The outbreak of 2019-nCoV pneumonia (COVID-19) in the city of Wuhan, China has resulted in more than 70,000 laboratory confirmed cases, and recent studies showed that 2019-nCoV (SARS-CoV-2) could be of bat origin but involve other potential intermediate hosts. In this study, we assembled the genomes of coronaviruses identified in sick pangolins. The molecular and phylogenetic analyses showed that pangolin Coronaviruses (pangolin-CoV) are genetically related to both the 2019-nCoV and bat Coronaviruses but do not support the 2019-nCoV arose directly from the pangolin-CoV. Our study also suggested that pangolin be natural host of Betacoronavirus , with a potential to infect humans. Large surveillance of coronaviruses in pangolins could improve our understanding of the spectrum of coronaviruses in pangolins. Conservation of wildlife and limits of the exposures of humans to wildlife will be important to minimize the spillover risks of coronaviruses from wild animals to humans.

Introduction: Pseudorabies (PR) is a highly contagious viral disease caused by the pseudorabies virus (PRV), which can cause disease in a wide range of domestic and wild animals. Studies have shown that new mutant strains have emerged in pig farms in many regions and that commercial inactivated and live attenuated vaccines are becoming less effective at protecting pigs.Methods: Porcine pseudorabies glycoprotein D (gD) gene (GenBank: QEY95774.1) with hexa-His tag to the C terminus for further purification processes was cloned into the lentiviral expression plasmid pLV-CMV-eGFP by restriction enzyme, the resulting plasmid was designated as pLV-CMV-gD. HEK-293T cells with robust and stable expression of recombinant gD protein was established by infection with recombinant lentivirus vector pLV-CMV-gD. We expressed porcine pseudorabies virus gD protein using HEK-293T cells.Results: We describe in this study that individual gD proteins produced by a mammalian cell expression system are well immunogenic and stimulate high levels of PRV-specific and neutralizing antibodies in mice and piglets. All mice and piglets survived lethal doses of PRV, significantly reducing the amount of PRV virus in piglets’ lymph nodes, lungs, spleen, and other tissues. It also significantly reduced the time cycle and amount of viral excretion from piglets to the environment through the nasal and anal cavities.Discussion: The results suggest that PRV gD protein is expected to be a potential candidate for the preparation of genetically engineered PR vaccines for the prevention of PRV infection and the control of PR epidemics.

Proteomics analysis of suckling mouse brain infected with attenuated rabies virus strain SRV9

Circoviruses are a group of small circular, single-stranded DNA viruses that belong to the family Circoviridae. They are known to infect a wide variety of animals. Rhizomys sinensis is a species of rodent that is the reservoir of many zoonotic pathogens. Our previous study identified many sequencing reads mapped to the genome of viruses in Circoviridae in R. sinensis. However, little is known about the circulation and genetic characterization of circoviruses in R. sinensis. This study identified three different circoviruses in samples from 195 R. sinensis. First, the bamboo rat circovirus is widely prevalent in R. sinensis in Guangdong Province, and all strains could be divided into three clades based on nucleotide substitutions at specific sites. Second, and more important, porcine circovirus 2 (PCV2) was isolated for the first time from R. sinensis, which expanded the host range of PCV2 and indicated extra procedures would be required to protect livestock from this virus. Finally, a novel circovirus phylogenetically close to the dromedary stool-associated circular ssDNA virus was detected in 86 (44.1) samples, which may represent a new circovirus species. These results not only expand our understanding of the circovirus diversity in rodents, particularly in R. sinensis, but also underscore the importance of continued surveillance of viruses in wildlife populations, particularly in rodents, to prevent and control the spread of zoonotic pathogens.

Porcine circoviruses disease (PCVD), caused by porcine circovirus (PCVs), is an important swine disease characterized by porcine dermatitis, nephrotic syndrome and reproductive disorders in sows. However, diseases caused by PCV2, PCV3, or PCV4 are difficult to distinguish, so a simple, rapid, accurate and high-throughput diagnostic and identification method is urgently needed to differentiate these three types. In this study, specific primers and probes were designed based on the conserved region sequences of the Rep gene of PCV2, and the Cap gene of PCV3 and PCV4. A multiplex qPCR assay was developed and optimized that the limit of detection concentration could reach as low as 3.8 copies/μL, with all correlation coefficients (R²) exceeding 0.999. Furthermore, the method showed no cross-reaction with other crucial porcine viral pathogens, and both intra-repeatability and inter-reproducibility coefficients of variation were below 2%. The assay was applied to the detection of 738 pig samples collected from 2020 to 2021 in Guangdong Province, China. This revealed positive infection rates of 65.18% for PCV2, 29.27% for PCV3, and 0% for PCV4, with a PCV2/PCV3 co-infection rate of 23.17%. Subsequently, complete genome sequences of 17 PCV2 and 4 PCV3 strains were obtained from the above positive samples and pre-preserved positive circovirus samples. Nucleotide sequence analysis revealed that the 17 PCV2 strains shared 96.7–100% complete nucleotide identity, with 6 strains being PCV2b and 11 strains being PCV2d; the 4 PCV3 strains shared 98.9–99.4% complete nucleotide identity, with 2 strains being PCV3a-1 and 2 strains being PCV3b. This research provides a reliable tool for rapid PCVs identification and detection. Molecular epidemiological investigation of PCVs in pigs in Guangdong Province will help us to understand PCV2 and PCV3 epidemiological characteristics and evolutionary trends.