Affiliation: *Department of virology II, National Institute of Infectious Disease, Tokyo, Japan
**National Institute of health, Department of Medical Sciences, Nonthaburi, Thailand
***National reference Laboratory of poliomyelitis, Chinese Center for disease Control and Prevention, Beijing
****Center for disease control of Heilongjiang province, China
Source: Pediatrics international 2004; 46: 231-235
Background: recently, there have been large outbreaks of hand, foot and mouth disease (HFMD) mainly caused by enterovirus 71(EV71) associated with severe neurological disease in the Western Pacific Region (WAR). To monitor the realtime trend of EV 71 transmisstion throughtout the WPR, the authers conducted a molecular epidemiological analysis of EV71 infection.
Methods: Viruses were isolated from clinical sample from patients with HFMD of those with neurological complications. The EV71 isolation were identified by microneutralization assay. The VP4 and/or VP1 regions of recent EV71 isolates were sequenced and subjected to phylogenetic analysis using reference EV71 strains.
Result; The phylogenetic analysis of EV71 isolated from the WPR revealed two major genogroups, B and C, base on the nucleotide sequence alignment of the VP1 or VP4 region. These two major genogroups were further divided into subgenogroups, B1, B2, B3, and B4 and C1, C2, C3 and C4, respectively.
Conclusion: the molecular epidemiological analyses of recent and previous EV71 isolates in the WPR indicated that two major genogroups of EV71 are co-circulating in Australia, Malaysia, Singapore, Taiwan and Japan. Recent EV71 isolates in Mainland China constitute a new distinct genetic cluster, subgenogroup C4. Two major lineage of EV71 are the major causative agents of the present HFMD epidemics in the WPR and both are considered to be neurovirulent.