Objective: To investigate pathogens and molecular-epidemiology characteristics of viral meningoencephalitis in the monitoring sites of Zhejiang province, 2013.
Methods: Cerebrospinal fluid and/or stool specimens were collected from suspected patients admitted to the monitoring hospitals in southern and northern Zhejiang province. Such specimen were subject to real-time qPCR for the detection of Human enterovirus (HEV), Japanese encephalitis virus (JEV), Mumps virus (MuV), Herpes simplex virus (HSV) and Cytomegalovirus (CMV). HEVs were isolated using the RD and Hep-2 cell lines, while VP1 genes from all HEV-positive isolates or RNA-positive specimen were amplified, sequenced, for homology and evolution analysis.
Results: 92 (38.5%) of the 239 samples collected from 229 patients were detected as virus nucleic acid positive, including 87 HEV positive samples, 1 MuV positive, 2 HSV positive, and 2 CMV positive; of the 87 HEV positive samples, 38 were further determined to be Coxsackievirus (CV) and 49 as Echovirus (E). 56 HEV strains were isolated from 239 (23.4%) samples. From the 31 cerebral fluid specimen of nucleic acid positive yet virus isolation negative, the most specimen were identified with E9 (9 specimen), followed by CVA9 (8 specimen); the viral serotype of Zhejiang province HEV were CVA9, CVB4, CVB5, E6, E7, E9, E11, E14, E16, E25 and E30, respectively. Predominant epidemic strains identified at southern and northern Zhejiang province were CVB5 and E6 respectively. The phylogenetic analysis of VP1 gene showed that all the HEV isolates in Zhejiang province were HEV-B.
Conclusion: The HEV-B was the main pathogen for viral meningoencephalitis in Zhejiang province in 2013, including 11 serotypes, while E7 was the first time to be isolated in Zhejiang province. The predominant isolates were CVB5 and E6 in southern and northern Zhejiang province respectively. The positive rate of viral nucleic acid detection was significantly higher than that of viral isolation. Regular EV isolation method was exposed to the risk of missing-detection of E9 and CVA9.