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In August 2023, we identified a case of dengue fever in Yantai City, which was imported from Xishuangbanna, China. To investigate its evolutionary history and population dynamics, we utilized the metatranscriptomic method to obtain the virus' whole genome sequence. Together with 367 selected dengue virus whole genome sequences from the NCBI database, we constructed a time-scaled Maximum Clade Credibility (MCC) tree. We found that our sequence exhibited a high homology with a sequence of DENV1 (OR418422.1) uploaded by the Guangzhou Center for Disease Control and Prevention in 2023, with an estimated divergence time around 2019 (95% HPD: 2017–2023), coinciding with the emergence of SARS-CoV-2. The DENV strain obtained in this study belongs to genotype I of DENV1. Its ancestors experienced a global epidemic around 2005 (95% HPD: 2002–2010), and its progeny strains have spread extensively in Southeast Asia and China since around 2007 (95% HPD: 2006–2011). The Bayesian skyline plot indicates that the current population of DENV1 has not been affected by SARS-CoV-2 and is expected to maintain stable transmission. Hence, it is imperative to track and monitor its epidemiological trends and genomic variations to prevent potential large-scale outbreaks in the post-SARS-CoV-2 era. [ABSTRACT FROM AUTHOR]

To investigate the diversity and evolution of noroviruses in Yantai in recent years, this study focused on the coat protein regions of norovirus‐positive samples with nucleic acid detection (cycle threshold) values below 30 between 2017 and 2019. A total of 81 sequences were obtained for genotyping. Initially, a high‐throughput sequencing approach was established to perform the whole‐genome sequencing of multiple typical diarrheal strains. Using bioinformatics software such as BEAST, recombinant variant analysis was performed for each genotype of the norovirus strains, and genetic evolutionary analysis was conducted for the dominant strain GII.4, as well as the rare variant GII.21. The results showed that there were multiple genotypes such as GI.3, GI.6, GI.7, GII.1, GII.2, GII.3, GII.4, GII.6, GII.13, GII.17, GII.21, and GIX.1 in the positive samples of norovirus from 2017 to 2019. GII.4 is characterized by diverse genotypes, with new changes in antigenic epitopes occurring during the course of the epidemic. This may have led to the emergence of a new pandemic. This suggests a need to strengthen surveillance. The results of this study suggest that attention should be paid to the predominant genotypes prevalent in neighboring countries and regions, and the safety supervision of imported food should be strengthened to aid in the prevention and control of related viruses. [ABSTRACT FROM AUTHOR]

Based on the first principles density functional theory calculations, taking the spin-orbit coupling effect into account, we systemically investigated the structure, electronic and optical properties of two-dimensional monolayer and bilayer buckled Bismuthene (b-Bismuthene). The simulations showed that the band structure of the monolayer and bilayer b-Bismuthene can be easily modified by the biaxial and vertical stains, resulting in the optical properties enhancement in the mid-infrared (MIR) regime. In addition, we found that the point defects (in terms of substitution and vacancy) could also modify the electronic and optical properties. In the MIR region, both substitution and vacancy can increase the absorption coefficients of b-Bismuthene. Our results confirmed that the b-Bismuthene could be very attractive for the photonic and nonlinear optical applications in the MIR region. [ABSTRACT FROM AUTHOR]

This study aimed to analyse the pathogenic spectrum and epidemiological characteristics of infectious diarrhea in Yantai City, Shandong Province, China and provide a reference for its prevention and control. A total of 713 stool specimens collected within 3 days of diarrhea onset from January to December 2017 at secondary or higher hospitals in Yantai City were tested for 10 causative pathogens, using real-time polymerase chain reaction (RT-PCR). The top two rotaviruses and norovirus were analysed for typing and geographical distribution. The total positive rate was 46.56% (332/713), and 268 of 713 specimens contained at least one pathogen; 64 had at least two pathogens, accounting for 19.28% of the positive specimens (64/332). The positivity rates of rotavirus (RV), norovirus (NoVs) GI, norovirus (NoVs) GII, enterovirus universal (EV), enteric adenoviruses (EAdV), sapovirus (SaV), astrovirus (Astv), Salmonella (SE), Listeria monocytogenes (LiMo), and Vibrio parahaemolyticus (VP) were 20.06% (143/713), 1.82% (13/713), 12.84% (89/713), 10.66% (76/713), 4.07% (29/713), 0.42% (3/713), 2.38% (17/713), 1.54% (11/713), 1.82% (13/713), and 1.54% (11/713), respectively. Infectious diarrhea showed a high prevalence in young children aged 1-5 years, accounting for 48.6% of the total number of cases. Bacterial diarrhea was predominant in summer, and viral diarrhea was distributed throughout the year, without a significant seasonal pattern. Rotavirus is dominated by G9P, accounting for 81.82%, while norovirus is dominated by the GII type and has diverse characteristics. The aetiology of infectious diarrhea in Yantai is mainly viral, with RV, NoVs, EV, EAdV, and Astv being the most frequent pathogens. Continuous surveillance of infectious diarrhea diseases can help us understand its epidemiological and pathogenic characteristics, thereby taking targeted preventive and control measures in different seasons. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic underscored the critical importance of biosafety in microbiology laboratories worldwide. In response, China has ramped up its efforts to enhance biosafety measures within its Centers for Disease Control and Prevention (CDC) laboratories. This study provides the first comprehensive assessment of biosafety practices across provincial, city, and county levels of CDC microbiology laboratories in China., Methods: We conducted a nationwide cross-sectional survey from 2021 to 2023, targeting staff from microbiology laboratories within CDCs at all administrative levels in China. Stratified sampling was employed to select respondents, ensuring a representative mix across different CDC hierarchies, job titles, and academic qualifications. The survey encompassed questions on biosafety training, the presence of BSL-2 and BSL-3 laboratories, adherence to general biosafety guidelines, and management practices regarding specimens, reagents, and consumables. Statistical analysis was performed to identify significant differences in biosafety practices among different CDC levels., Results: A total of 990 valid responses were received, highlighting a nearly universal presence (98.69%) of BSL-2 laboratories and a significant yet varied presence of BSL-3 laboratories across the CDC network. The survey revealed high levels of biosafety training (98.69%) and adherence to biosafety protocols. However, challenges remain in the consistent application of certain safety practices, especially at lower administrative levels. Notable differences in the management of specimens, reagents, and consumables point to areas for improvement in ensuring biosecurity., Conclusion: Our findings indicate a robust foundation of biosafety practices within CDC microbiology laboratories in China, reflecting significant advancements in the wake of the Biosecurity Law's implementation. Nevertheless, the variability in adherence to specific protocols underscores the need for ongoing training, resources allocation, and policy refinement to enhance biosafety standards uniformly across all levels. This study's insights are crucial for guiding future improvements in laboratory biosafety, not just in China but potentially in other countries enhancing their public health infrastructures., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Niu, Sun, Zhang, Zhao, Tian, Cheng, Zheng, Guo, Zhang, Ma and Wang.)

Background: Analysis of the pathogenic spectrum, epidemiological characteristics and molecular epidemiological features of important pathogens of infectious diarrhea in Yantai City, Shandong Province, 2018-2019, were analyzed to provide a reference basis for the prevention and control of infectious diarrhea., Methods: A total of 1514 stool specimens were collected within 3 days of the onset of diarrhea in secondary or higher hospitals in Yantai from 2018-2019, and all specimens were tested for the presence of seven major viruses and three major bacteria by employing reverse transcription ploymeraer chain reaction (RT-PCR). Population and seasonal analyses were also performed on positive samples for infectious diarrhea. The top two ranked rotavirus and norovirus were focused on genotyping and analysis of geographical distribution., Results: The study showed that the high prevalence of infectious diarrhea in Yantai, Shandong Province, for two consecutive years in 2018 and 2019 was in young children aged 1-5 years, accounting for 48.6% of the total number of cases. Viral diarrhea was distributed throughout the year with no obvious seasonal distribution, while bacterial diarrhea was predominant in summer. Of 1514 stool specimens, the total positive rate of specimens was 43.92% (665/1514). One pathogen was detected in 507 specimens, two pathogens in 107 specimens, and three pathogens in 44 specimens, with mixed infections accounting for 22.71% of positive specimens (151/665). Viral diarrheal pathogens accounted for 93.23% (620/665) of positive samples. The percentages of positive samples for Rotavirus (RV), Norovirus GI, Norovirus GII, Enterovirus universal (EV), Enteroadenovirus (EAdV), Sapovirus (SaV), Astrovirus (Astv), Salmonella (SE), Listeria monocytogenes (LiMo), and Vibrio parahaemolyticus (VP) were 48.57%, 3.61%, 15.34%, and 10.68% of the total positive samples., Conclusions: This study analyzed in detail the composition of infectious diarrhea pathogen spectrum, pathogen alternation pattern, seasonal distribution and population distribution of pathogens in Yantai City, Shandong Province, 2018-2019, to provide a basis for improving relevant local preventive measures and reducing the disease burden., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gao, Liu, Yu, Wang, Yang, Guo and Sun.)

Objective: Starting 31 July 2021, a SARS-CoV-2 outbreak occurred in Yantai, Shandong Province. The investigation showed that this outbreak was closely related to the epidemic at Nanjing Lukou Airport. In view of the fact that there were many people involved in this outbreak and these people had a complex activity area, the transmission route cannot be analyzed by simple epidemiological investigation. Here we combined the SARS-COV-2 whole-genome sequencing with epidemiology to determine the epidemic transmission route of Yantai., Methods: Thirteen samples of SARS-CoV-2 outbreak cases from 31 July to 4 August 2021 were collected and identified by fluorescence quantitative PCR, then whole-genome deep sequencing based on NGS was performed, and the data were analyzed and processed by biological software., Results: All sequences were over 29,000 bases in length and all belonged to B.1.617.2, which was the Delta strain. All sequences shared two amino acid deletions and 9 amino acid mutations in Spike protein compared with reference sequence NC_045512.2 (Wuhan virus strain). Compared with the sequence of Lukou Airport Delta strain, the homology was 99.99%. In order to confirm the transmission relationship between patients, we performed a phylogenetic tree analysis. The results showed that patient 1, patient 2, and patient 9 belong to an independent branch, and other patients have a close relationship. Combined with the epidemiological investigation, we speculated that the epidemic of Yantai was transmitted by two routes at the same time. Based on this information, our prevention and control work was carried out in two ways and effectively prevented the further spread of this epidemic., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sun, Zhang, Liu, Li, Liu, Tian, Gao, Niu, Zhai, Sun, Tian and Wang.)

Background: This study aimed to assess the correlation between Norovirus (NoV), diarrhea, and raw oysters from the eastern coastal areas of Yantai, Shandong, China., Methods: Marine oysters were selected from the three aquatic markets in Laishan district, Yantai City, in March 2019. Meanwhile, 100 fecal samples were collected from patients with diarrhea from the same areas during the same period. Nucleic acids were extracted from these samples and detected by employing reverse transcription polymerase chain reaction (RT-PCR) for NoV GI/GII. The VP1 gene of the coat protein of NoV was amplified by semi-nested RT-PCR and sequenced. Sequence comparison of VP1 was performed with BioEdit software, and the evolutionary tree was constructed with Mega7.0 software., Results: Of the 151 oysters, 42 (27.8%) were positive for NoV. Among them, 32 (21.2%) were GII-positive, 10 (6.6%) were GI-positive, and one GI VP1 sequence was obtained in the oyster samples. Of 100 fecal samples from patients with diarrhea, 38 were GII-positive and 17 were GI-positive. Totally, 19 GII VP 1 sequences and eight GI VP 1 sequences were obtained. Two G1 VP 1 sequences in two fecal samples showed 98.7% nucleotide sequence identity and 99.1% amino acid sequence identity G1 VP 1 acquired in the oyster sample., Conclusions: The results suggest that oysters may be responsible for the spread of NoV in Yantai, Shandong province, China., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sun, Niu, Jin, Gao, Wang and Ma.)