Sequencing and Molecular Characterization of the Genome of Echovirus 30 Isolated from a Korean Aseptic Meningitis Patient

Echovirus 30 is one of the distinct serotypes of enteroviruses and commonly isolated agent causing sporadic to large outbreaks with aseptic meningitis in many regions over the world. Recently, an outbreak of echovirus 30 associated with aseptic meningitis occurred in Korea in 2008. In order to analyze echovirus 30 in Korea, the virus was isolated from cerebrospinal fluid samples of a male patient with aseptic meningitis and its genome sequence was determined. The sequence of Korean echovirus 30 isolate was compared with those of reference strains (Bastianni, FDJS03-84, zhejiang-17-03, 14916net87). At the nucleotide level, the P1 region (84.8~89.0%) had the highest identity value; at the amino acid level, the P3 region (97.0~98.5%) showed the highest value. When the cleavage sites were compared, most sites were identical except those between VP1 and 2A; the Bastianni stain had TT/GA, whereas the other four strains contained NT/GA. The China strains (FDJS03-84 and zhejiang-17-03) were grouped together and the other strains were distinct from each branch in the phylogenetic tree based on the complete genome sequences.

Genetic Diversity of Echovirus 6 Strains Circulating in Korea

Echovirus 6 (ECV6) is the prevalent serotype detected in aseptic meningitis cases in Korea. To analyze the genetic variation of ECV6 isolates recently circulating in Korea, we determined the partial sequence of the VP1 capsid gene from 22 Korean ECV6 isolates and performed pairwise analysis against 42 reference strains from the GenBank database using MegAlign. The 22 Korean ECV6 isolates formed 3 distinct genetic clusters: Kor-lineage I, II, and III. The Korean ECV6 strains showed significant genetic diversity with 14.8~22.8% nucleotide divergence among the 3 different lineages. These ECV6 Kor-lineages were demonstrated to belong to different genetic clusters using VP1 sequence-based phylogenetic analysis, implying that the recently circulating Korean ECV6 strains have potential antigenic variation.