The Sars-Cov-2 virus began to circulate in a hidden way already in late January in Europe and in Italy , before the first cases of disease emerged in Codogno. The starting point of what is a vast all-European epidemic were the German cases, detected between 24 and 27 January, to which Italian cases are also connected. Gianguglielmo Zehender of the Statale di Milano explains, whose study has now been published in the Journal of medical virology, after the first online publication on the Medrxiv website.
The work, coordinated by Massimo Galli, analyzed the virus genome of 3 of the first 16 cases of Covid-19 in the province of Lodi on 20 and 21 February. "The epidemiological timing - observes Zehender - shows how the Bavarian cases preceded the appearance of the first Italian cases by at least 1 month and suggests that the one that emerged with the Lombard outbreak outlines an epidemic of European extension". The sequences have been published in the Gisaid database, available to the international scientific community.
The analysis of the 3 genomes of the Codogno patients virus, compared with those available in the Gisaid database, allowed to understand that the strain is closely related to the one isolated for the first time by a patient who fell ill with Covid-19 between 24 and on January 27, 2020 in Bavaria, after a meeting a few days earlier with a Chinese manager from Shanghai, who had recognized the symptoms of Covid-19 only on the return home.
"The virus isolated in Italy is similar to that isolated in Germany, with which it has a clear relationship. The introduction in Italy started from there, around January 25th, as confirmed by both epidemiological and molecular data", explains Massimo Galli, study coordinator. From the first German cases, therefore, the Lombard outbreak arose, and then the other European cases. The same viral strain has in fact been isolated not only in Italy, but in other European countries, such as Finland, and in Latin America (Brazil and Mexico). However, the study could not conclusively demonstrate the direct link of the strain present in Italy with the outbreak in Germany, as multiple exports of the same variant directly from China to Germany and Italy were theoretically possible (although very unlikely). .
