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Objective:To analyze the variation and evolution characteristics of hemagglutinin (HA) and neuraminidase (NA) genes of influenza B virus circulating in Jining from 2017 to 2020.Methods:Throat swab specimens were collected from patients with influenza-like symptoms in sentinel hospitals and influenza outbreaks in Jining from 2017 to 2020 and tested for influenza B virus nucleic acid. After virus isolation, 20 representative strains of influenza B virus were selected to sequence the full length of HA and NA genes. Phylogenetic trees were constructed and the molecular characteristics were analyzed using bioinformatics software. Results:A total of 4 575 specimens were collected and 842 of them were positive for influenza virus, including 398 (8.7%, 398/4 575) influenza B virus-positive specimens. The positive rate of influenza B virus was 47.27% (398/842). The isolated influenza B virus strains of Victoria (BV) and Yamagata (BY) lineages from 2017 to 2020 shared 98.7%-98.8% and 98.5%-99.1% homology in HA gene with vaccine strains, respectively. The BV lineage strains isolated from 2018 to 2020 belonged to Victoria clade 1A branch and the BY lineage strains isolated from 2017 to 2018 belonged to Yamagata clade 3 branch. Mutations were detected in several antigenic sites, but not in the sites related to NA inhibitor resistance. Conclusions:Mutations in several antigenic sites caused antigenic changes in influenza B virus of BV and BY lineages, which might be related to the outbreaks of influenza B virus infection in Jining during 2017 to 2020.
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Objective To understand the changes of schistosomiasis epidemic situation,so as to provide the evidence for for?mulating schistosomiasis control strategy in the Hexi reservoir area. Methods From 2012 to 2015,Xinyuan Village,Meishan Town in the north entrance of Hexi reservoir was selected as a monitoring site. According to the requirements of the monitoring program of schistosomiasis surveillance in Zhejiang Province,the Schistosoma japonicum infection was investigated by using the serological screening(IHA),and the basic situation of the surveillance site was also investigated. Results From 2012 to 2015,167 environments(21.68 hm2)were surveyed,and 2 slices(0.1 hm2)were found with Oncomelania hupensis snails. The detection rate of frames with snails was 0.12%,and the living snail density was 0.0192 snails per 0.1 m2. Totally 374 snails were dissected and no schistosome infected snails were found. A total of 970 local residents and 8 748 mobile people were investigated with the serological tests,and no schistosome infected people were found. In addition,3 085 cattle were investigated and no in?fected ones were found. Conclusion The schistosomiasis epidemic situation is stable in the Hexi reservoir area,but we still should strengthen the monitoring of imported source of infection and snail status,and increase the efforts of environmental trans?formation.
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objective To understand the status of Oncomelania hupensis snail distribution and diffusion in main drainages of Hexi Reservoir and evaluate the snail control effect of the schistosomiasis control engineering of Hexi Reservoir. Methods The O. hupensis snails were investigated by using the straw curtain method and fishing net method in different areas of the main drainages of Hexi Reservoir and the results were analyzed. Results A total of 1 800 straw curtains were used and 37 snails were found in Naxi stream. Totally 5 870 kg floats were salved and no snails were found. Conclusion The schistosomiasis con?trol engineering of Hexi Reservoir is effective in the prevention of the snail diffusion but there are still snails in the upstream. Therefore the snail surveillance and control need to be strengthened.