A novel reassortant H3N8 influenza virus isolated from drinking water for duck in a domestic duck farm in Poyang Lake area / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To conduct a full genome sequence analysis for genetic characterization of an H3N8 influenza virus isolated from drinking water of a domestic duck farm in Poyang Lake area in 2011.</p><p><b>METHODS</b>The virus was cultivated by specific pathogen free (SPF) chicken embryo eggs and was subtyped into hemagglutinin (HA) and neuraminidase (NA) by real-time PCR method. Eight gene segments were sequenced and phylogenetic analysis was conducted.</p><p><b>RESULTS</b>The NA gene of this virus belongs to North American lineage; other seven genes belong to Eurasian lineage. Compared with the viruses containing NA gene, the PB2 and PB1 gene came from different clades. And this indicates that the virus was a novel reassortant genotype. The HA receptor binding preference was avian-like and the cleavage site sequence showed a low pathogenic feature. There was no drug resistance mutation of M2 protein. The mutations of Asn30Asp, and Thr215Ala of the M1 protein implied the potential of pathogenicity increase in mice.</p><p><b>CONCLUSION</b>The finding of novel genotype of H3N8 virus in drinking water in this duck farm near Poyang Lake highlighted the importance of strengthening the surveillance of avian influenza in this region, which could contribute to pinpointing the influenza ecological relations among avian, swine, and human.</p>

A hepatitis A outbreak caused by contaminated well water in a primary school of Jiangxi province, China, 2009 / 中华流行病学杂志

Objective A hepatitis A outbreak in a primary school was reported by Gan County Center for Disease Control and Province (CDC) and an investigation was conducted to identify the possible source of infection and risk factors for transmission.Methods A probable case was defined as having onset of jaundice (yellow urine,sclera or skin) or a 2-fold increase in Alanine aminotransferase with 2 or more,of the followings symptoms:anorexia,disgust of oil,abdominal pain,nausea,fatigue,vomiting,in students and staff of the primary school between 1 November 2008 and 14 February 2009.A confirmed case was IgM positive for hepatitis A,added on a probable case.We searched for cases through reviewing medical records in the township hospital and village clinics and conducting symptom screening among students or teachers.We also conducted a case-control study to compare the exposure histories of 19 cases and 53 anti-HAV-IgM negative controls randomly selected from those asymptomatic students in the same grade.Results 21 cases from all the students was identified,with the attack rate as 3.5％.The epidemic curve showed the two peaks of the outbreak were 28 days apart,both indicating that they were related to the exposure of the source of origin.74％of the case-students drank the unboiled Well B water,compared to 42％ of control-students (OR=4.0,95％CI:1.1-15).The total bacterial count was 600 cfu/ml and the total coliform was 23 MPN/100 ml in one sample collected from the well water.Conclusion This hepatitis A outbreak was caused by drinking contaminated water in Well B.We recommended that all the schools should use chlorinated municipal pipe water.Public health authorities should strengthen the supervision of quality of water in schools.

Study on the application of pulsed-field gel electrophoresis regarding infection sources identification during an outbreak of Vibrio cholerae in Jiangxi Province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the correlation between Vibrio cholerae strains isolated from natural enviroment and fishery products and the source of infection during V. cholerae outbreaks.</p><p><b>METHODS</b>Cholera toxin gene was detected by polymerase chain reaction (PCR) amplification. Pulsed-field gel electrophoresis (PFGE) was used to subtype the isolates. Results of PFGE were analyzed and clustered by BioNumerics software (Version 4.0).</p><p><b>RESULTS</b>During the outbreaks, a total number of thirty O139 V. cholerae related serogroups were collected from patients, carriers, sewage and fishery products were identified and proved to be toxigenic. They could be clustered into four PFGE patterns when digested by Not I. These two V. cholerae outbreaks were caused by the same source of infection because of the following reasons: (1) PFGE patterns of the predominant strains isolated from two outbreaks were identical; (2) they were identical to the PFGE patterns of the strains isolated from the green turtle and rana catesbiana which were bought from the same wholesale store.</p><p><b>CONCLUSION</b>Green turtle and rana catesbiana that were contaminated by toxigenic O139 V. cholerae strains seemed to be the source of infection causing the O139 V. cholerae outbreaks in Jiangxi province. Rapid laboratory surveillance and epidemiologic investigation were important in identifying the source of infection during the outbreaks of V. cholera.</p>