[Molecular Epidemiology of Echovirus 30 in Longyan City, Fujian, China, 2011～2014].

We studied the molecular epidemiology of echovirus 30 in sporadic cases of viral encephalitis in Longyan City, Fujian, China, from 2011 to 2014.Specimens of cerebrospinal fluid from patients diagnosed with viral encephalitis or infection of the central nervous system were collected. Viruses were isolated by cell culture. Identification of the echovirus 30 serotype and genetic analyses were undertaken. Amplification of virus protein(VP)-1gene sequences was done by reverse transcription-polymerase chain reaction. A total of 168 strains of enterovirus were isolated in 608 cases from 2011 to 2014,of which 60 strains were echovirus 30.The epidemic "peak" of echovirus 30 was from June to August. The age range of patients was wide, with 65% of cases under 10 years of age. Clinical manifestations were pyrexia, headache and vomiting.Cerebrospinal fluid was clear, and the number of cells and protein was increased. The epidemic strains in Longyan City from 2011 to 2014belonged to the "h" genotype, and there were two transmission chains. Compared with the viral encephalitis strains from the outbreak in Fujian Province in 2011,they were highly homologous, but a new amino-acid variation of VP1 protein I 120 V was found in Longyan City strains from 2014.The viral encephalitis strains from the outbreak in Fujian Province in 2011 were present in Longyan City strains, and two transmission chains are still circulating,but there were new mutations in the virus strains from 2014.Continuous monitoring will aid:(i)early detection of viral variants that may accumulate;(ii)assessment of the risk of epidemics.