ABSTRACT
<p><b>OBJECTIVE</b>To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.</p><p><b>METHODS</b>An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an. Clinical specimens, cloacal swabs, and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction (RT-PCR) for H7N9 virus. The positive samples were subjected to further RT-PCR and genome sequencing. The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.</p><p><b>RESULTS</b>Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever (>38.0 °C) and headaches. Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure. Phylogenetic analysis revealed that all novel H7N9 viruses, including Huai'an strains, could be classified into two distinct clades, A and B. Additionally, the diversified H7N9 virus circulated in live poultry markets in Huai'an. Interestingly, the common ancestors of the Huai'an H7N9 virus existed in January 2012. The mean nucleotide substitution rates for each gene segment of the H7N9 virus were (3.09-7.26)×10-3 substitutions/site per year (95% HPD: 1.72×10-3 to 1.16×10-2).</p><p><b>CONCLUSION</b>Overall, the source of exposure of human H7N9 cases in Huai'an was live poultry market, and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.</p>
Subject(s)
Adult , Aged , Aged, 80 and over , Animals , Female , Humans , Male , Middle Aged , China , Epidemiology , Evolution, Molecular , Influenza A Virus, H7N9 Subtype , Classification , Genetics , Influenza in Birds , Epidemiology , Virology , Influenza, Human , Epidemiology , Virology , Molecular Epidemiology , Phylogeny , Poultry , PrevalenceABSTRACT
To gain more insights into epidemiologic characteristics and genotype of hantavirus in Apodemus agrarius in Changbai Area. Complete hantavirus S segment sequences were amplified by RT-PCR and sequenced. The phylogenetic trees were constructed for analysis of genetic characters of hantavirus. A total of 58 Apodemus agrarius were trapped in the epidemic areas, and complete hantavirus S segment sequences were obtained from 4 lung samples of these rodents (6. 90%0). Phylogenetic analysis of the four S segment sequences indicated that all viruses isolated from Apodemu sagrarius were closely related to genotype 6 of Hantaan virus (95. 8%-96. 3%, nucleotide identity; 98. 6%-99. 5%, amino acid identity), all of them had a specific S387 different from other genotypes of Hantaan virus.