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Objective:To analyze the molecular evolution characteristics of HA and NA genes of influenza B/Yamagata (BY) and influenza B/Victoria (BV) lineage viruses in Guizhou Province, aiming to provide reference for scientific prevention and control of influenza. Methods:The prevalence of various types of influenza viruses in Guizhou Province from 2017 to 2021 was analyzed. The nucleic acid of influenza B viruses was extracted, and then the HA and NA genes were amplified by RT-PCR. Fourteen strains were sequenced and the sequences of 83 strains were obtained from GISAID. Homologies between the 97 influenza B viruses as well as the phylogenetic characteristics and amino acid site variations were analyzed. Results:Influenza A, BY and BV lineage viruses co-circulated in Guizhou Province and BV lineage was the predominant type. The homologies of HA and NA genes were 98.7%-99.4% and 98.4%-99.6% between BY lineage viruses and the reference vaccine strain B/PHUKET/3073/2013. BV lineage viruses shared 98.3%-99.3% and 98.9%-99.6% homologies with the reference vaccine strain B/Colorado/06/2017. The BY lineage strains in Guizhou Province mainly belonged to Y3 genetic group with HA gene in two branches of Y3-H1-2 and NA gene in three branches of Y3-N1-3. Three reassortant strains were found in Y3 clade. The isolated BV lineage strains mainly belonged to V1A-2 genetic group with HA gene in four branches of V1A-2 H1-4 and NA gene in five branches of V1A-2 N1-5. Twenty reassortant strains were found in V1A-2 clade and no inter-lineage reassortants were found. Analysis of variations at key amino acid sites showed that there was no mutation at epitopes in Y3 genetic group. However, there were point mutations at four main epitopes and a shift mutation in 190 helix in V1A-2 genetic group. There was no mutation in drug resistance sites. Conclusions:Various types of influenza viruses circulated in Guizhou Province. The homology between influenza B viruses and vaccine strains was decreasing. Different branches of HA and NA genes had been evolved and various forms of mutations were detected in the sequences. Intra-lineage reassortant strains and new varieties emerged. Surveillance of influenza B viruses should be strengthened.
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Objective:To understand the genetic variation and the prevalence of H9N2 subtype avian influenza virus in Guizhou province, and to provide the scientific evidence for the prevention and control of avian influenza virus.Methods:The results of AIV detection in live poultry market(LPM) environment in Guizhou province from October 2018 to March 2019 were statistically analyzed, RNAs were extracted and sequenced from the HA genes of 13 samples of H9N2 positive screened by real-time PCR. Then the homology, the genetic evolution and the mutations of important amino acid were analyzed by bioinformation softwares. Results:The positive rate of AIV was 52.2% and the positive rate of H9N2 was 83.7% in LPM environment. The homology between nucleotides of the HA gene of 21 strains ranged from 91.6% to 100.0%, and the homology between amino acids of the HA gene ranged from 91.0% to 100.0%. All strains belonged to Y280 sublineage and G57 genotype. Key sites analysis showed that they had a common motif PSRSSRGLF and LSRSSRGLF at the cleavage site, which indicated that they were lentogenic and low pathogenic strains. Mutations H191N, E198T/A and Q234L at the receptor binding sites in the HA was found in 21 strains, while indicated the viruses had the potential to bind human-like receptor. The analysis results of glycosylation motifs showed that all 21 strains had 7 glycosylation sites, but had a site deletion at amino acid site 218 and an addition at 313.There was no significant mutation in the key site compared with the human infected strains. Conclusions:The detection rate of AIV in LPM environment in Guizhou province was high, and the pollution was very serious, and H9N2 subtype is the main subtype, All H9N2 subtype AIVs belonged to Y280 sublineage and G57 genotype, and they were low pathogenic avian influenza viruses in Guizhou province, but the genetic gap were widening and mutations of key amino acid site might enhance susceptibility and pathogenicity to human beings. Hence, It is necessary to strengthen the surveillance of molecular characteristic variation of H9N2 subtype AIV.
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Objective To compare the efficacy of uniform multi-drug therapy (UMDT) versus routine multi-drug therapy (RMDT) for the treatment of multi-bacillary (MB) leprosy patients based on bacterial index changes and frequencies of leprosy reaction.Methods This study recruited newly diagnosed leprosy patients after taking informed consent in three districts of Guizhou province as well as in one district of Yunnan province from November 2003 to June 2005.The patients received 6-month UMDT or 2-year RMDT.Clinical follow up and bacterial reexamination were carried out once a year.Changes of bacterial index (BI) and frequencies of leprosy reaction were compared between the patients receiving RMDT and UMDT.Results A total of 166 patients received UMDT and 170 received RMDT in this study.Among the UMDT-treated patients,114 were skin smear positive,and 83 had been followed up for 42 months; of the RMDT-treated patients,149 underwent all the bacterial examinations during a 48-month follow up.The mean bacterial index decreased from 2.84 before treatment to 0.33 at the end of the 42-month follow up in the 83 patients,and from 2.55 to 0.26 at the end of the 48-month follow up in the 149 patients,with no significant difference in the changes of bacterial index between the two groups (t =0.77,P ＞ 0.05).Bacterial index became negative in 73.5％ (61/83) of the UMDT-treated patients and in 77.2％ (115/149) of the RMDT-treated patients (x2 =0.40,P＞ 0.05)at the end of follow up.During the follow up peroid,the incidence of type Ⅰ leprosy reaction was 14.6％ (13/89) in the UMDT group,significantly higher than that in the RMDT group (3.4％ (5/149),x2 =10.08,P＜ 0.01 ).Conclusions There is no significant difference in mean bacterial index changes and bacterial clearance rate during the follow up peroid between UMDT- and RMDT-treated patients.The incidence of type Ⅰ leprosy reaction is higher in the UMDT group than in the RMDT group,and further investigation is needed to clarify the mechanisms underlying the phenomenon.
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Objective To assess the efficacy of 6-month uniform multidrug therapy in various types of leprosy. Methods A field trial was conducted among 166 patients with different types of leprosy. All patients were treated with uniform multidrug therapy for 6 months, then followed up for 2 years. Clinical and bacterio-logical improvements were evaluated. Results Among the 166 patients, 31 dropped out due to various reasons,and 135 completed the 6-month treatment and 2-year follow-up. Among the 135 patients, 45 (33.3%) were skin smear negative, and the other smear-positive 90 had an average bacterial index (BI) of 2.91±1.45 (range: 0.1-6.0) before treatment. At the end of the 2-year follow-up, the 45 skin smear-negative patients showed 93.3% improvement in skin lesions and 80.0% improvement in nerve impairments, and the smear-posi-tive 90 patients showed 95.6% improvements in skin lesions and 77.8% improvement in nerve impairments.Skin smear turned negative in 49 (54.4%) out of the smear-positive 90 patients with the average BI declining to 0.66±0.99. The annual decrease in BI reached 0.9 during the first 2.5 years after the beginning of treat-ment. Twenty-five patients developed leprosy reaction during the follow-up, including 13 cases of type Ⅰ leprosy reaction and 12 cases of type Ⅱ leprosy reaction. Relapse was noted in 1 patient with muhibacillary leprosy 13 months after the termination of treatment. Conclusions The short-term efficacy of uniform multidrug therapy is similar to that of 2-year treatment with routine multidrug therapy. However, further studies are required to survey the incidence of leprosy reaction and relapse in patients treated with uniform multidrug therapy.