Laboratory diagnosis and genetic analysis of a family clustering outbreak of aseptic meningitis due to echovirus 30.

Echovirus 30 (E30) is a major pathogen associated with aseptic meningitis. In the summer of 2014, a family clustering aseptic meningitis outbreak occurred in urban-rural fringe of Ningbo city in Zhejiang Province in China. To identify the etiologic agent, specimens were tested by cell culture and reverse transcriptase-polymerase chain reaction. Pathogenic examination confirmed that the outbreak is caused by E30. The first case is a 6-year-old child, who studied in kindergarten in local, suffered from headache and fever. Same symptoms appeared in his parents, aunts, and other six relatives continuously. Meanwhile, vomiting occurred in majority of the patients and diarrhea in parts of them. White blood cells in cerebrospinal fluid (CSF) exceeded normal range in all patients. Protein levels in CSF were above normal range in half of the patients. Glucose levels in CSF were within normal range in all patients. We isolated six strains E30 in the stool specimens of patients, and carried out sequencing analysis to VP1 region. Sequencing results showed that 100% sequence identity was seen in both nucleotide and amino acid levels. Phylogenetic analysis discovered that isolate in this study was grouped into sublineage D2 together with sequences isolated from other areas of China in the 2000s and 2010s. Our study is the first family clustering outbreak of aseptic meningitis caused by E30 in Zhejiang Province in China. It is essential to establish an enterovirus molecular surveillance system in China to prevent mass outbreaks in Zhejiang.