Genetic Variations of Enterovirus 71 (EV71)

The molecular genotyping and epidemiological surveillance of enterovirus 71 / EV71 is conducted by detecting viral VP1. Up to now, three genotypes of enterovirus 71 / EV71 are identified, including genotype A, B and C. Moreover, genotype B can be classified into 5 sub-genotypes, named from B1 to B5; and genotype C also contains 5 sub-genotypes, which are C1 to C5. The outbreak of enterovirus 71 / EV71 appears frequently in the Asia-Pacific region since 1997, and countries such as Malaysia, Singapore, Japan, mainland China, and Taiwan are seriously affected, where sub-genotypes B5 and C4 are found.

In mainland China, sub-genotype C4 is predominant in enterovirus 71 / EV71 infection, and it reached Guangdong province in 1998. Enterovirus 71 / EV71 epidemics is initially restricted to the south of China, nevertheless, it has been expanded to the other areas since 2004. Epidemics of HFMD associated with EV71-associated neurological syndrome have been reported in Anhui, Shandong, Shanghai, and Beijing; meanwhile, there have been sporadic HFMD cases in other provinces. In 2008, 488,955 HFMD cases have been confirmed nationwide, of which 126 are fatal cases.