Phylodynamic pattern of Echovirus 30 in South America

LEMA C.; TORRES C; CISTERNA D,; GOMEZ R.; FREIRE, MC

Congreso; EUROPIC 2018; 2018

Echovirus 30 (E30) is an important causative agent of aseptic meningitis, with an epidemic pattern characterized by the temporal displacement of different lineages. Based on phylogenetic analysis of E30 VP1 sequences, 8 different lineages can be described (A to H).Recombination, a common phenomenon in Enteroviruses, may be recognized by identifying genotypic incongruence between the VP1 and 3Dpol gene regions. Despite the large number of E30 studies, information about circulating viral types in South America is still missing and the patterns of dispersion in this region are unknown. The aim of this work was to analyze the population structure of E30 lineages and the phylodynamic behavior of the current circulating variants worldwide, and to study the recombination pattern of those found in Argentina. We analyzed 79 strains isolated from meningitis cases occurred in Argentina between 1998 - 2012, and 858 VP1 E30 sequences available in GenBank. Phylogenetic trees were built by Maximum likelihood (RAXML software) and phylodynamic analyses were carried out by Bayesian coalescent method (BEAST software). Particularly, for the current circulating lineages, phylogeographical analyses were performed (BEAST software). The phylogenetic reconstruction showed a complex pattern: 8 main monophyletic groups (lineages A-H) and 8 small groups, whereas 59 sequences did not cluster with any group. The lineages A, C, D, E and F presented a wide global distribution (found in 3 or more continents), whereas the lineages B, G and H showed a more restricted distribution (found in 1 or 2 continents). In addition, lineages B, C, D, G would have been extinct (without circulation for 11 years before the most recent sample), whereas lineages A, E, F and H would be in active circulation. Phylodynamic analysis of E30 estimated that the most recent common ancestor began to diversify in 1934 with a substitution rate of 4.5 x 10-3 substitution/site/year (s/s/y). The most probable ancestor for each lineage located in USA (lineages A and E), Netherlands (lineage F) and Belarus (lineage H), showing different diversification patterns. In South America only lineages E and F were detected and described here for the first time. The analysis of E30 3CD region -the first including Latin American strains- showed different clustering than that observed in the VP1 region. Three major groups were identified. Two main groups were formed by Argentinean strains of both lineages E and F, defined in VP1, suggesting that recombination events occurred between the strains of these lineages. The third, clustering strains of lineage F (VP1) that were predominant in Argentina in 2003-2004, grouped with RF-P strains that were predominant in Europe in 2001. This is the first phylodynamic study of E30 with strains from South America. Lineages E and F were distributed worldwide in a short period of time, suggesting that they could have some evolutionary advantage over others. The analysis of both regions of the genome allow us to track the relationship between strains from different regions of the world.