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.

  1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Malaysia C1, C2, B3, B4 C1 C1 B4, C1   C1 B5, C1   B5, C1 B5        
Singapore B3, B4 B3, C1 B3 B4 B4 B4, C1       B5   B5    
Taiwan   B4, C2, C4 B4 B4 B4 B4, C4 B4, B5 C4 C4 C5 B5, C5 B5 B5 C4
Japan C2, B3, B4 C2 C2 C2, B4 C2 B4, C2, C4 C4, B5 C4   C4 C4      
China   C4   C4 C4 C4 C4 C4     C4 A, C4 C4  
Vietnam                 C1, C4, C5        
Australia   C2 B3, C2 B4, C1 B4, C1 C1 C1 C4            
Korea       C3                 C4  
The Netherlands C1, C2   C2 C2 C1 C1, C2   C1, C2 C1, C2   C1, C2 C2    
United Kingdom   C1 C1, C2 C1 C1 C1   C1   C1, C2        
Norway           C1 C1              
Austria         C1 C1 C1 C4            

Bold indicates predominant genotype.
doi: 10.1371/journal.0001737.t006

Table 1. Distribution of EV71 genotypes throughout the world from 1997 to 2010

EV71 Strain Source