ABSTRACT
OBJECTIVE: To study the epidemical characteristics of influenza/novel influenza A (H1N1) in Shanxi province from 2009 to 2010, and to provide scientific foundations for predicting and controlling the pandemic outbreak of influenza/novel influenza A (H1N1) effectively. METHODS: All samples were collected from cases that resemble influenza cases in sentinel hospital and influenza outbreak. The influenza were detected by PCR and isolated by MDCK cell culture method. Finally, Shanxi province surveillance data from May, 2009 to April, 2010 of influenza like illness (ILI) cases and pathogen detections were analyzed. RESULTS: In Shanxi province, influenza viruses kept activation in whole year. The predominant pandemic strain in 2009 was novel influenza A (H1N1) virus. The strong peak was around November, 2009 [positive rate: 58.1%, novel influenza A ( H1N1) of the total: 88.1%]. As well, the people infected influenza caused by novel influenza A (H1N1) were mainly under 59-year-old, and the higher positive rates were concentrated in the people from 5-year-old to 24-year-old. In 2010, influenza B (Victoria) viruses were mainly detected from clinical specimens and became the dominant strain. CONCLUSION: Surveillance of Influenza liue illnes, (ILI) and etiology, which can promptly reflect the influenza epidemic situation, play a significant role for understanding epidemic rule of influenza/novel influenza A (H1N1).
Subject(s)
Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/virology , Adolescent , Adult , Age Factors , Aged , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Influenza, Human/etiology , Middle Aged , Time FactorsABSTRACT
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: H1N1 epidemic influenza did occur among children in winter and spring of 2005--2006 in Taiyuan city.
Subject(s)
Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza, Human/epidemiology , Population Surveillance , Adolescent , Animals , Antibodies, Viral/blood , Cell Line , Child , Child, Preschool , China/epidemiology , Dogs , Hemagglutination Inhibition Tests , Humans , Infant , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza B virus/isolation & purificationABSTRACT
Among 176 patients who had had severe acute respiratory syndrome (SARS), SARS-specific antibodies were maintained for an average of 2 years, and significant reduction of immunoglobulin G-positive percentage and titers occurred in the third year. Thus, SARS patients might be susceptible to reinfection >or=3 years after initial exposure.
Subject(s)
Antibodies, Viral/immunology , Antibody Formation/immunology , Immunoglobulin G/blood , Severe Acute Respiratory Syndrome/immunology , Severe acute respiratory syndrome-related coronavirus/immunology , Antibodies, Viral/blood , China , Humans , Longitudinal StudiesABSTRACT
BACKGROUND: 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. METHODS: The IgG and IgM antibodies to SARS-CoV were tested by indirect ELISA in serum samples from 301 clinically diagnosed SARS cases. RESULTS: 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. CONCLUSION: 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.