Virological surveillance of pandemic (H1N1) 2009 virus and its genetic characteristics in Hunan Province, 2009-2011 / 病毒学报

To understand and master the dynamic variation of the pandemic influenza A (H1N1) 2009 in Hunan province from 2009 to 2011, and to know the genetic characteristics and drug resistance of the pandemic (H1N1) 2009 viruses. Throat swab specimens of influenza-like illness patients were collected from sentinel hospitals and tested for influenza by fluorescent PCR or virus isolation methods. Partial isolates were selected for sequencing. The sequences were used for phylogenetic analysis by MEGA 5. 05 software. From the 20th week of 2009 to the 52nd week of 2011, 17 773 specimens were tested. 3 831 specimens were influenza-positive with a positive rate of 21. 6%, of which 1 794 were positive specimens of pandemic (H1N1) 2009, accounting for 46. 8%00 of the influenza-positives. There were 2 epidemic peaks of pandemic (H1N1) 2009, which were in the 41st-53rd week of 2009 and the 1st-12nd week of 2011, respectively. The HA genes of 23 strains that were selected for sequencing had close relationship; the distribution of strains in the phylogenetic tree was basically in chronological order. The complete genome sequence analysis showed that all of 8 gene segments of 7 strains were homologous to the vaccine strain, and there was no gene reassortment. The HA amino acid sites of the 23 strains were highly similar to the vaccine strain (98. 2% - 100. 0% in homology), but all 23 strains had P83S, S203T and 1321V mutations. The 222 site mutation that may lead to enhanced virulence was found in the A/Hunan/YQ30/2009 strain. The mutation was D222E. There was no oseltamivir resistance mutation found in all strains. The pandemic (H1N1) 2009 in Hunan province from 2009 to 2011 had a bimodal distribution. There was no large-scale variation of virus genes. The clinical use of oseltamivir was still effective. Key words: Pandemic (H1N1) 2009; Surveillance; Genetic characteristics

Analysis on genetic characteristics of mumps virus strains circulating in Hunan province in 2011 / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To be acquainted with genetic characteristics and variation of mumps virus strains circulating in Hunan province.</p><p><b>METHODS</b>Mumps virus (MV) strains were isolated using Vero/ SLAM cells. The small hydrophobic protein (SH) genes of MV isolates were sequenced, and the sequences were analysed phylogenetically between the isolated strains and other reference mumps strains.</p><p><b>RESULTS</b>4 mumps virus strains were isolated from 16 specimens collected in 2011 from different regions of Hunan province. The genotype of isolated strains were supposed to be F type.</p><p><b>CONCLUSION</b>Genotype F is the main genotype of circulating strains in Hunan province in 2011 and there is no variation between genotype.</p>

Analysis of genetic features of influenza B virus in Hunan province from 2007 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the gene variations of influenza B virus isolated in Hunan province from 2007 to 2010.</p><p><b>METHODS</b>A total of 42 strains of influenza B virus,which were isolated in the Influenza Surveillance Network Laboratories in Hunan province between year 2007 and 2010, were selected for the study. The hemagglutinin 1 (HA1) and neuraminidase (NA) genes of the selected strains were amplified by RT-PCR, and the sequence of the purified product were detected and homologically compared with the sequence of influenza vaccine strains isolated from Northern Hemisphere by WHO during the same period. In addition, the phylogenetic trees were constructed to characterize the molecular features.</p><p><b>RESULTS</b>In the Victoria branch of the HA1 gene phylogenetic tree, the strains isolated from year 2007 to 2009 were included in the V1 sub-branch, as well as the vaccine strain Malaysia/2506/2004; the strains isolated in year 2010 were involved in the V2 sub-branch, similar to the vaccine strains Brisbane/60/2008. In the Yamagata branch,the strains isolated in year 2007 were in the Y1 sub-branch,different from the strains isolated between year 2008 and 2010, which were in the Y2 sub-branch, instead. All virus in NA gene phylogenetic tree were included in the Yamagata branch, indicated their Yamagata origin. The genetic sequence analysis of the 7 strains isolated in year 2010 revealed that the viruses were classified as genotype 2 and genotype 15. The results of homological comparison between HA1 molecule and the influenza vaccine strains recommended by WHO were as below: Victoria lineage, 98.6% - 99.1% in 2007, 98.6% - 99.1% in 2008, 98.1% - 99.1% in 2009, and 97.6% - 99.1% in 2010; and Yamagata lineage, 97.9% - 98.5% in 2007, 97.9% - 98.5% in 2009 and 97.9% - 98.2% in 2010. The major mutations of the strains isolated in year 2007 were found in sites R48K, K88R, P108A, D197N and S230G. While the major mutations of the strains isolated between year 2009 and 2010 were sited in K88R, S150I, N166Y, D197N and S230G.</p><p><b>CONCLUSION</b>The prevalent influenza B virus isolated in Hunan province from 2007 to 2010 has mutated and evolved continuously.</p>

Surveillance on the etiology and genetic characteristics of rabies in Hunan province, from 2008 to 2009 / 中华流行病学杂志

Objective To analyze the etiology of rabies in Hunan province and the genetic characteristics of rabies N gene isolated from 2008 to 2009.Methods Direct immunofluorescence assay (DFA) and nested PCR were employed to detect the monitoring samples including brain tissues of dogs and saliva,serum or urine which were collected in 2008 to 2009,from the rabies patients.Positive samples were sequenced by ABI3730 gene analyzer for the full length of the N gene target.The homology and hpylogeography of the rabies virus were analyzed after the phylogenetic tree was constructed by Blast,Clustal W and Mega 4.0 software.Results Of the 1451 tissue samples from the dogs' brain,31 were positive under DFA and the positive rate was 2.14％.The DFA positive samples were redeteeted by RT-PCR and the positive rate was 1.17％.56 samples of saliva,serum and urine samples were detected by RT-PCR from the rabies patients,with 3 positives and the positive rate was 5.36％.The length of nest PCR products were 255 bp.The rates of homology to the nucleotide and the amino acid of rabies N gene were 87.2％-87.9％ after compared to the pasture strain.The phylogenetic tree was successfully built and 20 strains isolated lately belonged to the rabies gene type Ⅰ.Conclusion The epidemic situation of human and dogs rabies in Human were relatively stable,with all the isolated rabies virus belonging to genotype Ⅰ,without any variation.

Serological survey of pandemic influenza A (H1N1) virus infection among population in Hunan Province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To understand the infection condition and analytical methods of Influenza A (H1N1) virus in the population of Hunan Province during different periods.</p><p><b>METHODS</b>Quick surveys on the positive rate of Influenza A (H1N1) virus hemagglutination inhibition (HI) test have been conducted for 5 times successively from November 2009 to March 2010 in 14 medical and health institutions of Changsha city, whose results were then compared with those from the sampling surveys of whole Hunan province.</p><p><b>RESULTS</b>2131 subjects were involved in this study; the total population standardized rates of antibody positive investigated for 5 times were 9.32% , 14.62%, 31.08%, 28.43% and 22.80% respectively; the population of 6-17-years-old has the highest rate of antibody positive; only 9.84% of the antibody positive subjects attributed to vaccine inoculation; there was no significant difference in the standardized positive rates between the quick serological surveys and the corresponding sampling survey of Hunan province (P > 0.05).</p><p><b>CONCLUSION</b>The positive rate of A (H1N1) virus antibody reached the peak in late January 2010; quick investigations in small region could be used to evaluate the infection prevalence during pandemic of infectious diseases.</p>

Molecular characterization of highly pathogenic avian influenza A(H5N1)viruses isolated from humans in Hunan province,2006-2009 / 中华流行病学杂志

Objective To understand the possible origins,genetic re-assortment and molecular characterization of 4 highly pathogenic avian influenza A(H5N1)viruses isolated from humans in Hunan province,between 2006 and 2009,Methods H5N1 PCR test-positive specimens were inoculated in embryonated eggs while H5N1 virus was isolated and genomes sequenced.Genome homology and genetic molecular characterization were analyzed by BLAST and MEGA 4.0.Results All gene segments of the 4 viruses were avian in origin.No re-assortment was found between avian influenza A(H5N1)viruses and human seasonal influenza viruses.Virnses that isolated from domestic poultry shared high similarity with the 4 human viruses in gene homology.Data from the whole genome phylogenetic analysis showed that the 4 viruses were in clade 2.3.4,while 2 viruses belonged to genotype V,and another 2 were new genotypes.Results from molecular characterization showed that amino acid sequences of HA cleavage site of the 4 viruses were PLRERRKR/G.All 4 viruses had A160T mutation in HA,a 20 amino acid deletion in the neuraminidase(NA)stalk at position 49-68,and a 5 amino acid deletion in the non-structural protein 1(NS1).Most sites in the HA molecules showed that the viruses preferentially bound to avian influenza virus receptor.However,T192I mutation that might enhance the α2,6-linked sialic acid human influenza receptor binding had emerged in HN/1/09 and HN/2/09.D701N mutation of PB2 that increased the virulence in mice was found in HN/1/08.Analysis on drug resistance gene amino acid showed that all 4 viruses were sensitive to amantadine and oseltamivir.Conclusion Highly pathogenic avian influenza A(H5N1)viruses isolated from humans in Hunan province from 2006 to 2009 were avian in origin,and the 4 viruses belonged to different genotypes.Some mutations that related to virulence and receptor binding positions had emerged in some of the strains.

Pathogenic diagnosis of an unexplained epidemic event of infectious diarrhea / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To determine the pathogen of an unexplained epidemic event of infectious diarrhea by laboratory diagnosis of suspected cases samples.</p><p><b>METHODS</b>28 samples from 28 suspected cases (22 fecal samples, 3 vomitus samples, 3 anus swab samples) were tested for Norovirus by RT-PCR. Sequencing and phylogenetic analysis were acomplished of 5 positive samples.</p><p><b>RESULTS</b>160 of 5694 population were ill with an attack rate of 2.81%. The peak period was 7-9, March. 14 of 28 samples were tested Norovirus positive.Sequencing and phylogenetic analysis showed Norovirus type GII/4 was the causative agent and it had highest identity (97. 9%) with epidemic strain 2006b.</p><p><b>CONCLUSION</b>The epidemic event ofinfectious diarrhea were caused by GII/4 Norovirus strains.</p>

Viral surveillance on rabies in Hunan province,in 2006 / 中华流行病学杂志

Objective To understand the source and distribution of rabies virus(RV)in Hunan province with viral surveillance in order to provide scientific measures for prevention and control on rabies.Methods Brain samples from healthy-looking domestic dogs were collected in the agricultural markets at the dist6cLs of high.middle,and lOW incidence rates and detected by direct Immunofluorescence assay (DFA).Positive samples would be further detected by RT-PCR and the surveillance samples were detected bv RT.PCR.The positive samples detected bv RT-PCR were sequenced with N gene.Results The infection rate of thosc healthy-looking domestic dogs with rabies virus was 2.78％in Hunan province in 2005.23 positive samples’N gene were sequenced and their similarities were 88.8％-100.0％.The results indicated that Hunan rabies virus N gene aberrance was mainly synonymous aberrance and did not CKITy obvious regional characteristics.The rabies virus were circulating among different districts in Hunan province,and the neighboring provinces such as Guizhou,Hubei，GuangxiComparison of immunity to measles between floating and local population,Jiangsu and Henan.There were no positive samples detected in salivary，blood and urine samples.There was one positive sample detected in two skin samples.Conclusion There are dogs infected with rabies virus found in Hunan province and this study showed that rabies virus detected in Hunan had a close genetic relationship with those rabies idcntified in other provinces,suggesting that study on the immunity and management of dog related rabies should be strengthened.

Laboratory diagnosis and molecular characterization of highly pathogenic avian influenza virus (H5N1) in human in Hunan Province in 2005-2006 / 病毒学报

To determine the etiologic agents of two atypical pneumonia human cases in Hunan Province in 2005-2006 and to study their pathogenic potential, the patients' respiratory tract samples and sera were collected. The respiratory tract samples were tested by real-time RT-PCR and RT-PCR methods, and the sera by hemagglutination-inhibition assay. Virus was isolated from case 2 and its genome was sequenced and analyzed. Results showed the H5 nucleic acid tests of two cases were positive. The H5-specific antibody titer of the convalescence serum of case 1 showed a 4-fold greater rise than that of the acute phase. And case 2's antibody titer of acute phase was negative. The two atypical pneumonia cases were confirmed as the avian influenza A (H5N1) infection cases. Viral strain A/Hunan/1/2006 was isolated from case 2. Phylogenetic and molecular analysis suggested that 8 gene segments of A/Hunan/1/2006 originated from avian viruses. And A/Hunan/1/2006 was similar with viruses isolated from avian in Hunan Province. The isolated virus did not recombine with human influenza viruses and no obvious variation was observed.

Virological surveillance on hemorrhagic fever with renal syndrome in Hunan province in 2006 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand the rate of viral carrying status among rodents as well as genotypes and distribution of Hantaviruses (HV) isolated in Hunan province.</p><p><b>METHODS</b>With DFA, the HV antigen in lung tissues of rodents was detected. The total viral RNA was extracted from the lung tissues of the HV infected rats and amplified with reverse transcrition-polymerase chain reaction (RT-PCR), using the HV genotype specific primers. The amplified genes were then sequenced and subjected to genotyping and homologic analysis.</p><p><b>RESULTS</b>The average density of rodents was 3.15% and the virus carrying rate among rodents was 1.31%. Data from genotype analysis showed that the HV isolated from seven lung specimens taken from Rattus norvgicus, Apodemus agraius, Mus musculus, Rattus flavipectus among indoor rodents in Shaodong and Liuyang belonged to HV type II (SEOV), and one isolated from Apodemus agraius in Shaungfen belonged to HV type I (HTNV) among outdoor rodents. Six strains were sequenced successfully and the homology between six srains was 88.3%-100%. The homology of HN1, HN2, HN4, HN6 came from Liuyang and the HN7 and HN8 from Shaodong were both 100% while the homology between L99 and the strains from Liuyang and Shaodong were 94.4% and 88.3% respectively.</p><p><b>CONCLUSION</b>HV type II (SEOV) and the HV type I (HTNV) were all existed in Hunan province while SEOV was the main genotype.</p>

Laboratory diagnoses of the first confirmed human case of avian influenza A (H5N1) in the mainland of China / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To determine the etiologic agent of an atypical pneumonia human case admitted to Xiangtan City hospital, Hunan Province in Oct. 2005.</p><p><b>METHODS</b>The patient's respiratory tract samples and serum were collected. Throat swabs were tested by microneutralization and hemagglutination-inhibition assays.</p><p><b>RESULTS</b>The results of nucleic acid detection of all respiratory samples were negative and virus isolation was also negative. The H5-specific antibodies of convalescence showed a 4-fold greater rise than acute phase.</p><p><b>CONCLUSION</b>The atypical pneumonias case was confirmed as the first human case of avian influenza A (H5N1) infection in the mainland of China.</p>