Objective:To analyze the epidemiological, etiological characteristics and transmission of an imported D8 genotype measles case in a child in Shandong Province, August 2023.Methods:A study was conducted on a measles case and 16 contacts in Shandong Province in August 2023. Field epidemiological surveys, including recent exposure and immunization history, were conducted. Serum and throat swab samples were collected from all 16 subjects. Measles IgM and IgG antibody levels and avidity were measured by ELISA, while virus detection and genotyping were performed using fluorescence quantitative PCR and RT-PCR. Genetic evolutionary analysis of the obtained sequences was conducted using MEGA and Beast software.Results:The case was an 11-year-old boy, a fifth-grade student, who developed symptoms on August 28, 2023. A total of five close contacts were investigated, including three family members (grandfather, father and sister) and two playmates. Additionally, 11 classmates who had close contact with the case′s sister during the infectious period (within five days after the rash onset) were also investigated. Among the 16 serum samples tested, only one case was positive for IgM, while the other 15 samples were negative for IgM. The results of the serum antibody avidity test showed that among the 16 serum samples, 14 were positive for IgG. Of these, eight had a relative avidity index >55%, indicating high-avidity antibodies; one had a relative avidity index <45%, indicating low-avidity antibodies; and five had an avidity index between 45% and 55%. The IgG detection OD values for the case′s sister and grandfather were higher than those of the other contacts. Based on the vaccination history of the subjects and the results of IgM and IgG tests, it was preliminarily determined that the case had a recent wild-type measles virus infection. The case′s sister and grandfather had a history of measles wild-type virus infection, while the high-avidity antibodies in the other contacts were likely induced by the measles vaccine. The results of the pharyngeal swab tests showed that only the case was positive for measles virus nucleic acid, while the remaining 15 samples were negative for measles virus. The genetic evolutionary analysis revealed that the viral sequence of this case (Mvs/Shandong.CHN/38.23) had a 100% homology with the Hong Kong strain sequence from August 2023. It belonged to a different transmission chain from the D8 genotype strains that appeared in Shandong Province between 2018 and 2019, with sequence homology ranging from 98.0% to 98.8%. The sequence homology within the transmission chain of this case was between 99.1% and 100%. The evolutionary rate of this transmission chain was approximately 8.38×10 -3 sub/site/year, and the most recent common ancestor was estimated to have emerged around the year 2011. Conclusion:This case is the first imported D8 genotype measles case in Shandong Province. There is no spatio-temporal correlation between this case and adult cases of D8 genotype imported from Shandong Province in 2018-2019, indicating a new D8 genotype imported epidemic.

Objective:To analyze the epidemiological, etiological characteristics and transmission of an imported D8 genotype measles case in a child in Shandong Province, August 2023.Methods:A study was conducted on a measles case and 16 contacts in Shandong Province in August 2023. Field epidemiological surveys, including recent exposure and immunization history, were conducted. Serum and throat swab samples were collected from all 16 subjects. Measles IgM and IgG antibody levels and avidity were measured by ELISA, while virus detection and genotyping were performed using fluorescence quantitative PCR and RT-PCR. Genetic evolutionary analysis of the obtained sequences was conducted using MEGA and Beast software.Results:The case was an 11-year-old boy, a fifth-grade student, who developed symptoms on August 28, 2023. A total of five close contacts were investigated, including three family members (grandfather, father and sister) and two playmates. Additionally, 11 classmates who had close contact with the case′s sister during the infectious period (within five days after the rash onset) were also investigated. Among the 16 serum samples tested, only one case was positive for IgM, while the other 15 samples were negative for IgM. The results of the serum antibody avidity test showed that among the 16 serum samples, 14 were positive for IgG. Of these, eight had a relative avidity index >55%, indicating high-avidity antibodies; one had a relative avidity index <45%, indicating low-avidity antibodies; and five had an avidity index between 45% and 55%. The IgG detection OD values for the case′s sister and grandfather were higher than those of the other contacts. Based on the vaccination history of the subjects and the results of IgM and IgG tests, it was preliminarily determined that the case had a recent wild-type measles virus infection. The case′s sister and grandfather had a history of measles wild-type virus infection, while the high-avidity antibodies in the other contacts were likely induced by the measles vaccine. The results of the pharyngeal swab tests showed that only the case was positive for measles virus nucleic acid, while the remaining 15 samples were negative for measles virus. The genetic evolutionary analysis revealed that the viral sequence of this case (Mvs/Shandong.CHN/38.23) had a 100% homology with the Hong Kong strain sequence from August 2023. It belonged to a different transmission chain from the D8 genotype strains that appeared in Shandong Province between 2018 and 2019, with sequence homology ranging from 98.0% to 98.8%. The sequence homology within the transmission chain of this case was between 99.1% and 100%. The evolutionary rate of this transmission chain was approximately 8.38×10 -3 sub/site/year, and the most recent common ancestor was estimated to have emerged around the year 2011. Conclusion:This case is the first imported D8 genotype measles case in Shandong Province. There is no spatio-temporal correlation between this case and adult cases of D8 genotype imported from Shandong Province in 2018-2019, indicating a new D8 genotype imported epidemic.

Objective:To study the complete genome characterization of Human Astrovirus (HAstV) in Shandong Province.Methods:Stool samples from acute flaccid paralysis (AFP) surveillance in Shandong Province from 2020 to 2022 were collected, and HAstV nucleic acid was examined by real-time quantitative PCR (qPCR). Next-generation sequencing (NGS) was conducted for the positive samples to obtain complete genome sequences and identify the genotype. Homology comparison and phylogenetic analysis were performed by using BioEdit and Mega software.Results:A total of 667 samples were examined by qPCR, of which 14 were HAstV-positive (2.1%), including HAstV-1 ( n=6), MLB1 ( n=6), MLB2 ( n=1), and VA2 ( n=1). The complete genome sequences were obtained from 11 samples. The six HAstV-1 sequences of this study had 98.2% to 99.9% nt similarities with each other and 87.6% to 98.6% with those from other regions. The four MLB1 sequences of this study had 99.1% to 99.9% nt similarities with each other and 92.2% to 99.4% with those from other regions. The VA2 sequence of this study had 96.0% to 96.3% nt similarities with those from other regions. Phylogenetic analysis based on ORF2 region showed that the local HAstV-1 sequences were most closely related to Japanese strains, and had distinct topology with phylogenies based on ORF1a and ORF1b regions. Conclusion:The complete genome sequences of 11 HAstV strains are obtained, and the VA2 complete genome is found.

Objective:The whole genome of one porcine sapelovirus (PSV) strain from mosquitoes captured in Weishan county, Shandong province was sequenced and analyzed its genetic characteristics.Methods:Mosquitoes collected in pigpen in Weishan county of Shandong province in 2021 were homogenized and inoculated on C6/36 and BHK21 cell lines for virus isolation. Virus RNA was extracted from the positive culture and the whole genome was sequenced by next generation sequencing. Phylogenetic analysis, similarity comparison and recombination analysis were conducted via MEGA 7.0.26, BioEdit 7.0.9.0 and Simplot 3.5.1.Results:A PSV strain 265/SD was isolated from Culex tritaeniorhynchus. The clear cytopathic effects characterized by rounding, shrinkage and detachment of cells were observed on BHK21 cells. The whole genome of this study strain was 7 558 nt in length. Phylogenetic analysis based on VP1 sequences indicated that strain 265/SD belonged to traditional genotype. Different positions of 265/SD in the VP1 and 3D phylogenetic trees suggested the recombinant potential. Similarity plot revealed the existence of recombination but the exact origins remained unknown. The similarity analysis of VP1 regions showed that strain 265/SD had low nucleotide identity (77.3%) and amino acid identity (80.3%) with another strain SD/CHN/2016 from Shandong province. Conclusions:Our data enriched the whole genome information of PSV in Shandong province and provided scientific basis for prevention and control of PSV.

Objective:The whole genome of one porcine sapelovirus (PSV) strain from mosquitoes captured in Weishan county, Shandong province was sequenced and analyzed its genetic characteristics.Methods:Mosquitoes collected in pigpen in Weishan county of Shandong province in 2021 were homogenized and inoculated on C6/36 and BHK21 cell lines for virus isolation. Virus RNA was extracted from the positive culture and the whole genome was sequenced by next generation sequencing. Phylogenetic analysis, similarity comparison and recombination analysis were conducted via MEGA 7.0.26, BioEdit 7.0.9.0 and Simplot 3.5.1.Results:A PSV strain 265/SD was isolated from Culex tritaeniorhynchus. The clear cytopathic effects characterized by rounding, shrinkage and detachment of cells were observed on BHK21 cells. The whole genome of this study strain was 7 558 nt in length. Phylogenetic analysis based on VP1 sequences indicated that strain 265/SD belonged to traditional genotype. Different positions of 265/SD in the VP1 and 3D phylogenetic trees suggested the recombinant potential. Similarity plot revealed the existence of recombination but the exact origins remained unknown. The similarity analysis of VP1 regions showed that strain 265/SD had low nucleotide identity (77.3%) and amino acid identity (80.3%) with another strain SD/CHN/2016 from Shandong province. Conclusions:Our data enriched the whole genome information of PSV in Shandong province and provided scientific basis for prevention and control of PSV.

Objective:The investigation and research on the application status of Hepatic Venous Pressure Gradient (HVPG) is very important to understand the real situation and future development of this technology in China.Methods:This study comprehensively investigated the basic situation of HVPG technology in China, including hospital distribution, hospital level, annual number of cases, catheters used, average cost, indications and existing problems.Results:According to the survey, there were 70 hospitals in China carrying out HVPG technology in 2021, distributed in 28 provinces (autonomous regions and municipalities directly under the central Government). A total of 4 398 cases of HVPG were performed in all the surveyed hospitals in 2021, of which 2 291 cases (52.1%) were tested by HVPG alone. The average cost of HVPG detection was (5 617.2±2 079.4) yuan. 96.3% of the teams completed HVPG detection with balloon method, and most of the teams used thrombectomy balloon catheter (80.3%).Conclusion:Through this investigation, the status of domestic clinical application of HVPG has been clarified, and it has been confirmed that many domestic medical institutions have mastered this technology, but it still needs to continue to promote and popularize HVPG technology in the future.

Objective:To explore newer enteroviruses (EVs) circulating in China and research their genetic characterization.Methods:Sewage samples were collected in Jinan in January and July of 2018, respectively. PCR amplification of the P1 coding region of EV and next-generation sequencing (NGS) were conducted. Homologous and phylogenetic analyses were performed on the newly identified newer EVs.Results:The EV-A89 (n=2) and EV-C96 (n=1) nucleic acid sequences were detected in the sewage in January and July, respectively and obtained complete P1 coding sequence. The two EV-A89 sequences had 6.1% nucleotide divergence among themselves, and had 88.2%-95.3% homologies with other strains. No close genetic relationship was obtained with the sequences from Xinjiang, China and those from other countries. The EV-C96 sequence in this study had 76.2%-89.4% nucleotide similarities with other isolates throughout the world. Phylogenetic analysis showed that global EV-C96 strains were divided into 5 branches, i. e, A to E. Except for the Shandong 1991 isolate, the other Shandong and domestic strains were all located in branch D.Conclusions:This study added the molecular epidemiologic data of newer enteroviruses EV-A89 and EV-C96, and provides basic data for future research on the epidemic trend of EV-A89 and EV-C96 as well as their association with diseases.

Objective:To establish virus culture method and full genome sequencing method for severe acute respiratory syndrome coronavirus (2019-nCoV), and to illuminate the variation of 2019-nCoV.Methods:The pharyngeal swab specimens were inoculated into Vero-E6 cells for isolation, and the cytopathic effect were observed day by day, and the result of virus isolation were confirmed by Real-Time RT-PCR. Some isolated viruses were diluted 10 times to detect the virus titer. Full-genome of 2019-nCoV was sequenced with the whole genome capture technology and next generation sequencing technology. Phylogenetic analysis and molecular characterization for obtained 2019-nCoV sequences were undertaken.Results:Twenty-two 2019-nCoV strains were isolated with Vero-E6 cell line in the Biosafety Level-3 Laboratory (BSL-3). Eighteen full-genome sequences obtained (almost 29 000 nucleotide) were analyzed with 99.94%~100% identity and 28 nucleotides and 20 amino acids variations. Phylogenetic analysis showed that the 2019-nCoV sequences belonged to different clades, including clade S and clade L with Europe lineage L. I and Europe lineage L. II.1. Furthermore, 5 of 18 2019-nCoV harbor the D614G mutation.Conclusions:2019-nCoV were successfully isolated with Vero-E6 cells, and partially illuminated the phylogenetic characteristics, which provided a basis for subsequent drug screening and biological characteristics research. Continuous monitoring and analysis of the sequences of new cases would be vital to understand the genetic evolution and rates of substitution of the 2019-nCoV.

Rotaviruses infection is one of the main causes of diarrhea among infants and children in the world, resulting in rotavirus gastroenteritis, which is very harmful and has caused a huge disease burden and no specific drug treatment. This paper reviews the rotavirus etiology, epidemiological characteristics, disease burden of rotavirus gastroenteritis and rotavirus vaccines. RV in group A is the main cause of acute gastroenteritis in infants, people at all ages are generally susceptible to RV, 3 to 24 months infants have the most severe symptoms of diarrhea, RVGE epidemic is seasonal and peaks in winter, increasing RV vaccination can reduce the incidence and mortality of rotavirus diarrhea in infants to reduce the burden of corresponding disease. This article focuses on RV vaccines currently in use and their effect on preventing RV infection, and put forward thoughts and suggestions on technical issues related to the application of RV vaccine in China. Provide support for improving the RV vaccine immunization strategy and Chinese-specific immunization strategy for eventually incorporating RV vaccine into the national child immunization program.

Objective:To understand the detection of group A rotavirus (RVA) in domestic sewage and its molecular epidemiological characteristics, and further explore the feasibility and necessity of RVA environmental surveillance.Methods:From 2016 to 2018, we collected domestic sewage samples monthly in Jinan city, and concentrated them via anion membrane adsorption-elution method. Then RNA extraction and RVA VP7 and VP4 coding region RT-PCR amplification were performed. After purification, TA cloning and sequencing, homology analysis and phylogenetic analysis were conducted on the obtained sequences.Results:RVA G gene was detected in 31 of the 36 sewage samples (86.1% detection rate); RVA P genotype was detected in 33 samples (91.7% detection rate). A total of 536 RVA sequences were obtained, of which 225 G-type sequences belonged to 6 genotypes, and the G9 accounted for 92.4% (208/225); 311 P-type sequences were obtained, which belonged to 4 genotypes. The dominant P[8] accounted for 50.1% (156/311), followed by P[4] with 41.8% (130/311). Phylogenetic analysis shows that there were multiple transmission chains circulating in the dominant genotypes G9 and P[8].Conclusion:The genotype, homology, and phylogenetic characteristics of sequences obtained from domestic sewage in Jinan area were described, which further confirmeing that RVA environmental surveillance is not feasible but also necessary.