No abstract available.
Humans ; Influenza A Virus, H1N1 Subtype/*isolation & purification ; Influenza, Human/*diagnosis

OBJECTIVETo investigate the prevalence and subtypes of influenza viruses in Liaoning regions from November 1999 to March 2005.

METHODSInfluenza virus was isolated by embryonated eggs together with cell culture and subtypes, identified by HI test.

RESULTSDuring the study in 1999 - 2005, a total number of 2713 swab specimens were collected in different cities in Liaoning regions in which 188 strains were identified for influenza viruses with an average rate as 7.0%. A total number of 1466 swab specimens were collected by both Centers for Disease Control and Prevention in Dalian city and Liaoning province, and 167 strains were identified positive with an average rate of 11.4%. Influenza A3, A1 and B/Yamagata all appeared before March 2002 which were predominant strains. However, since then Influenza A1 has never appeared again in Liaoning regions and B showed some changes, from Yamagata to Victoria, the characteristics on the prevalence of influenza appeared only in the period of November to February.

CONCLUSIONIt was meaningful to analyze the surveillance data of influenza in different years in Liaoning regions in order to better understand the characteristics of influenza and the shifting of subtype.

China ; epidemiology ; Humans ; Influenza A virus ; classification ; isolation & purification ; Influenza B virus ; classification ; isolation & purification ; Influenza, Human ; epidemiology ; Population Surveillance ; Seasons

OBJECTIVETo establish and evaluate a single-tube multiplex RT-real time PCR assay for detecting novel influenza A H1N1, influenza A and influenza B viruses (called "IV" for short) simultaneously.

METHODSA total of 213 clinical specimens of influenza-like patient's throat swab were collected during October 2010 and April 2011. 152 bp fragment in HA gene of novel influenza A H1N1 virus, 128 bp fragment in M gene of influenza A virus and 107 bp fragment in NP gene of influenza B virus were chosen as the target genes for multiplex RT-real time PCR, a specific primers and probes labeled with different fluoresceins were designed. The standard plasmid was constructed using in vitro transcription assay, and the standard curve was established. The reproducibility, specificity and sensitivity of the assay were evaluated. Furthermore, RNA extracted from 213 clinical specimens of throat swab was detected and verified by sequencing.

RESULTSThe corresponding standard curves of novel influenza A H1N1 virus, influenza A virus and influenza B virus were Y = - 3.46 lgX + 46.985, Y = - 3.49 lgX + 37.709, Y = - 3.51 lgX + 38.889, respectively; Y was cycle threshold (Ct), and lgX was logarithm value of virus replication number. The standard curve coefficient was 0.998. The detection limit of this assay was 10(2) copies/microl in one reaction. The specificity was strong. 39 (18.3%), 63 (29.6%) and 23 (10.8%) of 213 clinical specimens detected were positive for novel influenza A H1N1 virus RNA,influenza A virus RNA and influenza B virus RNA respectively. The positive samples were verified by sequencing.

CONCLUSIONThe single-tube multiplex RT-real time PCR assay developed in this study for detecting and identifying novel influenza A H1N1, influenza A and influenza B viruses simultaneously was rapid, specific and sensitive.

Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; isolation & purification ; Influenza A virus ; genetics ; isolation & purification ; Influenza B virus ; genetics ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; methods

OBJECTIVETo analyse seasonal influenza epidemic situation in 2006, and to analyse the genetic and antigenic characteristics of viral hemagglutinin (HA) gene.

METHODSThe single-way hemagglutination inhibition (HI) tests were used to test the antigenic characteristics of these viruses from influenza surveillance network, and the HA1 genes were sequenced based on the antigenic test results according to different isolation times and sites.

RESULTSThe influenza virus types A and B co-circulated in 2006. influenza A H1N1 subtype and Victoria-like B influenza circulated preponderantly during this epidemic season. The HA1 gene sequence of H1N1 viruses showed that 192, 193, 196, 198 positions (located at antigenic site B) have an amino acid substitute, compared with the last circulating strain A/Hubeihongshan/53/2005(H1N1). Two amino acid changes at 142 and 144 positions compared with A/Yunnan/1145/2005 (H3N2). There was no change in influenza B viruses either Victoria-like B or Yamagata-like B virus, i.e . antigenic characteristics is analogous to B/shenzhen/155/2005 and B/tianjin/144/2005, respectively.

CONCLUSIONThe H1N1 and H3N2 influenza viruses had changing antigenic and genetic characteristics in 2006. Influenza virus types B did not change in 2006.

Amino Acids ; analysis ; China ; Hemagglutination Inhibition Tests ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; immunology ; Influenza A Virus, H1N1 Subtype ; immunology ; isolation & purification ; Influenza A Virus, H3N2 Subtype ; immunology ; isolation & purification ; Influenza B virus ; immunology ; isolation & purification ; Time Factors

No abstract available.
Hepatitis A/*epidemiology ; Humans ; Influenza A Virus, H1N1 Subtype/*isolation & purification ; Influenza, Human/*epidemiology

Animals ; China ; Influenza A virus ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Nucleic Acids ; genetics ; Poultry ; virology

OBJECTIVETo analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market (LPM) in 2009 in Guangdong province of China.

METHODSPCR-positive specimens were inoculated into embryonated chicken eggs and subtyped by conventional RT-PCR. All segments of the virus A/environment/Guangdong/2/2009 were sequenced, and phylogenetic trees were constructed and analyzed.

RESULTSThe genes of this virus belong to Eurasian-lineage avian viruses. The virus is a reassortant with the HA gene from an H2N2 virus and the NA gene from an H5N3 virus. The PB1, PB2, and NP genes were from an H4N6 virus, the PA was from an H3N8 virus, the M gene was from an H1N3 virus, and the NS gene was from an H10N6 virus.

CONCLUSIONA novel avian-origin reassortant H2N3 influenza virus was detected in a live poultry market. Its potential impacts and evolution should be closely monitored.

Animals ; China ; Ducks ; virology ; Genome, Viral ; Influenza A virus ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Phylogeny

To set up a new rapid method for the rapid determination of influenza virus H5N1 and H7N9 basing on the Multi-Analyte Suspension Array (MASA) technology. Sequence analysis and design of degenerate primers and specific probes were set in the comparison and analysis of H5, N1, H7 and N9 genes. In combination with MASA technology, these primers and probes were used for the determination of samples of H5N1 and H7N9 and other subtypes ( H1N1, PH1N1, H5N2, H3N2 and H9N2). We developed a rapid determination method. This method had high specificity and sensitivity that could detect H5N1 and H7N9 at one time, and could detect samples that containing 10 copies of H5N1 and H7N9. This determination method could be used for rapid determination of influenza virus H5N1 and H7N9 at one time.
Humans ; Influenza A Virus, H5N1 Subtype ; classification ; genetics ; isolation & purification ; Influenza A Virus, H7N9 Subtype ; classification ; genetics ; isolation & purification ; Influenza, Human ; virology ; Oligonucleotide Array Sequence Analysis ; methods

Global Health ; History, 20th Century ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; isolation & purification ; Influenza A Virus, H3N2 Subtype ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; history ; therapy ; virology ; Russia ; epidemiology

Global Health ; History, 20th Century ; Humans ; Influenza A Virus, H2N2 Subtype ; genetics ; isolation & purification ; Influenza A Virus, H3N2 Subtype ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; history ; mortality ; virology