty-four DNA-positive specimens were also investigated for the seroprevalence of B19V antibodies, 75.0% and 2.3% of which were seropositive for B19V IgG and IgM antibodies, respectively. The phylogenic analyses showed that the prevalent genotypes in the four provinces' plasma donors belonged to B19V Genotype 1. Eleven individual plasma donors who were B19V DNA-positive at the first donation were then followed for a period, and in general, the DNA levels of B19V gradually decreased. Moreover, 64.8% (259/400) of the pooled plasma was contaminated by B19V, with concentrations of 1.05 100 3.36 109 IU/mL. Approximately 72.6% of the DNA-positive plasma pools were only moderately contaminated (<104 IU/mL), while 27.4% contained >104 IU/mL. Twenty batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 104IU/mL were also tested. B19V was detected in 5/5 PCC samples and 5/5 factor VIII samples but was not found in the intravenous immune globulin and albumin samples. Conclusion. The contamination of B19V in pooled plasma and plasma-derived clotting factor concentrates is serious. Whether B19V nucleic acid testing (NAT) screening of plasma and plasma derivatives is launched in China, blood product manufacturers should spontaneously perform B19V NAT screening in plasma donors and minipool plasma. These measures can ensure that samples with high titer B19V DNA are discarded in order to prevent and control this transfusion transmitted virus. [ABSTRACT FROM AUTHOR]

Cats are susceptible to panleukopenia virus (FPV) and canine parvovirus type 2 (CPV‐2) infection. FPV has been recognized as relatively conservative in genetic evolution compared to CPV‐2, but information regarding FPV variations in cats is still limited. The aim of this study was to investigate the molecular prevalence of FPV and CPV‐2 variants among cats in China. From April 2019 to December 2021, 193 diarrheal faecal samples of cats were collected from Southwest China and 127 (65.80%) samples tested positive to Carnivore protoparvovirus 1. FPV, CPV‐2 and some their genomic variants were identified from positive samples, indicating a heterogeneous Carnivore protoparvovirus 1 circulation in the cat population in China. Among FPV strains, an A91S FPV mutant reached the detection rate of 39.37%, which showed that this FPV genomic variant has been prevalent in the tested cats. Moreover, 7 strains of A91S FPV variants were isolated and purified successfully using F81 cells, and the genomes were sequenced. Phylogenetic trees based on the nearly complete genomic sequences, VP2 and NS1 nucleotide sequences showed that the A91S FPV variants were located in the FPV clade, but all clustered into a separate branch. Structural prediction showed that A91S mutation in VP2 protein extended the random coil of aa residues from 92–95 to 91–95. Moreover, the analysis of all complete VP2 sequences of FPV and CPV‐2 available in the GenBank database revealed that the A91S FPV variant has been prevalent in China since 2017 and has reported in four other countries in cats. Thus, our study revealed that heterogeneous Carnivore protoparvovirus 1 are circulating in the cat population in China, and first reported the prevalence and genomic characteristics of the A91S FPV variant, which contributed to a better understanding of the molecular prevalence and genetic evolution of FPV in cats. [ABSTRACT FROM AUTHOR]

Background: The red panda has been classified as an endangered species due to the decreased number in the world and disease is considered as a great threat to the health and survival of the cubs in captivity. Results: This study analyzed 32 red panda cub mortalities (15 females and 17 males, age less than two months) through gross necropsy, microbiological examination, and histopathological observation at the Chengdu Research Base of Giant Panda Breeding, China, during 2014–2020. The results showed that screenings for canine distemper virus, canine parvovirus, rotavirus and parasite infection were all negative, however bacteria such as Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Enterococcus faecalis, Pseudomonas were isolated from the tissue samples of some cubs. The major causes of death were respiratory (43.75%) and digestive system disease (28.13%), followed by cardiovascular disease (12.5%) and neonatal stillbirths (9.38%). Renal system diseases and trauma were also detected, at lower incidence (one case for each). The mortality rate within 15 days of birth was 68.75% and gradually decreased with age, there was no significant difference in gender. Conclusion: This study can provide a scientific basis for the analysis of the cause of death among red panda cubs in captivity, so as to improve the survival rate, help build the captive population and further the ex-situ conservation management of this endangered species. Additionally, our research may also provide insights into the in-situ conservation of wild red pandas by identifying emerging disease threats within the wild population and potential treatment for rescued individuals. [ABSTRACT FROM AUTHOR]

In this study, 192 diarrheal fecal samples were collected from 2019 to 2021 for monitoring the molecular prevalence of canine parvovirus 2 (CPV-2) among dogs in Southwest China, and 113 samples were detected as Carnivore protoparvovirus 1-positive. Surprisingly, 28/113 (24.8%) strains were identified as feline parvovirus (FPV)-like viruses based on the key amino acid (aa) residues in VP2. Further, 6 FPV-like strains were successfully isolated and genome sequenced, and phylogenetic trees based on the genome, VP2 and NS1 sequences showed that the 6 FPV-like strains were most genetically related with FPV instead of CPV-2. Interestingly, the VP2 proteins of the FPV-like virus contained all key aa residues typical for FPV and can be 100% identical to that of FPV, but the VP1 intron and NS1 aa sequences exhibited some unique molecular characteristics. The FPV-like isolate could hemagglutinate swine erythrocyte at pH values between 6 and 8, and replicated efficiently in MDCK cell line; moreover, the virus could cause canine systemic infection via oral administration. Further analysis based on VP2 sequences of FPV and CPV-2 in GenBank revealed that the FPV-like virus had already existed among dogs in 4 Asian countries, and have circulated widely in China. This study first confirmed that the FPV-like isolates could efficiently infect dogs, and has been prevalent among dogs in China. Moreover, this study first reported the genome characteristics of the FPV-like virus in dogs, which may represent a novel evolution pattern involving in the cross-species transmission of the virus from cats to dogs. • An FPV-like virus was first found to be prevalent among dogs in China. • The genomes and individual proteins of the FPV-like virus are most genetically related with FPV instead of CPV. • The VP2 proteins can be 100% identical to that of FPV, but the VP1 intron and NS1 exhibit some identical mutations. • The FPV-like virus can cause systemic infection in dogsand effectively proliferate in MDCK cells distinguished from FPV. • The FPV-like virus represents a novel CPV originating from FPV through a novel evolutionary pattern. [ABSTRACT FROM AUTHOR]

Since 2017, outbreaks of gosling astroviruses (GoAstV) causing the major symptoms related to gout in geese have posed a threat to China's poultry industry and caused huge economic losses. In this study, tissue samples from goslings with gout and urate deposition as the main symptoms were taken from 14 goose farms in different regions of China and screened for pathogen infection. The infection rate of GoAstV was 100%, whereas the infection rates of goose parvovirus, reovirus, Tembusu virus, and goose hemorrhagic polyomavirus were 2, 4, 0, and 0%, respectively. In total, 14 GoAstV strains were isolated and their complete genomes were sequenced. Based on the phylogenetic trees, the 14 isolated strains were classified as GoAstV (G-I) and were considered distant from strains belonging to GoAstV (G-II). The multiple sequence alignments indicated a tremendous amount of amino acid mutations in some parts of the encoding proteins of these strains; the main mutations were located in open reading frames (ORFs)—ORF1a and ORF2, such as M533V and F568S in ORF1a and A614T in ORF2. On the other hand, Further, 2 of the 14 GoAstV strains were possibly derived through inter-GoAstV-I recombination. Taken together, these findings indicate that GoAstV s are evolving in a more complex manner and have diverse transmission routes. [ABSTRACT FROM AUTHOR]