In a story from MIT technology review we get clues to how SARS-CoV-2 are spreading throughout the world, and how transmission chains are not always what they seem to be. By tracking random mutations in the virus’ DNA sequence, as documented in the open source effort Nextstrain, it is possible for scientists to follow the evolution of the pandemic in in near real time.

For example, analysis of the virus genome shows that since february 1st, one forth of all new cases can be traced back to a business man in Munich, Germany, patient 1, who contracted the virus from a chineese business partner, visiting from Shanghai. The businessman, employed by Webasto, fell ill and within four days, four more employees were infected and the company headquarters were closed down. But this was not enough, as we shall see.

Six weeks later, a 38 year old top athlete in Italy, had contracted a nasty pneumonia. He had no history of illness, and there were little suspicion that he could have concieved the corona virus. However, on a hunch, a GP decided to test him and found that we was indeed infected and was diagnosed with COVID-19. Furthermore, the virus in the italian athlete is a genetical decendant of the virus infecting the Munich business man. Thus, the virus had silently spread in europe for six weeks before finally being detected.

Now the Munich branch of the virus is spreding throughout the world, showing with terrifying detail what happen if the SARS-CoV-2 is allowed to operate undetected. A great deal of the cases currently in europe can be traced back to patient 1 in Munich, around january 20th.