Temporal Phylogeny and Molecular Characterization of Echovirus 30 Associated With Aseptic Meningitis Outbreaks in China

BackgroundAn outbreak of aseptic meningitis occurred from June to August 2016, in Inner Mongolia Autonomous Region, China. MethodsTo determine its epidemiological characteristics, etiologic agent, and possible origin, specimens were collected for virus isolation and identification, followed by molecular epidemiological analysis. ResultsMost cases (63.1%, n = 229) were identified between June 22nd and July 17th, with children aged 6 to 12 years constituting the highest percentage (68.9%, n = 250). All viral isolates from this study belonged to genotype C of echovirus 30 (E-30), which dominated transmission in China. To date, two E-30 transmission lineages have been identified in China, of which Lineage 2 was predominant. We observed fluctuant progress of E-30 genetic diversity, with Lineage 2 contributing to increased genetic diversity after 2002, whereas Lineage 1 was significant for the genetic diversity of E-30 before 2002. ConclusionsWe identified the epidemiological and etiological causes of an aseptic meningitis outbreak in Inner Mongolia in 2016, finding that Lineage 2 played an important role in recent outbreaks. Moreover, we found that Gansu province could play an important role in E-30 spread and might be a possible origin site. Furthermore, Fujian, Shandong, Taiwan, and Zhejiang provinces also demonstrated significant involvement in E-30 evolution and persistence over time in China.