Abstract: Objective To analyze the epidemiological characteristics of viral hepatitis E in Fujian Province from 2012-2021, and to provide scientific evidence for the prevention and control of hepatitis E in the future. Methods Descriptive epidemiological method was used to analyze hepatitis E cases in Fujian Province from 2012 to 2021. Results From 2012 to 2021, a total of 8 877 cases of hepatitis E were reported in Fujian Province from 2012-2021. The overall incidence rate showed a decreasing trend (χ2trend =458.14, P<0.001), with the lowest incidence rate of 1.32/100 000 in 2020 and an annual average incidence rate of 2.29/100 000 per year. The incidence was higher in winter and spring, with the months of March and April having the highest number of reported cases (2 146, 24.17%) and the fewest cases were reported in September (571, 6.43%). The difference in reported incidence rates between cities was statistically significant (χ2=1 877.75, P<0.01). The comprehensive experimental zone of Pingtan had the highest average reported incidence rate of 6.03/100 000, while Zhangzhou had the lowest at 0.94/100 000. The number of male cases was higher than the number of female cases, with a male to female ratio of 2.04∶1. The disease was most prevalent among middle-aged and elderly individuals, with the age group of 40-<65 years having the highest number of reported cases, accounting for 57.44% (5 099/8 877) of all cases. The age group of 50-<55 years had the highest reported incidence, with the number of reported cases increasing with age below 50 years, but decreasing with age over 50 years. As for occupational distribution, peasants had the highest proportion of the disease, accounting for 34.49% (3 062 cases) of the total cases. Conclusions The reported incidence rate of hepatitis E in Fujian showed a downward from 2012 to 2021. Due to the impact of COVID-19, incidence of the lowest was 2020, but it did not reflect the true situation of the disease, which may have affected trend of hepatitis E. In order to control and reduce the incidence of hepatitis E, efforts should be made to increase publicity and education on health knowledge and vaccination among key areas and populations, strengthen monitoring and diagnostic capability, and implement comprehensive prevention and control measures.

Objective:To understand the genome characteristics of group A rotavirus (RVA) strains among hospitalized children under 5 years of age with acute diarrhea in Fuzhou sentinel hospital in 2020.Methods:The ELISA method was used for screening RVA-positive stool samples of hospitalized children under 5 years of age, then 11 gene segments of RVA-positive samples were sequenced and typed after amplification by RT-PCR, and their homology and phylogenetic analysis were performed by Molecular Evolutionary Genetics Analysis (MEGA).Results:Twenty RVA whole genome sequences were successfully obtained, including 4 kinds of G/P gene combinations-G9P[8] (55%), G3P[8] (25%), G8P[8] (15%) and G2P[4] (5%). DS-1-like reassortant strains accounted for 40% of the whole genomes. Strains of the same type have high sequence homology, are closely related to the virus strains that currently circulating in the world. There are mutations at multiple important antigenic sites on VP7, VP4 and NSP4 fragments. The variation of amino acid substitutions of VP7, VP4 and NSP4 fragments is complicated, and there are many amino acid substitutions in the antigenic regions.Conclusions:G3P[8] and G8P[8] DS-1-like reassortants were detected for the first time in Fuzhou, amino acid substitutions were observed in the antigenic regions of the VP7, VP4 and NSP4 gene. Due to the emergence of uncommon DS-1-like reassortant strains and multiple important antigenic regions substitutions, it is necessary to continuously monitoring genome characteristics of RVA strains to provide scientific evidence for the pandemic prevention and vaccine immunization strategies.

Objective:To identify the viral etiologies and epidemic characteristics of acute respiratory infection (ARI) in Fuzhou.Methods:The information and respiratory tract specimens of ARI cases from three different types of hospitals in Fuzhou were collected in 2019. Real-time quantitative fluorescent PCR (Polymerase Chain Reaction, PCR) was uesd to detect adenovirus (AdV) and human bocavirus (HBoV), Real-time quantitative fluorescent RT-PCR (Reverse Transcription-PCR, RT-PCR) was used to detect influenza virus A/B (IFV-A/B), respiratory syncytial virus (RSV), parainfluenza virus 1-4 (PIV-1~4), human metapneumovirus (HmpV), coronavirus (CoV)-229E/OC43/HKU1/NL63 and rhinovirus (RV). Chi-square test and Fisher exact test were used to analyze the epidemiological characteristics of ARI cases. Results:Of the 726 ARI cases enrolled, 316 (43.53%) were positive for at least one viral pathogen, of which, 40 cases had dual infection and 9 had triple infection. The viral infection rates in different age groups were significantly different. The main viral pathogens in ARI in Fuzhou in 2019 were IFVs (12.40%), followed by Adv (10.61%), RV (8.82%), and RSV (5.51%). The AdV infection was more common in male ARI cases, and IFV-B, PIV, RSV, RV, and AdV were identified more commonly in children. In addition, the infection with IFVs, RSV, and RV had obvious seasonality.Conclusions:The main pathogens of ARI cases in Fuzhou in 2019 include IFVs, AdV, RV, RSV, etc. The infection of respective virus in ARI cases represent different age-distribution and seasonality.

Objective: To study the etiological characteristics of an imported Chikungunya fever (CHIK) epidemic in Fujian province in 2018. Methods: Serum samples collected at different days after the onset of the two CHIK cases were detected by real-time RT-PCR and ELISA. Structural protein E1 gene was amplified by RT-PCR and sequenced for nucleotide characteristics analysis and phylogenetic tree analysis. Results: RNA of Chikungunya virus (CHIKV) was detected in the 4 serum samples collected on the first 5 days of the disease, and the earliest IgM antibodies were detected in specimens on the 5th day of the disease, however, IgG antibodies were only detected in specimen on 10th day. Compared with the S27-African prototype strain, 12 mutant points were found in the amino acids of E1 genes in this study. The E1 genes of the two CHIK cases were exactly the same, and they were closest to the evolutionary relationship with the strain isolated in the Philippines in 2014. Their genotype was Asian genotype. Conclusions This epidemic was confirmed to have been imported from the Philippines after the infection with the Asian genotype CHIKV, which suggests that Fujian province should strengthen the monitoring of persons entering from the CHIK epidemic area, so as to prevent imported cases from causing local outbreaks.

Objective: To provide effective reference of laboratory detection and prevention-control in avian influenza epidemic via analyzing the detection result of the first case infected avian influenza H5N6 virus in Fujian province. Methods: The viral RNA was extracted from the patient’s throat swab and specimens of surrounding environment, and detected by real-time RT-PCR. The gene sequences of HA and NA gene segments were obtained by RT-PCR and sequencing, the evolution characteristics of the virus were elementarily analyzed by bioinformatics. Results: The avian influenza H5N6 virus was confirmed from the patient’s throat swab, termed influenza A/Fujian-Sanyuan/21099/2017(H5N6)virus. The throat swabs of case from 5 different time points were collected and the H5N6 nucleic acid were detected from the first three times collection. Among 43 specimens of surrounding environment, there were 16 H5 virus samples. The HA and NA gene segments of A/Fujian-Sanyuan/21099/2017 were closely related to A/Cygnus atratus/Hubei/2Z2-O/2016(H5N8) and A/chicken/Hubei/ZYSJF16/2016(H5N6), with a similarity of 99.6% and 99.0% respectively. The cleavage site of HA gene contained multiple basic amino acids. Conclusions The suspected case was the first case infected with avian influenza H5N6 virus in Fujian province, and the HA and NA genes of virus were highly similar to those of H5N8 and H5N6 virus respectively.

Objective To investigate the genetic characteristics and mutations in hemagglutinin ( HA) genes of influenza A subtype H3N2 viruses isolated in Fujian province during 2014—2016. Methods HA gene fragments of 44 randomly selected influenza A (H3N2) viruses were amplified by RT-PCR and then sequenced by Sanger sequencing. Obtained sequences were analyzed by bioinformatics software and on-line websites. Results Pair-wise similarity among HA genes of the 44 strains was between 97. 3%-100. 0% at nucleotide level. The average variations between epidemic strains and corresponding vaccine strains in the year of 2014, 2015 and 2016 were 0. 012, 0. 008 and 0. 009, respectively. The genotype of epidemic strains in 2014 was 3C. 3a rather than 3C. 1 of the vaccine strain. Notably, variations at some antigenic sites, re-ceptor binding sites ( RBSs) and N-Glycosylation sites were identified despite the fact that the genotypes were identical between epidemic and vaccine strains in 2015 and 2016. Conclusion Variations at the HA genes of influenza A (H3N2) viruses in Fujian province occurred during the year of 2014—2016, reflecting the ability of circulating strains to escape the vaccine-induced immunity. Sustainable influenza surveillance and prompt identification of viral variants would benefit influenza prevention and control.

To study the biological characteristics and mutations of influenza A(H1N1)pdm09 virus isolated from one case of pneumonia of unknown etiology (PUE),which would provide references for clinical treatment and disease control,the throat swab specimen from the PUE case was isolated in the Madin-Darby Canine Kidney (MDCK) cells,and then the antigenicity,pathogenicity and drug resistance of influenza A (H1N1) pdm09 virus were analyzed after sequencing.As a result,one influenza virus strain was isolated from the specimen and named as A/FujianGulou/SWL64/2016(H1N1).The similarities of nucleotide sequences and amino acids sequences compared with the vaccine strain A/California/07/2009 (H1N1) were 96.9％-98.9％ and 96.7％-99.5％,respectively.Eighteen amino acids had mutated in the HA and 4 mutations,K163Q,S185T,S203T and D222N,were involved in 3 different epitopes,which indicated that the antigenic drift had occurred in the influenza virus.The D222N mutation associated with receptor binding site made the virus infect lower respiratory tract more easily.The virus was still amantadine-resistance and oseltamivir-sensitive.In conclusion,the influenza A (H1N1) pdm09 virus in this study have occurred antigenic drift and has the molecular characterization of causing severe pneumonia,so further surveillance should be performed to prevent and control the influenza epidemic.

Objective: To understand the epidemiological and virological features of influenza B viruses and the difference between the vaccine strains and epidemic strains, the antigenic and genetic characteristics on hemagglutinin (HA) gene of influenza B viruses circulating in Fujian during 2010-2015. Methods: The representative strains were selected randomly according to the lineage of influenza B viruses isolated from network laboratory in Fujian, 2010-2015. Viral RNA was extracted and gene fragments were amplified by reverse transcription polymerase chain reaction (RT-PCR ) and the PCR products were sequenced. The complete HA gene sequence was obtained and analyzed via bioinformatics. Results: Compared to the vaccine strains recommended by WHO, there were significant changes in genetic and antigenic characteristics on HA gene of B Yamagata lineage viruses from 2010 to 2015, especially in 2010, 2014 and 2015. There were major five amino acid residues substitutions (116, 150, 165, 196 and 202) involved in antigenic determinants, and the variable sites gradually increased as time on over. However, the variability of B Victoria lineage viruses on HA gene was less and there was no obvious trend over time. The results showed that the B Yamagata vaccine strains of 2010 and 2015 recommended by WHO had poor protective effect on influenza virus infection, while the B Victoria vaccine strain still play a satisfactory protective effect on humans in Fujian. Conclusions With time on, influenza B Yamagata lineage viruses had gradually mutated, causing a poorly match with vaccine strains in part of year, and emerging antigenic drift phenomenon. Strengthening further surveillance of mutations of B influenza virus remains essential to allow for early warning of influenza epidemic.

Objective: In this study, we tested for the presence of four human coronaviruses (HCoVs) in children with respiratory tract disease in Fuzhou, Fujian, China. Methods: Nasopharyngeal aspirates were collected from children with respiratory tract disease from Nov, 2007 to Jan, 2015. A total of 266 clinical samples were tested for HCoVs using reverse-transcription polymerase chain reaction (RT-PCR). The positive products were sequenced and compared with those in GenBank by BLAST. The positive samples were then tested for HCoV-HKU1 and HCoV-NL63 using RT-PCR method . We compared the 440 bp pol gene sequence of the 8 HCoV isolates in Fuzhou, China to other HCoV isolates documented in the GenBank database by using MEGA software version 6.06 and the neighbor-joining method . Results: HCoVs were detected in 8 patients (3.0%) out of the 266 children. Two of 266 (0.38%) were positive for HCoV-HKU1; 1 of 266(0.38%)were positive for HCoV-NL63; 1 of 266 (0.38%) were positive for HCoV-229E; 4 of 266 (1.5%)were positive for HCoV-OC43. All of children who were positive for HCoV had respiratory illness. Two HCoV-HKU1 were found to co-infect with human parainfluenza virus type 3 (HPIV-3). The 8 HCoV strains in our study fell into four clusters. Two strains of HCoV-HKU1 were genotype A. Conclusions HCoV infections were probably associated with upper and lower respiratory illness in children. Additional studies are needed to investigate the potential roles of these HCoVs in diseases.

Objective: To make laboratorial diagnosis of imported yellow fever (YF) cases in Fujian province with molecular method . Methods: Serum and urine samples were collected from suspected cases at various time-points post illness onset. Real-time RT-PCR and nested RT-PCR were performed respectively for viral specific nucleotide detection and fragment amplification. Sequencing and restrictive fragment length polymorphism (RFLP) method were used to identify the wild virus infection. Results: A total of five cases with wild yellow fever virus (YFV) infection were confirmed in this study. It revealed that the viral agent belonged to Angola-71 like YFV, and the duration of viral agent in urine was longer than that in serum. Conclusions Simultaneous detection of serum and urine samples would increase detection sensitivity, and further RFLP method contributed to rapid identification of wild YFV infection and exclusion of positive result due to recent vaccination.