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Emerging in December 2019, coronavirus disease 2019 (COVID-19) eventually became a pandemic and has posed a tremendous threat to global public health. However, the origins of SARS-CoV-2, the causative agent of COVID-19, remain to be determined. It has reported that a certain number of the early case clusters had a contact history with Huanan Seafood Market. Therefore, surveillance of SARS-CoV-2 within the market is of vital importance. Herein, we presented the SARS-CoV-2 detection results of 1380 samples collected from the environment and the animals within the market in early 2020. By SARS-CoV-2-specific RT-qPCR, 73 environmental samples tested positive for SARS-CoV-2 and three live viruses were successfully isolated. The viruses from the market shared nucleotide identity of 99.980% to 99.993% with the human isolate HCoV/Wuhan/IVDC-HB-01. In contrast, no virus was detected in the animal swabs covering 18 species of animals in the market. The SARS-COV-2 nucleic acids in the positive environmental samples showed significant correlation of abundance of Homo sapiens with SARS-CoV-2. In summary, this study provided convincing evidence of the prevalence of SARS-CoV-2 in the Huanan Seafood Market during the early stage of COVID-19 outbreak.

What is already known about this topic? Visceral leishmaniasis (VL) is the most serious form of leishmaniasis. In recent years, reported cases of VL have been gradually increasing in Shanxi Province, China. What is added by this report? The report describes the epidemiology of VL from 1950 to 2019 in Shanxi Province and the recent trend of VL reemergence. What are the implications for public health practice? Measures to prevent and control VL, such as health education, improving clinical diagnostics, strengthening epidemiological investigation capacity for VL cases, monitoring surveillance, and use of other evidence-based preventive measures, should be undertaken in Shanxi Province.

Influenza A viruses (IAVs) and influenza B viruses (IBVs) cause annual epidemics in human populations with seasonal circulation spikes. Peptide AM58–66GL9 located at residues 58–66 of M1 protein of IAVs has been recognized as an immunodominant T cell epitope with HLA-A*0201 restriction and broadly used as a positive reference in influenza immunity. This peptide also almost completely overlaps with a nuclear export signal (NES) 59–68 in IAV M1, which explains the limited escape mutations under the T cell immune pressure in this region. In this study, we investigated the potential immunogenicity and NES in the corresponding region of IBV. The long peptide covering this region can be recognized by specific T cells and induce robust expression of IFN-γ among HLA-B*1501 donors in vivo, but not in HLA-A*0201 donors. Among a series of truncated peptides derived from this region, we identified an immunodominant HLA-B*1501–restricted T cell epitope BM58–66AF9 (ALIGASICF) in the M1 protein of IBV. Furthermore, the structure of the HLA-B*1501/BM58–66AF9 complex shows that BM58–66AF9 performs a flat and featureless conformation that is similar to AM58–66GL9 presented by HLA-A*0201. In contrast with IAV, the sequence around residues 55–70 of IBV M1 does not contain an NES. Our comparative study on IBVs and IAVs provides new insights into the immune and evolution characteristics of IBVs and may shed light on vaccine development for influenza viruses.