ABSTRACT
<p><b>OBJECTIVE</b>To study the epidemic situation and dominant strain of influenza in children with acute respiratory infection (ARI) during Flu season from Oct. 2005 to Mar. 2006 in Taiyuan.</p><p><b>METHODS</b>Madin-darby canine kidney (MDCK) cell culture and hemagglutination inhibition (HI) assay were used to isolate and identify type A influenza viruses (H1N1 and H3N2) and B influenza viruses from clinical samples collected from outpatients who visited the Department of Pediatric because of ARI from Oct. 2005 to Mar. 2006. Oct. 2005 and Mar. 2006, we collected 415 blood samples from children and adults to detect the influenza virus antibody titers by HI test to exclude respiratory diseases.</p><p><b>RESULTS</b>7 strains of H1N1 were isolated from 87 clinical specimens, with a positive rate of H1N1 as 8.04%. Out of 415 blood samples being collected, the positive rates and the geometric mean titer of H1N1 antibody Mar. 2006 were significantly higher in 0-3, 3-7 and 7-18 year-olds than Oct.2005.</p><p><b>CONCLUSION</b>H1N1 epidemic influenza did occur among children in winter and spring of 2005--2006 in Taiyuan city.</p>
Subject(s)
Adolescent , Animals , Child , Child, Preschool , Dogs , Humans , Infant , Antibodies, Viral , Blood , Cell Line , China , Epidemiology , Hemagglutination Inhibition Tests , Influenza A Virus, H1N1 Subtype , Influenza A Virus, H3N2 Subtype , Influenza B virus , Influenza, Human , Epidemiology , Population SurveillanceABSTRACT
<p><b>BACKGROUND</b>To find out the timing of serologic responses after illness onset and distribution of IgG antibody to SARS-CoV in SARS cases of transmission chain or non-transmission chain.</p><p><b>METHODS</b>The IgG and IgM antibodies to SARS-CoV were tested by indirect ELISA in serum samples from 301 clinically diagnosed SARS cases.</p><p><b>RESULTS</b>Totally 158 SARS cases were involved in 15 chains of transmission. The positive rates of SARS-CoV IgG in those chains were 85.70%-100.00% and the overall rate was 94.30% (149/158). The chain of transmission could spread to four generations, but the SARS cases were reduced with increase of generations. There was no significant difference among positive rates of SARS-CoV IgG for generations, Chi square=5.11, P greater than 0.05. The positive rate of SARS-CoV IgG in cases who were not in chain of transmission was 12.59%(18/143) which was statistically significantly different from that of cases in chain of transmission, Chi square=199.64, P less than 0.001. During days 0-7,8-14,15-21,22-30 after onset, the cumulated positive rate of SARS-CoV IgG was 16.67%, 40.00%, 70.00% and 93.10%, respectively, then was kept at the level above 90% and lasted for 217 days. The cumulated positive rate of SARS-CoV IgM during days 0-7 after onset was the same to that of IgG. During days 8-14, 55.17% of cases had seroconversion for IgM which reached a peak (86.96%) during days 21-30. Then the rate rapidly declined.</p><p><b>CONCLUSION</b>More than 94% of cases with SARS could produce IgG antibody when they were infected by SARS-CoV. Detecting SARS-CoV IgG could provide a diagnostic evidence for case confirmation. SARS-CoV IgG appeared as early as 7 days after onset and reached the peak at about weeks 4. Then the high rate of antibody was maintained for more than 6 months.</p>