Pathological and molecular characteristics of a viral meningitis outbreak among pupils in Jinhua city of Zhejiang province, 2014

Objective To identify and trace the pathogen of a suspected viral meningitis outbreak in a primary school in Jinhua city of Zhejiang province in 2014.Methods Epidemiological investigation was conducted and 3 specimens of cerebrospinal fluids (CSF) and 3 of throat swab were sampled from suspected patients for isolation and detection of human enterovirus (HEV) nucleic acid.Then VP1 genes of the isolated virus were sequenced for the construction of phylogenetic tree and homologous analysis.Results Totally 7 cases aged 7 to 8 years were identified among 328 pupils in the school,with a morbidity of 2.13%.All the cases had symptoms of headache,fever,and vomiting.Six specimens from 5 patients were positive for HEV nucleotide and 3 strains of echovirus 30 (E30) were isolated from CSF specimens.The homology of nucleotide sequences of the VP1 gene was 81.8% and that of amino acid sequences ranged from 91.8% to 92.1% between the 3 isolated strains and the prototype strain Bastianni of E30,respectively.The phylogenetic tree of VP1 gene showed that the E30 strains isolated belong to the E30 G subtype and are of close homology to CHN/ZJ/RA-72/13 strain isolated in Zhejiang province in 2013.Conclusion The viral meningitis outbreak among pupils in Jinhua city of Zhejiang province in 2014 was caused by echovirus 30 G genotype.