for switzerland, covid-19 does not appear to be a function of density or culture per se, as the article and map linked shows:
as of the date of the article (march 19), the most cases seem clustered at selected national border cantons— basel-stadt, geneva/vaud, and ticino. zürich, for example, seems relatively untouched by comparison (and it has an extensive tram system).
As I read it Zurich has 1476 cases. The black number 9 centered on
Zurich on the map is just deaths.
L