Whole genome and phylogenetic analysis of two SARS-CoV-2 strains isolated in Italy in January and February 2020: additional clues on multiple introductions and further circulation in Europe
Paola Stefanelli, Giovanni Faggioni, Alessandra Lo Presti, Stefano Fiore, Antonella Marchi, Eleonora Benedetti, Concetta Fabiani, Anna Anselmo, Andrea Ciammaruconi, Claudia Fortuna, Riccardo De Santis, Silvia Fillo, Maria Rosaria Capobianchi, Maria Rita Gismondo, Alessandra Ciervo, Giovanni Rezza, Maria Rita Castrucci, Florigio Lista, on behalf of ISS COVID-19 study group
Abstract
Whole genome sequences of SARS-CoV-2 obtained from two patients, a Chinese tourist visiting Rome and an Italian, were compared with sequences from Europe and elsewhere. In a phylogenetic tree, the Italian patient's sequence clustered with sequences from Germany while the tourist's sequence clustered with other European sequences. Some additional European sequences in the tree segregated outside the two clusters containing the patients' sequences. This suggests multiple SARS-CoV-2 introductions in Europe or virus evolution during circulation.