Objective:To analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024.Methods:The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis, drug susceptibility test, gene sequencing and evolutionary analysis.Results:From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49 th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) subtype strain did not have a high matching effect with the 2023-2024 vaccine strain and had a long evolutionary distance, but had a close evolutionary distance with the 2024-2025 vaccine strain. Drug susceptibility test showed that oseltamivir sensitivity of influenza A(H1N1)pdm09 strain decreased greatly, and the amino acid site mutation of neuraminidase was H275Y. Conclusions:In the 2023-2024 surveillance year, the peak of influenza virus epidemic in Shandong was mainly occurred in winter and spring, and the age group of 5-14 years was the focus of prevention and control. The dominant strain was subtype A(H3N2), which had poor matching effect with the vaccine strain in the 2023-2024 surveillance year. One A(H1N1)pdm09 resistant strain was found in the drug resistance monitoring work. Follow-up prevention and control work should be strengthen the surveillance for the epidemiological characteristics, genetic variation and drug resistance of influenza viruses, timely understand the epidemic trend and mutation of influenza viruses, timely discover drug-resistant strains of influenza viruses, promote influenza vaccination, and improve of influenza prevention and control.

Objective:To deeply analyze the epidemiological characteristics and changing trends of intestinal infectious diseases in China, and provide scientific evidence for the prevention and control of intestinal infectious diseases.Methods:The incidence data of notifiable intestinal infectious diseases in China from 2013 to 2022 were collected from China Disease Prevention and Control Information System. Descriptive statistical method was used to analyze the distributions of intestinal infectious diseases in China, and the annual change rate and seasonal index were calculated.Results:During 2013-2022, intestinal infectious diseases were reported nationwide, with the cases accounting for 43.50% of all notifiable infectious disease cases. The average reported incidence rate was 224.50/100 000, showing a decreasing trend year by year (average annual percent change=-6.45%, t=-2.76, P=0.025). The top 5 intestinal infectious diseases were hand foot and mouth disease (HFMD) (130.40/100 000), other infectious diarrhea (80.18/100 000), dysentery (7.45/100 000), acute hemorrhagic conjunctivitis (2.49/100 000) and viral hepatitis E (1.92/100 000). The incidences of dysentery, HFMD, typhoid fever/paratyphoid fever, viral hepatitis A and acute hemorrhagic conjunctivitis all showed decreasing trends year by year (all P<0.05), while the incidences of hepatitis E and other infectious diarrhea showed no significant changes with year (both P>0.05). The incidence of intestinal infectious diseases was high during May to October, with the peak in June. The incidence rate of intestinal infectious diseases was significantly higher in men than in women (all P<0.05). The HFMD, other infectious diarrhea and dysentery cases were mainly children aged 0-5 years, while the cholera, hepatitis A, hepatitis E, typhoid fever/paratyphoid fever and acute hemorrhagic conjunctivitis cases were mainly farmers aged ≥20 years. The annual reported incidence rate of intestinal infectious diseases was higher in southern provinces (283.66/100 000) than in northern provinces (142.63/100 000), and the annual reported incidence rate of intestinal infectious diseases was higher in coastal provinces (279.52/100 000) than in inland provinces (181.78/100 000), the differences were all significant (both P<0.001). Conclusions:During 2013-2022, the incidence of intestinal infectious diseases decreased significantly in China, with HFMD and other infectious diarrhea as the main diseases. Strengthened surveillance for intestinal infectious diseases should be carried out in key groups, such as children living scatteredly and farmers, and targeted prevention and control measures should be taken according to the epidemiological characteristics of different diseases to effectively reduce the incidence of intestinal infectious diseases.

Objective:To analyze the situation of rodents carrying Hantavirus and the genetic and evolutionary characteristics of the virus in Zibo city, Shandong province in 2022, and provide reference for the scientific prevention and control of hemorrhagic fever with renal syndrome (HFRS).Methods:Real-time quantitative PCR (RT-qPCR) was used to detect hantavirus (HV) nucleic acids in rodent lung tissues and identify HV genotypes. Each nucleic acid fragment was designed to amplify various gene fragments by segment, and the whole genome of Hantavirus was sequenced by second generation sequencing. Sequence assembly was performed using SeqMan 7.1.0.44, a subprogram of DNAStar. Sequence alignment and evolutionary analysis were conducted using MEGA 7.0 and BioEdit software.Results:A total of 270 host animals were captured in this survey. Among them, 13 rodent lung samples tested positive for Hantavirus, resulting in a virus-positive rate of 4.8%. The full-genome sequences of four hantavirus strains were successfully obtained, all identified as Seoul virus (SEOV) genotype. Four Hantavirus-positive samples showed high nucleotide sequence homology in the M gene and belonged to the SEOV S3 subtype. These strains exhibited high similarity with those from Hebei, Liaoning, and Beijing. The amino acid sequences of the nucleoprotein and glycoprotein immunogenic epitopes were identical to those of the vaccine strain Z37.Conclusions:This study successfully determined the full genome sequences of four hantavirus strains from Zibo city, Shandong province. The genotypes are primarily SEOV, with the subtype being S3. The homology of genes within the same subtype is high, with no significant variations observed. The alignment of immune epitopes in key proteins suggests that the current vaccine may provide protection against locally circulating strains, but further in-depth research is still required.

Objective:To understand the epidemiological characteristics of severe fever with thrombocytopenia syndrome (SFTS) in Shandong province from 2010 to 2022, analyze the trends in morbidity and mortality, and provide a scientific basis for the prevention, control, diagnosis, and treatment of SFTS.Methods:The data on SFTS cases and deaths were retrospectively collected through the China Disease Control and Prevention Information System′s infectious disease surveillance system and the Shandong province all-cause mortality surveillance system. Descriptive epidemiological method was used for epidemiological analysis, and the Joinpoint regression model was applied to analyze trends in morbidity and mortality.Results:From 2010 to 2022, 6 714 SFTS cases were reported in Shandong, with an average crude incidence rate (CIR) and age-standardized incidence rate (ASIR) of 0.52/100 000 and 0.43/100 000, respectively. Among these, 1, 064 cases died within 30 days of onset, with an average crude mortality rate (CMR) and age-standardized mortality rate (ASMR) of 0.08/100, 000 and 0.06/100 000, respectively, and an average case fatality rate of 15.85%. The average incidence rates for males and females were 0.52/100 000 and 0.53/100 000, respectively, with no statistically significant difference ( P>0.05). The average annual mortality rate for males (0.09/100 000) was higher than that for females (0.08/100 000), and the average annual case fatality rate for males (17.21%) was higher than that for females (14.48%), with statistically significant differences ( P<0.05); 93.95% of the cases were over 45 years old, and 86.56% of the deaths were over 60 years old. Both cases and deaths were primarily among farmers, accounting for over 85% of the total. From 2010 to 2022, the incidence rate of SFTS in Shandong showed an overall upward trend, with an average annual percentage change (AAPC) in CIR of 23.58% and an AAPC in ASIR of 19.97%, P<0.05. The mortality rate of SFTS cases in Shandong from 2010 to 2022 showed a continuous and significant upward trend, with a CMR AAPC of 27.64% and an ASMR AAPC of 22.70%, P<0.05. SFTS incidence and mortality in Shandong exhibited clear seasonality, with high occurrence from May to October, primarily concentrated in the Jiaodong Peninsula and the hilly areas of central Shandong. The number of affected counties increased in a wave-like pattern, expanding from 6 in 2010 to 79 in 2021 for cases and from 2 in 2010 to 53 in 2022 for deaths. Conclusions:From 2010 to 2022, the incidence and mortality of SFTS in Shandong showed an upward and expanding trend, with a particularly heavy disease burden among middle-aged and elderly farmers.

Objective:To analyze the respiratory virus infection status and epidemiological characteristics of influenza-like illness (ILI) cases in Shandong Province during the 2020 -2021 influenza surveillance year. Methods:According to the National Influenza Surveillance Plan (2017 version), throat swab samples of ILI cases were collected from 14 surveillance sentinel hospitals in Shandong Province. Nucleic acid was extracted from all samples. Real-time fluorescence quantitative PCR (RT-PCR) was utilized to detect six common viruses, including human metapneumovirus (HMPV), human parainfluenza virus (HPIV) types 1, 2 and 3, respiratory syncytial virus (RSV), and adenovirus (ADV). Subsequently, the obtained detection results were analyzed.Results:A total of 2 386 specimens were collected, with a detection rate of 24.22% (578). Six viruses were detected, with detection rates of 6.75% (162 cases) for HMPV, 5.87% (140 cases) for RSV, 3.56% (85 cases) for HPIV3, 3.14% (75 cases) for HPIV2, 2.98% (71 cases) for HPIV1, and 2.77% (66 cases) for ADV. There was no significant difference in detection rates between genders, but a notable variation among different age groups ( P<0.001). The highest detection rate was observed in individuals aged 0-4 years (31.94%), followed by those aged≥60 years (26.06%). The prevalence of six viruses showed a monthly variation, with the detection rate of HMPV being higher in December and HPIV1 being higher in February. HPIV2, HPIV3, RSV, and ADV had higher detection rates in November. The co-detection rate of multiple viruses was 0.80%, with RSV being the most common pathogen involved in co-detection, primarily in individuals aged 0-4 years. Conclusion:The detection of six multiple pathogens in ILI cases in Shandong Province is dominated by HMPV, RSV and HPIV3. The prevalence of respiratory viruses varies by age and time.

Objective:To investigate the drug resistance gene characteristics, plasmid characteristics and genome tracing of Shigella sonnei causing a bacillary dysentery outbreak in Shandong Province. Methods:Sixty-five Shigella sonnei strains isolated from a 2021 outbreak in a county of Shandong Province were analyzed using antimicrobial susceptibility testing, whole genome sequencing (WGS), characterization of resistance and virulence genes, plasmid profiling, core genome multilocus sequence typing (cgMLST), and single nucleotide polymorphism (SNP) analysis. Results:All isolates had the same resistance phenotype and genotypes and were multidrug-resistant ESBL-producing Shigella sonnei, carrying important virulence genes. Plasmid analysis revealed a conserved genetic arrangement, pil( M/ N/ O2/ P)-tra( F/ H/ J/ K/ N/ O/ P/ Q)-IS Ecp1- blaCTX-M-14-Tn 903- yub( J/ I/ F/ G/ E/ D), and shared across strains from diverse regions and bacterial species. The cgMLST and SNP analyses demonstrated concordant clustering, with all 65 outbreak-related strains forming a single cluster alongside human-derived strains from Guangxi. Conclusion:The ESBL-producing Shigella sonnei responsible for the outbreak shares a homologous relationship with Guangxi human-derived strains, and the detected resistance plasmids and virulence genes underscore the need to strengthen drug resistance surveillance and genome tracing.

This study investigated the epidemic status of H3N2 influenza virus and the genetic evolution characteristics of hemagglutinin(HA)and neuraminidase(NA)of H3N2 subtype influenza viruses isolated in Shandong Province during 2023-2024,to understand their compatibility with vaccine strains and drug resistance status.A total of 25 H3N2 subtype influenza virus strains were randomly selected from the strains isolated by the influenza surveillance network laboratory.The HA and NA genes were sequenced with the vaccine strains recommended by the WHO as a reference.Monitoring of sensitivity to oseltamivir and zanamivir was conducted through neuraminidase inhibition experiments.The H3N2 influenza viruses in Shandong Province belonged to the 3C.2a1b.2a.2a.3a.1 clade.Nucleotide sequence analysis revealed that the HA1 and NA genes were closely related to the WHO-recommended vaccine strain A/Darwin/9/2021 for the current season,with homology rates of 97.8%-98.2%and 98.9%-99.3%,respectively.Amino acid sequence analysis indicated 22 amino acid sequence variations in the HA1 protein,and antigenic drift was detected in 8 strains.A glycosylation site was added at position 94 of the HA protein in all 25 strains.Variations occurred in the NA antigenic determinants of some strains.Neuraminidase inhibition experiments indicated that all tested influenza viruses were sensitive to oseltamivir and zanamivir.Some differences in HA and NA proteins were observed between the monitored strains and vaccine strains.Continued monitoring of the molecular evolution characteristics of influenza viruses is necessary to understand the risk of influenza outbreaks,and their effects on the effectiveness of influenza vaccines and therapeutic drugs.

Objective:To analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024.Methods:The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis, drug susceptibility test, gene sequencing and evolutionary analysis.Results:From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49 th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) subtype strain did not have a high matching effect with the 2023-2024 vaccine strain and had a long evolutionary distance, but had a close evolutionary distance with the 2024-2025 vaccine strain. Drug susceptibility test showed that oseltamivir sensitivity of influenza A(H1N1)pdm09 strain decreased greatly, and the amino acid site mutation of neuraminidase was H275Y. Conclusions:In the 2023-2024 surveillance year, the peak of influenza virus epidemic in Shandong was mainly occurred in winter and spring, and the age group of 5-14 years was the focus of prevention and control. The dominant strain was subtype A(H3N2), which had poor matching effect with the vaccine strain in the 2023-2024 surveillance year. One A(H1N1)pdm09 resistant strain was found in the drug resistance monitoring work. Follow-up prevention and control work should be strengthen the surveillance for the epidemiological characteristics, genetic variation and drug resistance of influenza viruses, timely understand the epidemic trend and mutation of influenza viruses, timely discover drug-resistant strains of influenza viruses, promote influenza vaccination, and improve of influenza prevention and control.

Objective:To deeply analyze the epidemiological characteristics and changing trends of intestinal infectious diseases in China, and provide scientific evidence for the prevention and control of intestinal infectious diseases.Methods:The incidence data of notifiable intestinal infectious diseases in China from 2013 to 2022 were collected from China Disease Prevention and Control Information System. Descriptive statistical method was used to analyze the distributions of intestinal infectious diseases in China, and the annual change rate and seasonal index were calculated.Results:During 2013-2022, intestinal infectious diseases were reported nationwide, with the cases accounting for 43.50% of all notifiable infectious disease cases. The average reported incidence rate was 224.50/100 000, showing a decreasing trend year by year (average annual percent change=-6.45%, t=-2.76, P=0.025). The top 5 intestinal infectious diseases were hand foot and mouth disease (HFMD) (130.40/100 000), other infectious diarrhea (80.18/100 000), dysentery (7.45/100 000), acute hemorrhagic conjunctivitis (2.49/100 000) and viral hepatitis E (1.92/100 000). The incidences of dysentery, HFMD, typhoid fever/paratyphoid fever, viral hepatitis A and acute hemorrhagic conjunctivitis all showed decreasing trends year by year (all P<0.05), while the incidences of hepatitis E and other infectious diarrhea showed no significant changes with year (both P>0.05). The incidence of intestinal infectious diseases was high during May to October, with the peak in June. The incidence rate of intestinal infectious diseases was significantly higher in men than in women (all P<0.05). The HFMD, other infectious diarrhea and dysentery cases were mainly children aged 0-5 years, while the cholera, hepatitis A, hepatitis E, typhoid fever/paratyphoid fever and acute hemorrhagic conjunctivitis cases were mainly farmers aged ≥20 years. The annual reported incidence rate of intestinal infectious diseases was higher in southern provinces (283.66/100 000) than in northern provinces (142.63/100 000), and the annual reported incidence rate of intestinal infectious diseases was higher in coastal provinces (279.52/100 000) than in inland provinces (181.78/100 000), the differences were all significant (both P<0.001). Conclusions:During 2013-2022, the incidence of intestinal infectious diseases decreased significantly in China, with HFMD and other infectious diarrhea as the main diseases. Strengthened surveillance for intestinal infectious diseases should be carried out in key groups, such as children living scatteredly and farmers, and targeted prevention and control measures should be taken according to the epidemiological characteristics of different diseases to effectively reduce the incidence of intestinal infectious diseases.

This study investigated the epidemic status of H3N2 influenza virus and the genetic evolution characteristics of hemagglutinin(HA)and neuraminidase(NA)of H3N2 subtype influenza viruses isolated in Shandong Province during 2023-2024,to understand their compatibility with vaccine strains and drug resistance status.A total of 25 H3N2 subtype influenza virus strains were randomly selected from the strains isolated by the influenza surveillance network laboratory.The HA and NA genes were sequenced with the vaccine strains recommended by the WHO as a reference.Monitoring of sensitivity to oseltamivir and zanamivir was conducted through neuraminidase inhibition experiments.The H3N2 influenza viruses in Shandong Province belonged to the 3C.2a1b.2a.2a.3a.1 clade.Nucleotide sequence analysis revealed that the HA1 and NA genes were closely related to the WHO-recommended vaccine strain A/Darwin/9/2021 for the current season,with homology rates of 97.8%-98.2%and 98.9%-99.3%,respectively.Amino acid sequence analysis indicated 22 amino acid sequence variations in the HA1 protein,and antigenic drift was detected in 8 strains.A glycosylation site was added at position 94 of the HA protein in all 25 strains.Variations occurred in the NA antigenic determinants of some strains.Neuraminidase inhibition experiments indicated that all tested influenza viruses were sensitive to oseltamivir and zanamivir.Some differences in HA and NA proteins were observed between the monitored strains and vaccine strains.Continued monitoring of the molecular evolution characteristics of influenza viruses is necessary to understand the risk of influenza outbreaks,and their effects on the effectiveness of influenza vaccines and therapeutic drugs.