[Epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023]

Objective: To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023. Methods: The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed. Results: A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M (Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant (P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age (P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion: Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

[Analysis of common viral infection in surveillance cases of febrile respiratory syndrome in 9 provinces of China from 2009 to 2021]

Objective: To understand the common viral infection among the surveillance cases of fever respiratory syndrome (FRS) in nine provinces in China. Methods: The research data were obtained from nine provinces (Anhui, Beijing, Guangdong, Hebei, Hunan, Jilin, Shandong, Shaanxi and Xinjiang) in the "Infectious Disease Surveillance Technology Platform Information Management System" of the Chinese Center for Disease Control and Prevention from January 2009 to June 2021. Finally, 8 243 FRS cases with nucleic acid detection results of eight viruses [human influenza virus (HIFV), human respiratory syncytial virus (HRSV), human adenovirus (HAdV), human parainfluenza virus (HPIV), human rhinovirus (HRV), human metapneumovirus (HMPV), human coronavirus (HCoV) and human Boca virus (HBoV)] were included in the study. The χ² test/Fisher exact probability method was used to analyze the difference of virus detection rate in different age groups, regions and seasons. Results The M (Q₁, Q₃) age of 8 243 FRS cases was 4 (1, 18) years old, and 56.56% (4 662 cases) were children under 5 years old. Males accounted for 58.1% (4 792 cases) of all cases. All cases were from outpatient/emergency department (2 043 cases) and inpatient department (6 200 cases). The virus detection rates of FRS cases from high to low were HRSV, HIFV, HPIV, HRV, HAdV, HMPV, HCoV and HBoV. Two or more viruses were detected simultaneously in 524 cases, accounting for 15.66% of virus-positive cases. The difference of the virus detection rate in different age groups was statistically significant (all P values<0.05), and the virus detection rate in children<5 years old was higher (49.96%). The positive rate of any virus in south China was higher than that in north China (P<0.001). The virus-positive FRS cases were detected throughout the year. The detection rate of HRSV was higher in autumn and winter. The detection rate of HIFV was higher in winter. The detection rate of HMPV was higher in winter and spring. The detection rates of HPIV, HRV, HCoV and HBoV were higher in summer and autumn, while there was no significant difference in the detection rate of HAdV in different seasons. Compared with 2009-2019, the detection rate of any virus in 2020-2021 decreased from 41.37% to 37.86%. The detection rate of HIFV decreased sharply from 10.62% to 1.37%. The detection rate of HPIV decreased from 8.24% to 5.88%. The detection rate of HRV and HBoV increased from 5.43% and 1.79% to 9.67% and 3.19%, respectively. Conclusion: HRSV and HIFV infections are more common among FRS cases in nine provinces in China from 2009 to 2021, and the epidemiological characteristics of eight common respiratory viruses vary in different age groups, regions and seasons.

[Genotype and genetic characteristics of human respiratory syncytial virus circulating in Quanzhou, 2018-2019]

Objective: To study the prevalence and genetic characteristics of human respiratory syncytial virus (HRSV) in Quanzhou city, from 2018 to 2019. Methods: A total of 141 throat swabs were collected from children patients of lower respiratory tract infection in Quanzhou children Hospital, Fujian Province from November 2018 to May 2019. RT-PCR was used to amplify the 3 'end of G gene HRSV. Sequencer 5.0 and MEGA5.05 softwares were used for sequence editing, phylogenetic tree construction and genotyping analysis. Results: Twenty-five samples were positive for HRSV. Seventeen samples succeeded to obtain the target gene, including 13 of HRSVA and 4 of HRSVB. Two genotypes were identified: ON1 genotype (13 samples, HRSVA) and BA9 genotype (4 samples, HRSVB). Five strains of ON1 genotype sequences were clustered with the ON1 sequences prevalent in Beijing, Changchun and Zhejiang from 2012 to 2015 (cluster1); one strain (FJ19-02) was clustered with the sequences of ON1 genotype circulating in many regions of China from 2012 to 2015 (cluster2); Seven strains were clustered independently (cluster FJ). FJ18-02, FJ19-14 and FJ19-15 of HRSVB were clustered with the BA9 genotype sequences prevalent in Changchun, Jilin Province in 2015, while FJ19-13 was closely related to the BA9 genotype sequences prevalent in Guangzhou and Zhejiang Province in 2013. Both the ON1 and BA9 genotypes showed variations of nucleotide and amino acid in 72 and 60 insertion segments. Amino acid mutation (H266L) only occurred among the sequence of cluster-FJ, and the mutations of H261Q and Q265L only appeared in strain FJ19-13. Conclusion: BA9 and ON1 genotypes were prevalent in Quanzhou city, from 2018 to 2019. Cluster-FJ was a newly discovered independent transmission chain, which may continue to circulate in local Quanzhou area.

[Genetic characterization of varicella zoster virus in Jilin province in 2014, China]

OBJECTIVE

To clarify the genotype of wild-type strains of varicella zoster virus (VZV) in Jilin province in 2014, and to discriminate between v-Oka vaccine strains and wild-type strains.

METHODS

Vesicle fluid and throat swab samples were collected from 13 individuals with suspected VZV in Jilin province from January to December 2014. Viral DNA was extracted, the fragments of 15 open reading fragments (ORFs) were amplified by polymerase chain reaction (PCR), and viral genotypes were determined by single nucleotide polymorphisms (SNP). PCR restriction fragment length polymorphism (RFLP) was used to distinguish between wild-type strains and v-Oka vaccine strains. The results were analyzed with MEGA5 software, using the VZV reference strain sequences from GenBank.

RESULTS

The 13 suspected samples included 5 males and 8 females, aged 11-27 years (mean: (16.69±5.48) years). Sampling was performed on days 0 to 3 of suspected infection. VZV strains were detected in 8 samples, all belonging to Clade 2. There was a synonymous mutation (T>C) in SNP18082 compared with the v-Oka vaccine strain. Analysis of PCR-RFLPs showed that all 8 positive samples were wild-type strains (PstⅠ(+)BglⅠ(+)SmaⅠ(-)).

CONCLUSIONS

The study revealed that the VZV strains circulating in Jilin province in 2014 were wild-type strains belonging to Clade 2.

Reversible valence tautomerism induced by a single-shot laser pulse in a cobalt-iron Prussian blue analog

Reversible valence tautomeric conversion induced by a single-shot laser pulse (8 ns duration) with a photon excitation energy of 2.38 eV has been observed in Na0.36Co1.32Fe(CN)(6).5.6H(2)O. A photoswitching process with accompanying magnetization and color changes was successfully achieved within the pulse duration at high temperature (above 200 K) in a thermal hysteresis loop. This unusual photoeffect originates from an optical charge transfer between Fe and Co atoms and evolves due to a cooperative interaction among the local photoexcited sites.