| Summary: | 碩士 === 國立陽明大學 === 微生物及免疫學研究所 === 100 === Enterovirus 71 (EV71) is a common causative agents of hand, foot, and mouth disease and sometimes causes severe neurologic complications, mainly in children. Outbreaks of EV71 infection have been reported worldwide in countries in Europe, America, and the West Pacific region. According to VP1 sequences, EV71 can be phylogenetically diverged into three genotypes: A, B and C. Genotype B and C can be further divided into five subgenotypes – genotypes B1-B5 and C1-C5. Genotype B is predominant in Malysia and Singapore, whereas genotype C is predominant in China. In 1998, outbreak of EV71 in Taiwan which causes 78 children deaths belongs to subgenotype C2.Whereas subgenotype of EV71outbreak in 2000, 2004 and 2008 is belong to B4, C4 and B5. The substitution of EV71differant subgenotypes is interesting and in 2010 to 2012, EV71 subgenotypes recycle to C4, B5 and C4.
We cultured virus from Taichung Veterans General Hospital from 2002 to 2012, confirmed by IFA with anti-EV71 monoclonal antibody. After extraction of Viral RNA, we selected the patients (174/ 218) followed by RT-PCR amplification of VP1 region, sequencing and phylogenetic analysis. The subgenotypes of EV71 we identified are similar to EV71 circulating in Taiwan from 2002 to 2012, yet in 2011 we found that EV71 subgenotypes B5 (15/21) was predominant, that Taiwan were mainly circulating C4 strain. And we also noticed that before epidemic years of EV71 a minor strain of virus already exist and the period of genotype substitution became faster. After phylogenetic tree analysis we found that some of EV71 outbreaks in 2010 are most related to EV71 China strains in 2010 and the others are related to Taiwan local isolate in 2004 and 2005. And also 2011, 2012 strains are related China strain.
Base on phylogenetic analysis we identified EV71 subgenotypes and those viruses could be import from nearby area or maintain in local area, and it could contribute for public policy and vaccine development.
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