Genomic Snapshot of SARS-CoV-2 in Migrants Entering Through Mediterranean Sea Routes.

Nicole Grandi,Enzo Tramontano,Claudia Piu,Salvatore Rubino,Caterina Serra,Roberto Cusano,Bianca Paglietti,Vincenzo Lai,David J Kelvin,Gabriele Ibba,Flavia Angioj

doi:10.3389/fpubh.2022.846115

Abstract

In December 2019, a novel coronavirus emerged in Wuhan, China, rapidly spreading into a global pandemic. Italy was the first European country to experience SARS-CoV-2 epidemic, and one of the most severely affected during the first wave of diffusion. In contrast to the general restriction of people movements in Europe, the number of migrants arriving at Italian borders via the Mediterranean Sea route in the summer of 2020 had increased dramatically, representing a possible, uncontrolled source for the introduction of novel SARS-CoV-2 variants. Importantly, most of the migrants came from African countries showing limited SARS-CoV-2 epidemiological surveillance. In this study, we characterized the SARS-CoV-2 genome isolated from an asymptomatic migrant arrived in Sardinia via the Mediterranean route in September 2020, in comparison with SARS-CoV-2 isolates arrived in Sicily through the Libyan migration route; with SARS-CoV-2 isolates circulating in Sardinia during 2020; and with viral genomes reported in African countries during the same summer. Results showed that our sequence is not phylogenetically related to isolates from migrants arriving in Sicily, nor to isolates circulating in Sardinia territory, having greater similarity to SARS-CoV-2 genomes reported in countries known for being sites of migrant embarkation to Italy. This is in line with the hypothesis that most SARS-CoV-2 infections among migrants have been acquired prior to embarking to Italy, possibly during the travel to or the stay in crowded Libyan immigrant camps. Overall, these observations underline the importance of dedicated SARS-CoV-2 surveillance of migrants arriving in Italy and in Europe through the Mediterranean routes.

Highlights

At the end of December 2019, an outbreak of a novel coronavirus, SARS-CoV-2 originated in Wuhan, China, and rapidly expanded into a global pandemic causing COVID-19 disease [1]
The number of migrants/refugees landing on Italian borders via the Mediterranean route in September and October increased by 345% in 2020 compared to the same period in 2019 [4] underscoring the need for rapid surveillance of migrant infections
8 passengers were immediately transferred to a hospital by the Italian authorities for medical reasons, while the remaining 125 migrants were screened for SARS-CoV-2 infection

Summary

Introduction

At the end of December 2019, an outbreak of a novel coronavirus, SARS-CoV-2 originated in Wuhan, China, and rapidly expanded into a global pandemic causing COVID-19 disease [1]. The number of migrants/refugees landing on Italian borders via the Mediterranean route in September and October increased by 345% in 2020 compared to the same period in 2019 [4] underscoring the need for rapid surveillance of migrant infections. Few studies have genetically characterized SARS-CoV-2 among migrants and refugees, as they are considered a vulnerable population, which underscores the need for genomic surveillance that could lead to the introduction of novel SARS-CoV-2 variants [7] In this pilot study, phylogenetic and virological analyses were performed to investigate the genomic origin of the SARS-CoV-2 isolate obtained from an asymptomatic migrant who tested positive by RT-PCR at the time of arrival in Sardinia, Italy, via the Mediterranean route. Comparison with other SARSCoV-2 isolates recently identified in immigrants from the Libyan migration route [8] allowed us to assess similarities with other viral genomes from comparable contexts

Methods

Results

Conclusion