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Objective@#To elucidate the epidemiological and etiological features of a local outbreak of dengue fever (DF) in Taijiang district in Fuzhou, Fujian province in 2017, and speculate possible viral source based on phylogenetic analysis.@*Methods@#The clinical and demographic data of cases were collected through field investigation and the outbreak was characterized epidemiologically by descriptive method. The patient′s serum were collected and the adult mosquitoes were captured by anti-mosquito double-net method for the laboratorial test and viral isolation. The viral isolates were typed by real-time fluorescent RT-PCR and their full length of viral envelope (E) genes were amplified by RT-PCR and sequenced. The E gene sequences obtained in this study, together with the reference sequences, were used for the phylogenetic analysis.@*Results@#A total of 13 cases of autochthonous DF were confirmed in the outbreak. All cases presented obvious clinical manifestations and clustered spatially and temporally. The Breteau Index (BI) of mosquito larva density was the highest in epidemic foci of Xingang street and was relatively low in surrounding areas. Four DENV-1 strains, three from patients and one from the captured adult Aedes albopictus, were isolated and identified by real-time RT-PCR. Full length E gene sequences of the four isolates were completely identical and phylogenetic analysis showed that the isolates were genetically closest to the strain (GenBank No. KT825033) from Vietnam in 2014, rather than the DENV-1 strains found in Fujian previously.@*Conclusions@#The DF outbreak occurred in Fuzhou in 2017 was caused by DENV-1 which was imported possibly from somewhere outside of Fujian province and subsequently led to local DF transmission in human via the mosquito Aedes albopictus.
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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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Severe infectious diseases,i.e.antibody-dependent enhancement (ADE) resulted from successive infection with different serotypes of dengue virus.After its introduction into Brazil in 2015,Zika virus has spread rapidly to more than 60 countries and regions by the end of November 2016.Some south-east Asian countries including China have also reported cases of ZIKV infection.In recent studies,it was observed that sera cross-reactivity antibodies or such monoclonal antibodies have been elicited by two domains,ED1 and ED2,of envelope (E) protein on Zika or/and Degue virus,and ADE was easily induced by such antibodies.Dengue fever epidemic often occurred in Chinese coastal provinces each year.Then,it will be followed by Zika virus disease.Therefore,we must pay attention to and propose replying measurement for it.
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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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For investigating the epidemiology and genetic characteristics of enterovirus 71 (EV71) in Fujian from 2010 to 2015,we analyzed the surveillance data of EV71 and sequenced VP1 genes of 72 EV71 strains randomly picked from the past 6 years.The overall infection rate was gradually down and one incidence peak (from May to July) was observed each year.Major infectious population were focused on Xiamen,Fuzhou,Nanping and Quanzhou,the ages ranged from one to three years old.Scattered children were the most infected ones.The proportion of EV71 in the severe case was higher than in the HMFD(χ2 =732.064 5,P＜0.000 1).EV71 circulated from 2010 to 2015 in Fujian Province was belonged to subgenotype C4a in consistent with vaccine strain (H07).Compared with the VP1 of vaccine strains,the divergence of complete VP1 nucleotide sequence was gradually expanding as time distance increased,but the sequence of amino acid was not found obvious difference.Variations in 4 key immune epitopes of amino acid had not appeared a regular pattern in year and not consistent with the trend of proportion of EV71 in HMFD.As a result,we considered the epidemiology characteristics of EV71 in Fujian was obvious,72 strains still belonged to C4a subgenotype and had no outstanding antigenic drift or mutation.Extensive epidemiology surveillance and genetic characteristic are needed for the application of EV71 vaccine.
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<p><b>OBJECTIVE</b>A Dengue outbreak was reported in Dongfen town Jianou county, Fujian province on September 19, 2014. The goal of this project was to explore the role of syndromic surveillance program in the practice of early detection on disease outbreak through the case mentioned above.</p><p><b>METHODS</b>The authors retrospectively collected data related to Outpatient log and Pharmacy drug use in Dongfen township hospital through the electronic information system of the hospital from August to November, 2014. All the abnormal events were recorded, according to related data on fever and drug use. Description of fever, syndromic characteristics, correlation and Linear regression analyses were conducted, using the surveillance data on fever syndrome and drug use from the pharmacy.</p><p><b>RESULTS</b>A total of 1 102 cases with fever and 2 437 fever-related clinic visits were reported which showing an increased number of 19.6, 10.2 times respectively, when compared to the same period of the previous year in which men accounted for 45.3% (499/1 102) and female accounted for 54.7% (603/1 102). Age groups presented an atypical type " M" type. 5 and 10 year olds groups formed the largest proportion, accounted for 11.5% (127/1 102) of the total number os the patients. The correlation coefficient ranged from 0.85 to 0.97 (P<0.05). Data from the syndromic surveillance program showed an " outbreak" was occured in August 23, 2014.</p><p><b>CONCLUSIONS</b>Compared to routine surveillance program, the syndromic surveillance program could detect the appearence of an outbreak, a month or even more earlier. The role of syndromic surveillance program needs to be further explored.</p>
Subject(s)
Female , Humans , Male , Data Collection , Dengue , Diagnosis , Epidemiology , Disease Outbreaks , Drug Prescriptions , Drug Utilization , Early Diagnosis , Fever , Health Information Systems , Pharmacy Service, Hospital , Population Surveillance , Methods , Retrospective StudiesABSTRACT
<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
<p><b>OBJECTIVE</b>To identify clinical characteristics of hospitalized laboratory-confirmed influenza cases of children under 15 years old, and their risk factors of influenza infection.</p><p><b>METHODS</b>Analyzing the reports of hospitalized laboratory-confirmed influenza cases of children under 15 years old who were detected by the sentinel surveillance systems in 10 provinces from December 2009 to June 2014. Such data as their demographic, medical history, clinical symptoms and signs, treatment and outcome were collected using questionnaires, with their clinical characteristics and their risk factors of influenza infection described.</p><p><b>RESULTS</b>Of the 2 937 severe acute respiratory infection inpatients, 190 (6.5%) were laboratory-confirmed influenza cases. 123 (64.7%) of such confirmed cases were male, and 139 (73.2%) were children under 5 years old, with age median of 3.0 years (IQR: 1.0-5.0 years). 20 (10.5%) of them had at least one chronic medical condition, mostly chronic cardiovascular disease (3.2%), immunosuppressive disease (3.2%), and cancer/tumor (2.6%). Most common clinical symptoms of the cases were fever (92.6%) and cough (88.8%), of which abnormal pulmonary auscultation (51.1%) and abnormal chest X-ray performance (36.1%) were the most common clinical signs. 29 cases (15.8%) had complications, of which pneumonia (15.3%) was most common. 16 cases (8.6%) used antiviral drugs, and 4 cases (2.2%) were admitted into ICU. Risk factor analysis suggested that age < 6 months (OR = 0.406, 95% CI: 0.203-0.815) was a protective factor against influenza infection; and age 5-9 years old (OR = 2.535, 95% CI: 1.059-6.066) was a risk factor for influenza infection.</p><p><b>CONCLUSION</b>Hospitalized laboratory-confirmed influenza cases were found mostly in children under 5 years old. Risk exposure for influenza infection varied among age groups.</p>
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Adolescent , Child , Child, Preschool , Female , Humans , Male , Acute Disease , Antiviral Agents , China , Epidemiology , Cough , Fever , Hospitalization , Influenza A Virus, H1N1 Subtype , Influenza, Human , Epidemiology , Pathology , Inpatients , Laboratories , Protective Factors , Risk Assessment , Risk Factors , Sentinel Surveillance , Surveys and QuestionnairesABSTRACT
<p><b>OBJECTIVE</b>To investigate clinical and epidemiological characteristics of hospitalized severe acute respiratory illnesses (SARI) patients under 15 years old registered by sentinel hospitals at 10 cities and risk factors analysis of severe illness.</p><p><b>METHODS</b>The objects of this study were 2 937 SARI patients under 15 years old registered by sentinel surveillance in internal wards, pediatrics wards and intensive care units (ICU) of 10 sentinel hospitals in 10 cities during the period from December 2009 to June 2014. We also collected case report form (CRF) of them and their throat swabs for influenza testing. The inclusion criteria was hospitalized patients who were admitted by surveillance departments, registered by SARI surveillance system, under 15 years old, meeting SARI case definition and with complete CRF. Rank-sum test was used to compare the difference of age, the duration including from onset to admission, hospital stay and from onset to discharging/death between mild illness and severe illness. Chi-square test was used to compare the difference of demographic characteristics, influenza psoitive rate, vaccination rate of influenza, chronic medical conditions and clinical characteristics between mild illness and severe illness. Logistic regression was used to analysis risk factors associated with severe illness by two stratifications from SARI surveillance protocol (< 2 years old and ≥ 2 years old).</p><p><b>RESULTS</b>Among 2 937 SARI patients under 15 years old, 97.7% (2 872/2 937) was mild illnesses, and 2.3% (65/2 937) was severe illnesses. 78.8% (2 315/2 937) was under 5 years old. The median ages of severe illness and mild illness were 0.4 and 2.0 years old (U = -6.23, P < 0.001). The proportions of severe illness and mild illness with at least one chronic medical condition were 32.3% (21/65) and 8.4% (240/2 872) (χ² = 45.03, P < 0.001). The positive rate of influenza virus was 6.5% (190/2 937), which was 6.5% (186/2 858) for mild illness and 6.2% (4/65) for severe illness (χ² = 0.08, P = 0.961). The proportion of seasonal influenza vaccination was 1.5% (42/2 853), which was 1.5% (42/2 788) for mild illness and higher than that for severe illness (0) (χ² = 6.09, P = 0.048). For under 2 years old patients, age < 11 months and with at least one chronic medical condition were risk factors for severe SARI illness, and the risk for SARI patients who was 12-23 months and without medical condition was 14.71 (5.35-40.44) and 5.61 (2.96-10.63). For ≥ 2 years old patients, age, with at least one chronic medical condition and seasonal influenza vaccination history have no association with severe illness, OR (95% CI) was 0.92 (0.80-1.05), 0.67 (0.09-5.05) and 0.85 (0.31-2.35), respectively.</p><p><b>CONCLUSION</b>Most of SARI patients registered by 10 urban sentinel hospitals were patients under 5 years old. Age < 11 months and with at least chronic medical conditions were possible risk factors of severe illness of SARI patients.</p>
Subject(s)
Adolescent , Child , Child, Preschool , Humans , Infant , China , Chronic Disease , Cities , Hospitalization , Hospitals , Influenza, Human , Orthomyxoviridae , Respiratory Tract Diseases , Risk Factors , Sentinel Surveillance , VaccinationABSTRACT
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 .
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Since several dengue viruses (DENV) have been isolated in Fujian Province during the past decade, sequencing and evolution analyses of viral envelope genes are helpful in determining their possible transmission origins. In this study, viral RNA was extracted from 12 DENV strains from Fujian between 20042010. Viral envelope genes were amplified, cloned into TA vectors and sequenced, and the sequence data were subsequently analyzed by bioinformatics software. Full-length E genes of DENV-1 or DENV-2 of 1 485 bp, and DENV- 3 of 1 479 bp were obtained. It was indicated, from BLAST analysis and phylogenetic trees, that DENV strains in Fujian Province during 20042010 shared the highest similarity with Southeast Asian strains, suggesting that DENV circulating in Fujian Province between 20042010 were probably imported from Southeast Asia. Hence, extensive monitoring on passengers from this region at the entry-ports should be strengthened.
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Dengue is the most common vector borne viral disease of humans globally.Detection of viral RNA from suspected patient specimens is rapid,specific and confirmative in laboratory diagnosis of dengue infections during the acute phase.In this study,a multiplex nested reverse transcription PCR (RT-PCR) system was established for clinical specimens.While other nucleic acid amplification tests showed relatively low sensitivity,the multiplex nested RT PCR assay detected 4 cases among blood clots from 8 serologically confirmed dengue patients.These results suggested that blood clots of dengue patients could be used in laboratory diagnosis,and that the multiplex nested RT PCR assay,which simplified the detection procedure,could facilitate viral RNA detection of specimens in clinical laboratories.
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<p><b>OBJECTIVE</b>Using heteroduplex mobility assay (HMA) to subtype human immunodeficiency virus type 1 (HIV-1) for the purpose of understanding HIV-1 subtype epidemic in Fujian province.</p><p><b>METHODS</b>DNA fragments of HIV-1 env gene were amplified from peripheral blood mononuclear cell (PBMC) cocultures of HIV-1 infected individuals by nested polymerase chain reaction (PCR). Heteroduplexs were formed through hybridizing PCR products from the samples and reference plasmid. According to the mobility of heteroduplexs in polyacrylamide gel electrophoresis, HIV-1 subtype from that sample was characterized and further confirmed by nucleotide sequencing analysis.</p><p><b>RESULTS</b>Thirteen of 15 (86.67%) samples were successfully subtyped by HMA, except 2 failures. Subtype E and B took up 80% (12/15) and 6.67% (1/15) respectively. Results indicated a high concordance between HMA and nucleotide sequencing analysis and concordance rate was 86.67% (13/15).</p><p><b>CONCLUSIONS</b>Subtype E appeared to be the major epidemic strain of HIV-1 in Fujian. HMA showed the characteristics of fastness, easiness, economic and with high specificity, and can be used in the surviellance for the epidemic strain of HIV-1.</p>