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|Title:||A novel multiplex suspension array for rapid subgenogrouping of enterovirus 71 (EV71) strains from the 2008 epidemic of Hand, Foot and Mouth Disease, and seroepidemiology of EV71 infection in a pediatric cohort in Singapore||Authors:||WU YAN||Keywords:||Enterovirus 71, Subgenogroups, multiplex oligonucleotids, Largest outbreak, HFMD, Seroepidemiology||Issue Date:||4-Mar-2010||Citation:||WU YAN (2010-03-04). A novel multiplex suspension array for rapid subgenogrouping of enterovirus 71 (EV71) strains from the 2008 epidemic of Hand, Foot and Mouth Disease, and seroepidemiology of EV71 infection in a pediatric cohort in Singapore. ScholarBank@NUS Repository.||Abstract:||Enterovirus 71 (EV71) belongs to the Picornaviridae family and EV71 infections can cause various clinical syndromes. This agent is the most common cause for hand, foot and mouth disease (HFMD). High fatality rate has been associated with EV71 infections during large scale HFMD outbreaks in the Asia-Pacific region and it has been found to cause neurological complication in patients. EV71 has been classified into 3 genogroups A, B and C. Genogroups B and C are subgenogrouped into B1 to B5 and C1 to C5. However, no association has been established between virulence and genogroups of EV71. So far genogrouping of EV71 only relies on direct DNA sequencing and phylogenetic analysis. In order to develop a rapid and high-throughput method for EV71 genogrouping, the xMAP® technology was applied. This technology utilizes up to 100 sets of microspheres which can be differentiated by their fluorescence. Reference strains were successfully identified and genogrouped. Viral isolates from other sources were also tested and results were consistent with sequencing results. Sensitivity tests showed that as low as 5 plaque forming units (pfu) can be detected for 9 of the subgenogroups. In the case of plasmid detection, at least 100 plasmid copies were required. Tests with clinical samples gave 100% sensitivity and specificity. The result was consistent with those obtained by RT-PCR and direct DNA sequencing. Almost 30,000 children were affected during the largest HFMD outbreak that occurred in Singapore in 2008. Clinical samples collected from National University Hospital showed that 5 different enterovirus types were co-circulating in the outbreak. CA6 and CA10 accounted for 50% of the enterovirus positive samples, while EV71 alone accounted for 30% of enterovirus positive samples. Two subgenogroups of EV71 were found to be responsible for the outbreak. The predominant subgenogroups were B5 (found in 80% of EV71 positive samples) and C2 (found in 20% of EV71 positive samples). Mutations were found in different strains of subgenogroup B5 but not in the C2 strains. Mutations in the VP1 region may explain the high incidence of cases. Sequence analysis of the 5¿UTR and 3D regions showed that current strains may possess a low virulence. HFMD incidence was high in Singapore since the year 2000; therefore seroepidemiological study may help in disease control and management. A national wide seroprevalence study was carried out in collaboration with Ministry of Health. Neutralizing antibodies were detected in 30% of investigated children. There was an increasing prevalence in older children. High prevalence in older children indicated that natural exposure to EV71 was common. Antibody titer analysis showed that infection occurred most frequently in children younger than 7.||URI:||http://scholarbank.nus.edu.sg/handle/10635/19101|
|Appears in Collections:||Master's Theses (Open)|
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