Using genetic data, researchers have teased out how SARS-CoV-2 has spread around the world, and the Wall Street Journal has put together maps illustrating its movements.
"We are getting this data in real-time and in volumes we've never had before," University of Basel's Emma Hodcroft, who is also a developer at Nextstrain, tells the Journal. Nextstrain, an open-source pathogen genome project, has been gathering SARS-CoV-2 genome data from different countries and, based on the mutations that arise as the virus replicates, working out how the strains are related to one another.
In its visualization, the Journal shows how the virus spread from Wuhan to other cities in China and then out of China. The first known US case in Washington State, a returning traveler, had a viral genome identical to those of samples from Wuhan. Other related cases then cropped up throughout the state, indicating community transmission, and across the US. At the same time, the visualization shows, the virus was spreading from China to Europe, and then also from Europe to the US. Strain with mutations picked up in Europe also then began to spread in the US, especially in the New York City area, as analyses from Mount Sinai and NYU researchers showed. Additionally, strains that were in Europe have also begun to return to Asia, the Journal notes. Hodcroft cautions at the Journal, though, against over interpreting the data.