Objective:To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023.Methods:The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed.Results:A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M ( Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant ( P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age ( P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion:Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

Objective:To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023.Methods:The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed.Results:A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M ( Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant ( P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age ( P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion:Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

Objective:To understanded the pathogen spectrum and epidemiological characteristics of common respiratory viruses in hospitalized patients with severe acute respiratory infection (SARI) in Lanzhou, in order to provide a reference for the prevention, control and treatment of SARI cases in Lanzhou.Methods:From January 2011 to December 2020, 2 571 samples including throat swabs, sputum and a small amount of alveolar lavage fluid from SARI cases in the First Hospital of Lanzhou University, and data and clinical information were collected at the same time, the monitored population was divided into 5 age groups (0 year-, 1 year-, 5 years-, 15 years-, 60 years-), and the nucleic acid detection of common respiratory viruses was performed by multiplex real-time PCR.Results:A total of 9 viruses were detected in 2 571 samples, with a total positive rate of 24.66%. Among them, the top 4 viruses were respiratory syncytial virus (8.71%), rhinovirus (4.60%), influenza virus (4.40%), and parainfluenza virus (3.85%). The 0 year-group had the highest proportion of infants (36.37%), the highest positive detection rate (26.95%), the highest detection rate of respiratory syncytial virus (13.05%) were found in this group, and in the 5 years-group rhinovirus detection rate was the highest (6.13%). The 15 years-group and 60 years- group had the highest detection rates of influenza virus, which were 9.75% and 6.35%. The difference in positive detection rate between different age groups was statistically significant( χ2=12.11, P=0.038). The peak incidence was in winter and spring every year. Conclusions:The virus with the highest infection rate of SARI cases in Lanzhou was respiratory syncytial virus. Different age groups have different dominant viruses. Winter and spring are the epidemic seasons.

Objective:To analyze the antigenicity and genetic characteristics of two strains of Eurasian avian H1N1 swine influenza virus (EAS-H1N1) isolated from 2 human cases found in Gansu province to provide scientific reference for disease prevention and control.Methods:Two cases of human infection with EAS-H1N1 discovered in Gansu province since February 2021 were analyzed for antigenicity and genome comparison, and their genome characteristics were analyzed using software such as Mega7.0.Results:Two human infections with EAS-H1N1 had related environmental exposure history. Two strains were obtained: A/Gansu-Xifeng/1143/2021 and A/Gansu-Xifeng/1194/2021. The two strains of HA, NA genes were all from the Eurasian avian H1N1 swine influenza virus, and are closely related to the human infection EAS-H1N1 virus in Hebei and Tianjin and the EAS-H1N1 virus isolated from the mink in Shandong; the HA receptor binding sites of 2 strains E190D and D225E mutations occurred in all spots, and there were no H274Y and N294S mutations in NA protein.Conclusions:Some important molecular mutations occurred in the genome of people infected with EAS-H1N1 virus in Gansu province, which may lead to increased virulence and potential human-to-human transmission. Strengthening the research and analysis of EAS-H1N1 gene characteristics will help to monitor the mutation and mutation of the virus at the molecular level and scientifically prevent and control the epidemic.

Objective:To disclose the genome characteristics and mutations of 2019 novel coronavirus (2019-nCoV) strains from the imported cases of Coronavirus Disease 2019 (COVID-19) in Gansu province, thereby to provide scientific reference for the prevention and control of COVID-19 in Gansu province. Methods:The respiratory tract specimens of imported COVID-19 cases from seven countries in Gansu province in 2020 were collected. The virus genome was sequenced by the second-generation sequencing technology, the whole genome sequences were compared and analyzed, and the MEGA software was used to construct a phylogenetic tree based on the neighbor-joining method.Results:A total of 46 2019-nCoV genome sequences with a length of 29 605~29 903 bp were obtained. Compared with the Wuhan reference strain (GenBank ID: NC_045512.2), it was found that the median (minimum to maximum) number of the nucleotide mutations of the 2019-nCoV genome sequence of the imported cases was 10 (7-24). A total of 134 nucleotide mutation sites were found in all 2019-nCoV genome sequences from 7 entry countries in Gansu province, distributed in 11 open reading frames (ORFs). The top three nucleotide mutations in different proteins: ORF1ab (78), S(20), N(12). Among the 134 nucleotide mutations, 82 caused amino acid mutations, and all of them were missense mutations. No insertions or deletions were seen. Types of deletion mutations, the top three amino acid mutations in different proteins: ORF1ab (46), S(11), N(10); the key sites of the receptor binding domain (RBD) of the S protein have not been mutated.Conclusions:No imported cases in Gansu province have been found to carry the reported mutations that can clearly lead to changes in the spread and pathogenicity of 2019-nCoV.

Objective:To study the epidemic and etiologic characteristics of influenza virus(Flu)and respiratory syncytial virus (RSV) infections in outpatient influenza-like illness(ILI)cases of children under 10 years of age in Gansu province in 2018 And to provide evidences for diagnosis, treatment, control and prevention of Flu and RSV infections in Gansu province.Methods:A total of 8 559 pharyngeal swab samples of ILI outpatients cases were tested with real-time fluorescent PCR to detect Flu, 3 436 of which were detected by RT-PCR for RSV.Results:Of the 8559 specimens, 934 (10.91%) samples were positive for Flu. Among them, 431 were positive for H1N1, 70 were positive for H3N2, 428 were positive for Flu B, 5 were mixed; 320 of the 3436 (9.31%, ) samples were positive for RSV. There were significant differences in the positive rates of Flu and RSV among 14 cities and prefectures ( χ2=56.99, χ2=263.34, Р< 0.01). Influenza reached its peak in January 2018 with a positive rate of 50.70%. Flu B/Yamagata strain (53.53%) and A H1N1 (39.93%) were prevalent simultaneously. The peak of RSV epidemic was from February to April, the positive rate was 13.98%. The RSV positive rate of children under 5 years of age was 10.11%, higher than that of children over 5 years of age was 6.94%. There was statistical significance ( χ2=7.67, Р<0.01). Conclusions:RSV and influenza viruses are the main pathogens in ILI cases of children under 10 years of age. There are epidemic peaks in winter and spring every year. It is suggested that the monitoring of RSV and the development and application of vaccine should be strengthened.

Objective:To analyze the influenza surveillance results and epidemiological characteristics of the disease in Gansu province in 2010-2018, and provide scientific basis for the formulation and adjustment of influenza prevention and control strategies.Methods:Real-time PCR was used to detect the specimens of ILI illness (ILI) cases reported by 19 national influenza surveillance sentinel hospitals in Gansu province. Influenza virus isolation and culture were carried out using canine kidney cells (MDCK).Results:Total of 93 334 specimens from ILI cases were collected from Jan. 2010 to Dec. 2018, and 13 439 samples were positive for influenza virus nucleic acid. The positive rate of viral nucleic acid detection was 14.40%, and the proportion of influenza B virus in positive samples was the highest (37.02%), and seasonal H3N2 influenza virus (35.25%), H1N1 influenza virus (26.78%). The advantages are different in various periods. The peak period of influenza is from Dec. to Mar., and the highest incidence rate is in the age group of 5-15 years (20.34%). The incidence rates of the other age groups are similar. The difference of influenza positive rate in different age groups is statistically significant ( χ2=775.153, P<0.001), but in male and female was not significant. Total of 16 101 ILI specimens positive for influenza virus nucleic acid were subjected to virus isolation and cultured, and 3 892 strains of influenza virus were isolated, of which influenza B virus accounted for the highest proportion (37.82%), followed by seasonal H3N2 influenza virus (33.04%), H1N1 influenza virus (28.96%). Conclusions:The epidemic of influenza in Gansu province had an obvious regularity, and it was undulating and prevalent. It is necessary to strengthen prevention and control measures among school-age children and adolescents.

Objective:To analyze the epidemiological characteristics of the first case of human infection with H7N9 avian influenza in Gansu province, and to provide scientific basis for the prevention and control of H7N9 avian influenza.Methods:The epidemiological investigation method was used to investigate the incidence and treatment, possible infection sources, transmission routes and exposure factors of the first human case of H7N9 infection in Gansu province, medical investigation was also conducted for close contacts, and external environmental samples were collected for detection. Moreover, we initiated disinfection of the epidemic area.Results:The first case of human infection with H7N9 avian influenza confirmed in Gansu province was an 82-year-old male urban resident. He went to a private clinic for cough on March 29, and went to Jiuquan City Hospital on April 3 for treatment. The patient had a history of activities near the live poultry sales store where H7N9 virus nucleic acid was tested positive, The positive test result of H7N9 avian influenza virus nucleic acid detected from pharynx swab was consistent with those of the Provincial and National Centers for Disease Control and Prevention. The case was carefully treated and cured 17 days after the onset. Nine close contacts underwent a 7 days medical health observation, which did not show any health abnormalities. A total of 357 flu-like cases and unexplained pneumonia and 2 cases who were H7N9 avian influenza virus nucleic acid positive were reported in the city. Three cases of H7N9 found in Jiuquan city had a history of exposure to the live poultry market, and one of them died due to late diagnosis.Conclusions:Exposure to the external environment of H7N9 avian influenza virus is the main risk factor of H7N9 infection in humans. The management of free-range poultry and live poultry market should be strengthened, especially the circulation management of live poultry. The monitoring of external environment for avian influenza plays an important role in the prevention and control of human infection with h7n9 avian influenza.

Objective:To analyze the genomic characteristics of human infection with H9N2 avian influenza virus in Gansu province.Methods:The etiological analysis was conducted for human infection with H9N2 avian influenza virus detected in influenza like illness cases in northwestern China in 2016. Molecular bioinformatics Mega 7.0 software was used to analyze the full genomic sequences of the viral isolate.Results:The gene fragments of HA, NA, MP, NP, NS, PA, PB1 and PB2 of the isolate were highly similar (>90%) to those of H9N2 avian influenza virus strain isolated in external environment in Gansu from 2014 to 2019. The HA gene belonged to BJ/94-like branch, PB2 and MP belonged to G1/97-like branch, and the PB1, PA, NS, and NP genes belonged to F/98-like branch. MP and PB2 were closely related to H7N9, H10N8 and H5N6 viruses. Amino acid sequence alignment showed that the HA cleavage site was arranged in PSRSSR ↓ GLF, H183N and Q226L mutated which included 7 HA glycosylated sites; 62-64 sites of NA absented 3 amino acids (ITE); and M2-31N, NS1-42S, PA-356R, and PA-409N mutated.Conclusions:Apparently, this case of human infection with human infection with H9N2 avian influenza virus was an incidental. However, the isolates of H9N2 influenza virus in external environment of Gansu had a series of mammalian adaptive molecular markers, suggesting that the risk of human infection is higher. It is necessary to strengthen the surveillance by multi departments to deal with influenza pandemic.

Objective:To understand the characteristics and differences of diarrhea-related symptoms caused by different pathogens, and the clinical features of various pathogens causing diarrhea.Methods:Etiology surveillance program was conducted among 20 provinces of China from 2010 to 2016. The acute diarrhea outpatients were collected from clinics or hospitals. A questionnaire was used to survey demographics and clinical features. VFeces samples were taken for laboratory detection of 22 common diarrhea pathogens, to detect and analyze the clinical symptom pattern characteristics of the patient’s.Results:A total of 38 950 outpatients were enrolled from 20 provinces of China. The positive rates of Rotavirus and Norovirus were the highest among the five diarrhea-causing viruses (Rotavirus: 18.29%, Norovirus: 13.06%). In the isolation and culture of 17 diarrhea-causing bacterial, Escherichia coli showed the highest positive rates (6.25%). The clinical features of bacterial diarrhea and viral diarrhea were mainly reflected in the results of fecal traits and routine examination, but pathogenic Vibrio infection was similar to viral diarrhea. Conclusion:Infectious diarrhea presents different characteristics due to various symptoms which can provide a basis for clinical diagnosis.