Merkel-cell polyomavirus and human polyomavirus 6 in Argentina, Uruguay, and Spain: Deep characterization of the South American types

TORRES, C; BARRIOS, ME; CAMMARATA, RV; VICTORIA, M; FERNANDEZ-CASSI, X; BOFILL-MAS, S; COLINA, R; BLANCO FERNÁNDEZ, MD; MBAYED, VA

Workshop; 22nd International Bioinformatics Workshop on Virus Evolution and Molecular Epidemiology (VEME); 2017

New human polyomaviruses have been discovered in the last years, including the Merkel-cell (MCPyV) and the human polyomavirus 6 (HPyV6). Although their infection is usually asymptomatic, in immunocompromised hosts they can cause life-threatening pathologies. In particular, MCPyV has been associated with Merkel cell carcinoma, an aggressive skin cancer arising in the elderly and in chronically immunosuppressed individuals. Despite being prevalent viruses, epidemiological data from South America are scarce, as too are the viral types circulating and their origin. The aims of this work were to characterize MCPyV and HPyV6 from environmental samples with different geographical origins and to analyze the phylogenetic and phylogeographic profiles to study their spatio-temporal dispersion patterns, particularly for MCPyV. Partial and complete genome sequences were obtained from sewage samples from Argentina, Uruguay, and Spain. Phylogenetic analysis showed that MCPyV sequences distributed according to their geographic origin in Europe/North America, Africa, Asia, South America, and Oceania groups, suggesting that viral diversification might have followed human migrations across the globe. In fact, the analysis of the viruses reported here emphasized this behavior, given that they reflected the origin of the current population in each country. The South American group presented a high level of clustering, showing subgroups exclusively formed by sequences from southern South America, possibly associated with local diversification events related to early migratory movements in the region. Regarding HPyV6, sequences from South America grouped with high support and were separated from all other sequences available, from USA, France, Australia, and China. The analysis of viruses from the environment allowed us to characterize prevalent infections in different geographic regions, revealing that viruses circulating in each population reflected its origin and that there are specific lineages associated with South America.