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.

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.

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.

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.

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.

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 .

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.

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: To explore the application values of prenatal ultrasound, vascular cast in the diagnosis of fetal aortic arch and its branches anomalies and to analyze the genetic characteristics by gene detection. Methods: Twenty-two cases of the vascular cast specimens of the fetal aortic arch and its branches anomalies were analyzed and studied by comparing with their prenatal ultrasonography. Then the characteristics of each type of fetal aortic arch and its branches anomalies, the missed diagnosis and misdiagnosis were summarized and the results of their gene detection were also analyzed. Results: The 22 cases of fetal aortic arch and its branches anomalies were as follows: 2 cases of double aortic arch showed the ascending aorta was divided into two branches after converging as the descending aorta. Three cases were left aortic arch with aberrant right subclavian artery. Twelve cases were right aortic arch: 8 cases were right aortic arch with mirror-image branching, 3 cases were right aortic arch with aberrant left subclavian artery, 1 case was right aortic arch with isolated left subclavian artery. Of the 8 right aortic arch with mirror-image branching, 3 cases of left arterial duct showed the vertical walking between the fusion site of the left innominate artery and the pulmonary artery. Right aortic arch with aberrant left subclavian artery with arterial duct showed "U" shaped vascular ring. Five cases were other types, including 2 cases of the coarctation of aortic arch, 1 case of interrupted aortic arch, 1 case of pulmonary artery sling, and 1 case of abnormal origin of right pulmonary artery. The ultrasonic missed diagnosis were the 6 deformities: 3 cases of arterial duct and 3 cases of aberrant subclavian artery. The ultrasonic misdiagnosis were the 5 deformities: 2 cases of arterial duct location, 1 case of aberrant subclavian artery, 1 case of isolated left subclavian artery, and 1 case of the coarctation of aortic arch. Genetic test results: In the 18 cases of the genetic detection, 2 cases were positive, 1 case was 22q11.2 microdeletion syndrome and 1 case was carrying KMT2D gene variant. Conclusions There are various kinds of fetal aortic arch and its branches anomalies, which are often associated with intracardiac malformations and venous branches variation. And prenatal ultrasound is of great value in diagnosing them.Vascular cast can visually display their characteristic changes, which is helpful to improve the differential diagnosis of the different aortic arch and its branches anomalies. The detailed genetic detection can improve the further understanding of its etiology.

OBJECTIVETo study the molecular epidemiology of hand-foot-mounth disease (HFMD) associated Coxsackievirus A10 (Cox A10) identified in Fujian province.

METHODSA 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.

RESULTSAmong 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.

CONCLUSIONSCox 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.

Benzeneacetamides ; Child ; Child, Preschool ; China ; epidemiology ; Enterovirus A, Human ; classification ; genetics ; isolation & purification ; Epidemics ; Female ; Hand, Foot and Mouth Disease ; epidemiology ; genetics ; virology ; Humans ; Infant ; Male ; Molecular Epidemiology ; Molecular Sequence Data ; Open Reading Frames ; Phylogeny ; Piperidones ; Serogroup