ABSTRACT
Objective@#To learn the concentration of target genes of severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2 ) and the influencing factors in the confirmed cases with coronavirus disease 2019 ( COVID-19 ) in Ningbo.@*Methods@#Demographic information and clinical diagnosis of COVID-19 cases reported in Ningbo from January 21 to February 20, 2020 were collected through China Disease Control and Prevention Information System. The Ct values of ORF1ab and N of the cases were collected through Ningbo Center for Disease Control and Prevention and designated hospitals, and analyzed in terms of gender, age, severity, clinical classification, source of case, sampling time and specimen type. @*Results@#There were 157 confirmed COVID-19 cases, including 56 males ( 35.67% ) and 101 females ( 64.33% ). Sixty-seven cases ( 42.68% ) aged between 40 and 60 years old. The Ct values of ORF1ab and N in females were 29.96±5.28 and 30.38±4.90, which were higher than 27.56±4.94 and 28.03±4.88 in males ( P<0.05 ). The Ct values of ORF1ab and N were the lowest when sampled at 1-7 days after onset ( P<0.05 ), which were 27.84±4.80 and 28.35±4.65. The Ct values of ORF1ab ( rs=0.288, P=0.001 ) and N ( rs=0.296, P=0.001 ) were positively correlated with sampling time. The Ct values of ORF1ab in pharyngeal swab and sputum were 29.19±4.85 and 28.74±6.40, the Ct values of N in pharyngeal swab and sputum were 29.61±4.60 and 29.22±6.10, both without significant differences between different samples ( P>0.05 ). @*Conclusions@#Sampling time has a great influence on the Ct values of ORF1ab and N of SARS-CoV-2.
ABSTRACT
OBJECTIVE: To investigate the epidemiological characteristics of influenza B viruses and explore the genetic evolution characteristics of the hemagglutinin(HA) and neuraminidase(NA) genes of local isolated strains in Ningbo, Southeast China, during 2010 to 2012. METHODS: Respiratory specimens from 3440 cases of patients with influenza-like illness(ILI) during 2010 to 2012 were collected in for virus isolation. And the 628 sera samples were collected in 2010 from the healthy community population to detect the HI antibody level against the local isolated virus.For phylogenetic analysis, the fragments of HA and NA genes were amplified and sequenced from strains isolated in different years. The association between evolution of HA and epidemiological characteristics were analyzed. RESULTS: A total of 109 strains of influenza B virus were isolated, including 102 (93.6%) Victoria-lineage strains and 7 (6.4%) Yamagata-lineage strains. Positive rates of HI antibody against Victoria-lineage strains and Yamagata-lineage strains were 51.1% (321) and 47.8% (300), respectively (χ(2) = 1.405, P > 0.05) among the 628 sera samples. The phylogenetic analysis showed that all HA fragments of isolated strains clustered the same branch with Malaysia/2506/2004 while the NA genes formed different branches. Compared with Brisbane/60/2008 strain, there were 1 to 5 Amino acid mutations in HA domain, and more mutations were detected in NA domain, ranged from 6 to 16 sites. The genetic evolution of NA in Victoria-lineage strains were faster compared with HA. CONCLUSION: The genetic evolution rates of NA genes were faster than that of HA genes in the local circulated Victoria-lineage viruses during 2010 to 2012;The comprehensive analysis of HA and NA fragments were more reliable and sensitive on surveillance of genetic evolution of influenza B viruses.
Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza B virus/genetics , Influenza, Human/virology , Neuraminidase/genetics , China/epidemiology , Genetic Variation , Humans , Influenza B virus/classification , Influenza B virus/isolation & purification , Influenza, Human/epidemiology , Phylogeny , RNA, ViralABSTRACT
OBJECTIVE: To understand the status of infants infected with influenza viruses after switch over of dominant strain in the summer of 2006. METHODS: Two groups of infants serum were collected and to be detected the antibodies of influenza viruses which the infants experienced two peaks of influenza A H1N1 circulation in the age of 3-4 and 10-11 months old and the infants only experience one circulation in 5-6 months old. RESULTS: The antibody of influenza A H1N1 viruses was 31.47% in the infants who experience two circulations in 3-4 months and 10-11 months old and was 26.42% which only experience circulation in the 5-6 months old. There were no significant difference between 2 groups (chi2 = 1.207, P > 0.05). CONCLUSION: The group of 13 months age of infants were rarely infected influenza virus in the first time exposure at the age of < or =4 months due to maternal antibodies protection. Whenas, the group of 8 months age who were exposed at the age of > or =5 months, were more easier infected the influenza virus than the group of 13 months age in the first time exposure at the age of < or =4 months.
