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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.
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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.
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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.
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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.
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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.
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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.
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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.
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<p><b>OBJECTIVE</b>To study the molecular epidemiology of hand-foot-mounth disease (HFMD) associated Coxsackievirus A10 (Cox A10) identified in Fujian province.</p><p><b>METHODS</b>A total of 1 525 specimens from non-EV71 non-Cox A16 HFMD patients were collected during 2011-2014. Isolated virus strains were identified and sub-typed. Full-length coding regions for the VP1 gene of the predominant serotype Cox A10 isolates were amplified and sequenced.</p><p><b>RESULTS</b>Among the 407 non-EV71 non-Cox A16 HFMD cases confirmed by virus isolation and molecular subtyping, 103 (25.3%) were caused by Cox A10, accounting for 11.0%, 6.0%, 18.4% and 9.2% among the HFMD-associated entero-viruses identified in 2011, 2012, 2013 and 2014, respectively, in Fujian province. Compared to the general features observed in the HFMD epidemics, no differences on the Cox A10-specificity rates were observed among factors as geographical origins, gender or age groups, but all with high rates of severity. Data from the nucleotide sequence analyses on VP1 genes showed low homology levels of 76.0%-77.1% among Cox A10 strains from Fujian province, in contrast to the prototype Cox A10 strain, but with high levels of homology in the amino acid sequences (91.9%-93.6%). RESULTS from the Phylogenetic analysis also indicated that Cox A10 isolates from Fujian province were distinct from the prototype strain or other isolates from other countries but was homologous to domestic strains, but the Fujian isolates clustered into multiple branches.</p><p><b>CONCLUSIONS</b>Cox A10 remained one of the predominant serotypes of HFMD in Fujian province. Cox A10 isolates identified in Fujian province were co-circulating and co-evolving with other domestic strains.</p>
Subject(s)
Child , Child, Preschool , Female , Humans , Infant , Male , Benzeneacetamides , China , Epidemiology , Enterovirus A, Human , Classification , Genetics , Epidemics , Hand, Foot and Mouth Disease , Epidemiology , Genetics , Virology , Molecular Epidemiology , Molecular Sequence Data , Open Reading Frames , Phylogeny , Piperidones , SerogroupABSTRACT
In order to investigate EV71 antibody levels among general population from Fujian Province after the 2008‐2009 HFMD epidemics ,390 sera‐specimens were collected from 390 participants in 2010 .EV71‐specific antibody was detected by neutralization test ,indicating 186 (47 .69% ) sera of 390 were EV71‐seropositive .Although the difference by gender was not statistically significant on positive rates and antibody titers ,significant differences were observed in positive rates and antibody titers among age groups .The positive rate was increasing with age ,while the 0 age‐group yielded the lowest positive rate of 16 .67% .Subsequently ,significant difference was detected among positive rates and antibody titers between age groups of 0 to 4 years‐old and 5‐years‐old ,with the positive rate of 25 .33% and 61 .67% ,respectively .Therefore ,the EV71 antibody levels among general population from Fujian Province after the 2008‐2009 HFMD epidemics was still in the low level ,especially the age groups of 0 to 4 years‐old .The epidemic of HFMD mainly caused by EV71 will still occur in the future ,and children under 5 years old are major susceptible population ,continuously intensive surveillance ,prevention and control are required .