title: Reemergence of enterovirus 71 epidemic in northern Taiwan, 2012.
abstract: BACKGROUND
  Enterovirus 71 (EV71) belongs to picornavirus family and could be classified phylogenetically into three major genogroups (A, B and C) including 11 genotypes (A, B1-B5 and C1-C5). Since 1997, EV71 has caused large-scale of epidemics with neurological complications in Asian children. In Taiwan, nationwide EV71 epidemics with different predominant genotypes have occurred cyclically since 1998. A nationwide EV71 epidemic occurred again in 2012. We conducted genetic and antigenic characterizations of the 2012 epidemic.
  
  
  METHODS
  Chang Gung Memorial Hospital (CGMH) is a medical center in northern Taiwan. In CGMH, specimens were collected from pediatric inpatients with suspected enterovirus infections for virus isolation. Enterovirus isolates were serotyped and genotyped and sera from EV71 inpatients were collected for measuring neutralizing antibody titers.
  
  
  RESULTS
  There were 10, 16 and 99 EV71 inpatients identified in 2010, 2011 and 2012, respectively. There were 82 EV71 isolates genotyped, which identified 17 genotype C4a viruses and 65 genotype B5 viruses. The genotype B5 viruses were not detected until November 2011 and caused epidemics in 2012. Interestingly, the B5-2011 viruses were genetically distinguishable from the B5 viruses causing the 2008 epidemic and are likely introduced from China or Southeastern Asia. Based on antigenic analysis, minor antigenic variations were detected among the B5-2008, B5-2011, C4a-2008 and C4a-2012 viruses but these viruses antigenically differed from genotype A.
  
  
  CONCLUSIONS
  Genotype B5 and C4a viruses antigenically differ from genotype A viruses which have disappeared globally for 30 years but have been detected in China since 2008. Enterovirus surveillance should monitor genetic and antigenic variations of EV71.
authors.affiliation: National Institute of Infectious Disease and Vaccinology, National Health Research Institutes (NHRI), Zhunan Town, Miaoli County, Taiwan.
authors.forename: Shu-Ting
authors.initials: ST
authors.lastname: Luo
authors.affiliation: National Institute of Infectious Disease and Vaccinology, National Health Research Institutes (NHRI), Zhunan Town, Miaoli County, Taiwan.
authors.forename: Pai-Shan
authors.initials: PS
authors.lastname: Chiang
authors.affiliation: National Institute of Infectious Disease and Vaccinology, National Health Research Institutes (NHRI), Zhunan Town, Miaoli County, Taiwan.
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Chung
authors.affiliation: National Institute of Infectious Disease and Vaccinology, National Health Research Institutes (NHRI), Zhunan Town, Miaoli County, Taiwan.
authors.forename: Min-Yuan
authors.initials: MY
authors.lastname: Chia
authors.affiliation: Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Gueishan Town, Taoyuan County, Taiwan; Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Gueishan Town, Taoyuan county, Taiwan.
authors.forename: Kuo-Chien
authors.initials: KC
authors.lastname: Tsao
authors.affiliation: Department of Pediatrics, Chiayi Chang Gung Memorial Hospital, Puzi City, Chiayi County, Taiwan.
authors.forename: Ying-Hsiang
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Linkou Chang Gung Memorial Hospital, Gueishan Town, Taoyuan County, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Gueishan Town, Taoyuan County, Taiwan.
authors.forename: Tzou-Yien
authors.initials: TY
authors.lastname: Lin
authors.affiliation: National Institute of Infectious Disease and Vaccinology, National Health Research Institutes (NHRI), Zhunan Town, Miaoli County, Taiwan.
authors.forename: Min-Shi
authors.initials: MS
authors.lastname: Lee
mesh_terms: D057134:Antibodies, Neutralizing / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004770:Enterovirus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D004769:Enterovirus Infections / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D010802:Phylogeny; D013624:Taiwan / Q000453:epidemiology
chemical_list: D057134:Antibodies, Neutralizing; D000956:Antigens, Viral