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.

Objective To obtain the information of the 2009 influenza outbreak and the variations of influenza virus strains in quanzhou, and explore the relationship between the genetic variation of influenza virus and influenza epidemic. Methods During the influenza outbreak in quanzhou,one hundred and ninetyeight throat swabs specimens from the patients with influenza were collected. Viruses were isolated with MDCK cells and identified with serological test, followed by real-time RT-PCR. RNA of four influenza virus strains were extracted, then HA1 gene was amplified by RT-PCR. The purified PCR products were sequenced. The data were analyzed with the software DNAstar megalign. Results Total 98 pieces of H3N2 subtype influenza virus nucleic acid were detected in 198 throat swabs specimens,among which 62 influenza virus strains were identified as subtype influenza A( H3N2 ). The sequencing results of HA1 gene in these positive strains showed that their genetic characterization were more closed to strains A/Ningbo/333/2008 with a nucleotide homology of 98.7%, which was 96.8% as compared with A/Xiamen/70/2004. The amino acids sequences deduced from the nucleotide sequences in HA1 region of the isolated strain had 7 mutant sites compared with A/Brisbane/10/2007 vaccine strain. One variant amino acids were found located in the antigenic determinant sites A( 144 ), two were in the sites B( 158,189 ). Phylogenetic analysis also confirmed the difference in HAl domain. Conclusion The influenza virus strains causing the flu outbreak among some communities of quanzhou in 2009 are subtype influenza A ( H3N2 ), whose genetic characterization and antigenicity were different from the vaccine strain.

Objective To investigate the influenza H1N1 virus surveillance of 2009 in Quanzhou,and analyze the HA and NA gene of influenza H1N1 virus, explore its genetic variation and molecular characteristics. Methods During the influenza H1N1 virus surveillance in Quanzhou,specimens of throat swabs from the patients with influenza were collected, and detected by real-time RT-PCR. Viruses were isolated with MDCK cells and identified with serological test. Two influenza virus isolates were extracted, and their HA and NA genes were amplified by RT-PCR. The purified PCR products were sequenced. The data obtained were analyzed with the software DNAMAN. Results Of 1020, influenza H1N1 virus RNA was detected in 200 specimens, seasonal influenza virus RNA was detected in 70 specimens. A total of 29 influenza A H1N1 virus strains were isolated. The nucleotide homology in the HA gene was highly homologous with that of pandemic influenza virus in North America. The amino acids sequences deduced from the nucleotide sequences in HA region of the isolated strain had 22 variations compared with A/Brisbane/59/2007 vaccine strain recommend by WHO,the characteristics of α2,6 sialic acid receptor binding remained. The analysis of amino acids sequences of NA indicated that this virus possessed Oseltamivir sensitivity. Conclusion The causative influenza H1N1 strains in Quanzhou is highly homologous with that of pandemic influenza in North America, and it is antigenically and genetically different from the vaccine strain.

Objective: To understand the etiology, genotype and molecular characteristics of acute viral gastroenteritis in Quanzhou from 2014 to 2017. Methods: Specimens from 15 outbreaks of acute viral gastroenteritis in Quanzhou area from 2014 to 2017 were collected and real-time fluorescence quantitative PCR was used to detect norovirus GI and GII, sapovirus, astrovirus and rotavirus, and the result were statistically analyzed. Furthermore, specimens positive for norovirus was further subjected to the amplification and sequencing of polymerase and VP1 genes of norovirus, and sequences were analyzed using DNAstar and MEGA7.0 software. Results: In this study, 96 specimens from 15 outbreaks of acute viral gastroenteritis were collected, and norovirus was detected in 30 specimens with a positive rate of 31.25%, among which 23 specimens were genotype GII and 7 specimens genotype GI. Meanwhile, 10 specimens were randomly selected for nucleic acid sequence analysis. The result showed that 9 of them were GII.P16/GII.2 and 1 was GI.6. The phylogenetic analysis showed that the new recombinant norovirus subtype GII.P16/GII.2 was highly homologous to the same subtype detected in outbreaks home and abroad recently. Conclusions The main pathogens caused the outbreak of acute viral gastroenteritis in Quanzhou from 2014 to 2017 were norovirus belonging to subtype GII.P16/GII.2 and subtype GI.6, and subtype GII.P16/GII.2 was the predominant strain which was found for the first time in Quanzhou.

Objective: To analyze the distribution and the molecular biological characteristics of variant subtypes (H5, H7 and H9) of avian influenza virus (AIV) in the live poultry related external environment of Quanzhou form 2014 to 2017, and provide regional references for the prevention, control and early-warning of human infections. Methods: Samples from monitoring sites of live poultry were collected in Quanzhou from 2014 to 2017. Influenza A and variant subtypes of AIV (H5, H7 and H9) were detected by real time RT-PCR, and the detection results were further analyzed statistically. Furthermore, the HA and NA genes of four representative H7N9 strains were sequenced, and the results were further analyzed with DNAstar and MEGA7.0. Results: Among the samples from external environment, the positive rate of nucleic acid of influenza A was 29.04% (377/1 289), of which the positive rates of H5, H7 and H9 subtypes were 3.80%, 13.34% and 12.02%, respectively. The positive rate of H7N9 was higher than those of the other subtypes in all monitored years, of which the highest rate was found in 2017 (21.88%). As to the different types of samples, chopping board possessed the highest positive rate of influenza A (65.4%), followed by waste water (59.3%) and drinking water for the poultry (29.6%). Among the different monitoring sites, the positive rate of poultry farm is 6.94%, far lower than that in the open air (61.7%) and the live poultry trading market (52.8%). Sequencing of the HA and NA genes of four strains of H7N9 showed that the strains from external environment and the strains from H7N9 patients belonged to Pearl River Delta and Yangtze River Delta lineage, respectively. The cleavage sites of HA proteins of these four strains were all PKGR/G without highly pathogenic mutation. Meanwhile, they were low pathogenic H7N9 without oseltamivir resistant mutation (R292 K in NA), while they all possessed the E627 K mutation in the PB2 genes associated with virulence. Conclusions H7N9 AIV existed in the live poultry related external environment of Quanzhou, especially the farmers’ and the live poultry trading market, so that more persistent surveillance could be needed in the future.