Japanese encephalitis virus with genotype I is predominant in Sichuan Province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To understand molecular characteristics of Japanese encephalitis virus (JEV) isolated from the major Japanese encephalitis epidemic areas in Sichuan Province, and to provide the foundation for JEV prevention.</p><p><b>METHODS</b>13 JEV strains were isolated from mosquitoes in Sichuan during 2007-2010, E genes and preM genes were sequenced and phylogenetic analyses were performed using MEGA5 molecular software.</p><p><b>RESULTS</b>Phylogenetic analysis indicated that all 13 JEV strains from Sichuan belonged to genotype I, homologies at nucleotide level and deduced amino acid level in PreM gene were 97%-100% and 98.7%-100%, and 97.8%-99.9% and 99.6%-100% in E gene, respectively. Homologies at nucleotide level and deduced amino acid level in PreM gene between 13 JEV strains and JEV isolated in 2004 in Sichuan were 96.2%-99.1% and 97.5%-98.7%, and were 97.7%-99.6% and 98. 6%-100% in E gene, respectively. By comparison with vaacine strains P3 and SA14-14-2, homologies at nucleotide level and deduced amino acid level were 84.1%-85.8% and 93.7%-96.2% in PreM gene, and were 87.6%-88.3% and 97%-97.8% in E gene, respectively. The neurovirulence-related 8 amino acid sites encode by E gene remained unchanged in 13 JEV strains.</p><p><b>CONCLUSION</b>JEV with genotype I predominated in Sichuan, nucleotide sequences and deduced amino acid sequences in PreM gene and E gene were highly conserved, key neurovirulence-rerlated sites remained unchanged. It suggested currently used vaccine is still capable of preventing JEV infection.</p>

Anlysis on features of dead cases with human Streptococcus suis infections / 中华流行病学杂志

<p><b>OBJECTIVE</b>To describe the clinical and epidemiological features of dead cases with human Streptococcus suis infections, and to find the target population for preventing death and the related indicators.</p><p><b>METHODS</b>Epidemiological investigation on human Streptococcus suis infections was implemented used unified questionnaires. Analysis on dead cases and survival cases (as contrast) was done.</p><p><b>RESULTS</b>The population with highest fatality rate was in 40-49 age group. 97.37% of dead cases had toxic shock syndrome. The mean interval from onset to admission was 0.76 days, and the mean course was 2.11 days. The progression among dead cases was faster than that among survival cases. Chief clinical manifestations of dead cases that are more frequent than survival cases are purpura (73.68%), diarrhea (50.0%), dyspnea (21.05%), conjunctival congestion (34.21%), etc. Renal impairment and liver involvement in dead cases were more significant than that in survival cases. No significant difference between mean incubation period, exposure rates of main risk factors in dead cases and in survival cases was found.</p><p><b>CONCLUSION</b>Preventing toxic shock syndrome might reduce the fatality rate. The target population for preventing death is aged > or = 40. Liver function and renal function testing might be indicators for monitoring the progression of human Streptococcus suis infections.</p>

Matched case-control study for risk factors of human Streptococcus suis infection in Sichuan Province, China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the potential risk factors of human infecting with Streptococcus suis.</p><p><b>METHODS</b>1: M matched case-control study was conducted. 29 human cases of Streptococcus suis infection in the early phase were included in the case group, Patients' family members, neighbors and peoples who had worked together with patients to handle deceased or sick pigs in the last week were recruited as matched controls. There were 147 controls in total. Both cases and controls received questionnaire investigation including the ways to contact sick/dead pigs. Conditional logistic regression was employed to analyze matching data.</p><p><b>RESULTS</b>According to the results of multivariate analysis, slaughtering (OR = 11.978, 95% CI: 3.355-42.756), carcasses cutting and processing (OR = 3.008, 95% CI: 1.022-8.849) sick/dead pigs were associated with cases related to human Streptococcus suis infection. The attributable risk proportion were 91.65% and 66.76% respectively. The other types of exposures to sick/ dead pigs, including feeding, selling, burying and eating, were not associated with the human Streptococcus suis infection in our study population.</p><p><b>CONCLUSION</b>Slaughtering, carcasses cutting and processing sick/dead pigs were important risky behavior for humans to be infected by Streptococcus suis.</p>