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<p><b>OBJECTIVE</b>To investigate the prevalence of influenza virus infections in children in 2006 using the real-time PCR method.</p><p><b>METHODS</b>(1) Consulting the most conserved sequence NP gene of influenza virus, after comparing with the NP gene sequences of influenza virus in GenBank, one pair of specific primers and one TaqMan probe were designed for each subtype of influenza virus by the software Primer Express. The sensitivity of influenza was evaluated by testing known positive samples which had been two-fold diluted. The specificity of real-time PCR for influenza virus detection was assessed by cross testing 60 isolates of influenza A, 16 isolates of influenza B, and by testing a variety of other respiratory viruses positive samples; (2) 281 nasopharyngeal aspirate samples were detected by real-time PCR and virus isolation; (3) the 12 301 specimens from the patients of Guangzhou Children's Hospital were tested by using the real-time PCR method. Furthermore, the real-time PCR reagent was evaluated by comparing with the result of virus isolation.</p><p><b>RESULTS</b>(1) The sensitivity of real-time PCR developed in this study for influenza A detection was 1:2(22) and for influenza B was 1:2(20) in two-fold serially diluted way. (2) No positive results were found in cross testing of other viruses positive specimens. (3) Influenza virus was detected from 1687 cases (13.71%) out of the 12 301 cases, including 773 cases (45.8%) positive for subtype A and 914 cases (54.2%) positive for subtype B; 455 out of 525 (86.7%) of influenza B positive specimens and 70 out of 525 (13.3%) of influenza A (H1N1) positive specimens were from patients seen during January to April; 419 out of 1118 (37.5%) specimens positive for influenza B and 699 out of 1118 (62.5%) specimens positive for influenza A (H1N1) were from patients seen from May to August. Influenza virus could be identified from 1380 samples by the methods of virus isolation, accounting for 81.80% of the 1687 positive samples detected by real-time PCR. All the influenza virus subtype A was H1N1.</p><p><b>CONCLUSION</b>The real-time PCR method developed in this study was sensitive and specific for detecting influenza A and B in clinical specimens. During 2006, influenza A and influenza B co-circulated. The predominant virus was influenza B from January to April, peaking in April. Influenza A (H1N1) prevailed from May to August, with the peak in June.</p>
Subject(s)
Child , Humans , China , Epidemiology , Epidemics , Influenza A Virus, H1N1 Subtype , Influenza, Human , Epidemiology , Virology , Polymerase Chain Reaction , Methods , Prevalence , RNA, Viral , Sensitivity and SpecificityABSTRACT
Objective To investigate the pathogenesis of peripheral blood mononuclear cells(PBMC) nuclear factor kappa-?B(NF-?B) in children with primary nephritic syndrome(PNS) and the effect of astragalus on the activity of NF-?B.Methods Twenty-five children with PNS and 20 normal children were studied.Isolated PBMC were separated from 5 mL venous blood in asepsis condition.NF-?B stimulator,NF-?B inhabitor and astragalus were added into the different tubes of PBMC,respectively.The nuclear protein was extracted from the pellets and the optical density(A) values of nuclear protein was measured by enzyme-linked immunosorbent assay(ELISA).Results The activity of PBMC NF-?B in PNS group was higher than that in normal group(P0.05).Astragalus could decrease the activity of PBMC NF-?B which had been stimulated by interleukin-1?(IL-1?)(P
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6-11 years old were 9.67%, 6.81%, 3.49% and 0.80%, respectively.Furthermore, the infection rates between each two age stages were significantly different(Pa0.05).4.Infection rates in 2005,2006 and 2007 were 4.0%, 8.92%, 8.85%,respectively.Infection rates between 2005 and 2006,2007 were significantly different(Pa
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Objective To explore the epidemics of influenza viruses in Guangzhou area from 1998 to 2003. Methods The specimens for viral isolation were taken with swabs from children's throats and the material was inoculated into the MDCK cells and were incubated at 33 ℃ The supernatant of MDCK cells culture was tested with hemagglutination test. Results Influenza viruses were isolated from 264 of 3444 children; total positive rate of influenza virus isolation was 7.6%. The positive rate of influenza viruses was 16.8% in 1998; the prevailing strain of influenza viruses was H3N2. The influenza viruses isolation rate was 7.4% in 1999;the positive rate was 8.4% ; HIN1 occurred in 2000, the positive rate was 3.8%. H3N2 did not occur in 2001; the positive rate was 7.3% ; influenza B viruses was the prevailing strain in 2002; the positive rate was 1.7% in 2003. Influenza B viruses was Yamagata like strain from 1998 to 2001, Victoria like strain from 2002 to 2003. H9N2 avian influenza virus was isolated from a child. Conclusions Influenza was prevalent in Guangzhou in 1998, but not prevalent from 1999 to 2003. Most of influenza B viruses were Yamagata strain. There were cases avian influenza caused by H9N2 in 1999.