Possible recombination and gene adaptation exchanges among clinical echovirus strains: crossing the temporal and topological barriers.

Six echovirus strains belonging to serotypes echovirus 6, 13, and 30 were investigated in the present work by sequencing of the whole 2C gene and about 560 nt of the 5' part of 3-dimensional genomic region. Four of the 6 echovirus strains were epidemics, whereas 2 were from sporadic cases. The whole procedure was carried out by using nucleotide distance matrices and phylogeny software. The sequences obtained strengthen the observation that recent echovirus isolates differ significantly from prototype strains in the downstream regions of the genome and provides further evidence that nonstructural enterovirus genes are ubiquitous and may combine freely adapting genomic sequences that are not restricted from the place of isolates' origin. For diagnostic purposes, particular emphasis is given on the utility of sequencing downstream genes and comparison of them with corresponding genomic regions from enteroviral strains that circulated all over the world.