Identification of the First C1 Subgenotype of Enterovirus 71 in Mainland of China in a Retrospective Study

Abstract The C4 subgenotype of EV71 is identified as the most dominant subgenotype circulating in Chinese mainland since 1998, while the circulation situation of EV71 before 1998 is not well established due to insufficient experimental data. The C1 subgenotype of EV71 has not been reported in Chinese mainland by now. Based on AFP surveillance system of the mainland of China, this study performed a retrospective study of AFP cases for 1985-1999：A strain of EV-A71 C1 subgenotype was found. To our knowledge, this strain (SD92-41) is the first C1 subgenotype reported in Chinese mainland. This study proves that the C1 gene subtype appeared in Chinese mainland, but it is not clear whether it is an imported or a local epidemic strain. With sufficient information from retrospective studies, the source of the SD92-41 strain will be identified, and the prevalence of EV-A71 in Chinese mainland before 1998 will be clearer.