Analysis of s gene and protein structure difference between porcine coronavirus and SARS-CoV-2

The pandemic of COVID-19 (Corona virus disease 2019) caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) poses a huge threat to human health worldwide since December 2019. In order to study the correlation betweenSARS-CoV-2 and porcine coronavirus, the phylogenetic analysis of spike (S) protein amino acid sequence of human coronavirusand porcine coronavirus, the similarity analysis of the spatial structure of S1 subunit receptor binding domain (RBD) of S proteinwere conducted by bioinformatics analysis, moreover, the double- antigen sandwich ELISA kit was utilized to detect the SARSCoV-2 antibody in common porcine coronavirus positive serum. The results of phylogenetic analysis showed a low identity of Sprotein amino acid sequence between SARS-CoV-2 and porcine coronavirus, indicating a long distance of genetic evolution, andthe S1 subunit RBD spatial structure showed huge differences, meanwhile, all of the porcine coronavirus positive serum samplestested were negative of SARS-CoV-2 antibody. Our data suggested the huge differences in gene and protein level between SARS-CoV-2 and porcine coronavirus, which indicating that SARS-CoV-2 shows a minimal risk of achieving cross-species transmission byinfecting pigs to threaten public health security. This research provides a basis for studying COVID-19 pathogen traceability andbiosafety analysis of cross-species transmission.

Replication, pathogenicity, and transmission of SARS-CoV-2 in minks.

Minks are raised in many countries and have transmitted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans. However, the biologic properties of SARS-CoV-2 in minks are largely unknown. Here, we investigated and found that SARS-CoV-2 replicates efficiently in both the upper and lower respiratory tracts, and transmits efficiently in minks via respiratory droplets; pulmonary lesions caused by SARS-CoV-2 in minks are similar to those seen in humans with COVID-19. We further found that a spike protein-based subunit vaccine largely prevented SARS-CoV-2 replication and lung damage caused by SARS-CoV-2 infection in minks. Our study indicates that minks are a useful animal model for evaluating the efficacy of drugs or vaccines against COVID-19 and that vaccination is a potential strategy to prevent minks from transmitting SARS-CoV-2.

Serological survey of SARS-CoV-2 for experimental, domestic, companion and wild animals excludes intermediate hosts of 35 different species of animals.

The pandemic SARS-CoV-2 has been reported in 123 countries with more than 5,000 patients died from it. However, the original and intermediate hosts of the virus remain unknown. In this study, 1,914 serum samples from 35 animal species were used for detection of SARS-CoV-2-specific antibodies using double-antigen sandwich ELISA after validating its specificity and sensitivity. The results showed that no SARS-CoV-2-specific antibodies were detected in above samples which excluded the possibility of 35 animal species as intermediate host for SARS-CoV-2. More importantly, companion animals including pet dogs (including one dog the SARS-CoV-2 patient kept and two dogs which had close contact with it) and cats, street dogs and cats also showed serological negative to SARS-CoV-2, which relieved the public concerns for the pets as SARS-CoV-2 carriers.