Molecular typing and epidemiology of non-polio enteroviruses isolated from Yunnan Province, the People's Republic of China

This report presents an overview of human enteroviruses in Yunnan Province, the People's Republic of China. A total of 210 non-polioviruses isolated under acute flaccid paralysis (AFP) surveillance during a total study period of 5 years-1997 to 2000 and 2004-were examined. Of the 210 non-poliovirus isolates, 12 adenoviruses were serologically identified, and the remaining 198 isolates were used for molecular typing. The viral genomes of 195 non-polio enteroviruses (NPEVs) on VP1 partial region of virus capsid were translated to the corresponding amino acid sequences; these were compared with those of prototype strains. Based on molecular typing, 5 isolates were classified into 5 serotypes of the human enterovirus A species, 158 isolates, into 35 serotypes of the human enterovirus B species; and 32 isolates, into 6 serotypes of the human enterovirus C species. Viruses belonging to the human enterovirus D species were not isolated. Thus, under AFP surveillance, the human enterovirus B species accounted for 75.2% of the 210 isolates, and it was considered the predominant species. This was followed by human enterovirus C(12.2%), adenovirus (5.7%), and human enterovirus A (2.4%). Further, molecular analysis suggested that several serotypes of human enteroviruses B and C that exhibited genetic polymorphism were indigenous. Molecular typing methods may aid in understanding the epidemiology of NPEVs in Yunnan Province.