Isolation and identification of Japanese encephalitis virus in Liaoning Province / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To study arboviruses carried by mosquitoes in Liaoning Province in 2002.</p><p><b>METHODS</b>Totally 4927 mosquitoes were collected from Liaoning Province in July 2002. Virus strains were isolated by inoculating BHK-21, C6/36 and Vero cells. The newly isolated strains were identified by serological (ELISA and IFA) and molecular methods (Real-Time PCR and RT-PCR).</p><p><b>RESULTS</b>Two strains were isolated from mosquitoes causing cytopathogenic effect (CPE) on cells and were fatal to suckling mice. Serological tests showed that both were positive for the antibody to JEV. The PrM and E gene were cloned and sequenced. The phylogenetic analysis showed that the new isolates belonged to genotype I, JEV. Sequence analysis showed that the homology of nucleotide sequences and amino acid (AA) sequences between the two strains was 100%. Compared with the nucleotide sequences between the two strains and the standard JEV vaccine strain SA14-14-2, the difference was up to 4.11%, and the difference of AA was 0.6%.</p><p><b>CONCLUSION</b>Two strains of JEV were isolated and identified in Liaoning province, both belonged to genotype I JEV.</p>

Distribution and timing of antibody to SARS-CoV in SARS cases of transmission chain or non-transmission chain / 中华实验和临床病毒学杂志

<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>