Epidemiological characteristics of human adenovirus 2, 3 and 7 genetypes in hospitalized children with respiratory infection in a hospital of pediatric in Hebei Province from 2018 to 2020 / 中华预防医学杂志

Objective: To investigate the epidemiological characteristics of human adenovirus (HADV) 2, 3 and 7 in hospitalized children with respiratory infection. Methods: A total of 25 686 children with respiratory infection hospitalized at Children's Hospital of Hebei Province from January 2018 to December 2020 were retrospectively included.Deep sputum or nasopharyngeal aspirates of those children were collected. Then thirteen common respiratory pathogens were detected by multiplex PCR. 510 HADV positive specimens were randomly selected via random number and classified for type 2, 3 and 7 using a multiplex real-time quantitative PCR. SPSS 21.0 software was used to perform all of the statistical analyses. Enumeration data were expressed by frequency and percentage. χ2 test was used for comparison between groups. Results: The HADV-positive rate was 7.99% (2 052/25 686). Children at age 3-<6 years had the highest HADV-positive rate (11.44%). The HADV-positive rate in 2019 was highest (10.64%). Among the 510 HADV-positive specimens, the proportion of type 3 was the highest (31.16%), followed by type 7 (21.37%) and type 2 (11.18%). The rate of type 2 in 2019 was significantly lower than that in 2018 and 2020 (χ2=8.954 and 16.354; P=0.003 and <0.01), while the rate of type 3 was significantly higher than that in 2018 and 2020 (χ2=5.248 and 4.811; P=0.022 and 0.028). The rate of type 2, type 3 and type 7 were lowest in winter, spring and autumn, respectively. The rate of type 2 increased significantly in autumn and the rate of type 3 and type 7 increased significantly in winter.The co-detection rate of HADV with other respiratory pathogens was 43.33%(221/510). Among, the co-detection rate of type 3 was highest (47.32%), and the co-detection rate of type 2, 3 and 7 was significantly higher than the alone detection rate (χ2=20.438, P<0.01; χ2=42.105, P<0.01; χ2=27.573, P<0.01).The proportion of severe pneumonia in children with type 7 positive (15.89%) was higher than that in children with non-type 7 positive (8.23%) (χ2=5.260, P=0.022). Conclusion: HADV is one of the important pathogens of children with respiratory infection in Children's Hospital of Hebei Province. The susceptible population of HADV is preschool children aged 3 to 6 years. HADV often co-detects with other respiratory pathogens. Type 3 and 7 is likely to be the dominant genotypes in this region, and type 7 may be one of the risk factors of severe pneumonia in children.

VSITA, an Improved Approach of Target Amplification in the Identification of Viral Pathogens / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Unbiased next generation sequencing (NGS) is susceptible to interference from host or environmental sequences. Consequently, background depletion and virome enrichment techniques are usually needed for clinical samples where viral load is much lower than background sequences.</p><p><b>METHODS</b>A viral Sequence Independent Targeted Amplification (VSITA) approach using a set of non-ribosomal and virus-enriched octamers (V8) was developed and compared with traditionally used random hexamers (N6). Forty-five archived clinical samples of different types were used in parallel to compare the V8 and N6 enrichment performance of viral sequences and removal performance of ribosomal sequences in the step of reverse transcription followed by quantitative PCR (qPCR). Ten sera samples from patients with fever of unknown origin and 10 feces samples from patients with diarrhea of unknown origin were used in comparison of V8 and N6 enrichment performance following NGS analysis.</p><p><b>RESULTS</b>A minimum 30 hexamers matching to viral reference sequences (sense and antisense) were selected from a dataset of random 4,096 (46) hexamers (N6). Two random nucleotides were added to the 5' end of the selected hexamers, and 480 (30 × 42) octamers (V8) were obtained. In general, VSITA approach showed higher enrichment of virus-targeted cDNA and enhanced ability to remove unwanted ribosomal sequences in the majorities of 45 predefined clinical samples. Moreover, VSITA combined with NGS enabled to detect not only more viruses but also achieve more viral reads hit and higher viral genome coverage in 20 clinical samples with diarrhea or fever of unknown origin.</p><p><b>CONCLUSION</b>The VSITA approach designed in this study is demonstrated to possess higher sensitivity and broader genome coverage than traditionally used random hexamers in the NGS-based identification of viral pathogens directly from clinical samples.</p>