They forgot to wear their plague masks?
There was a study about 10 or so years ago analyzing the speed of plague, documented by village church records, across England in 1348 (generally accepted as the first year of Black Death).
The conclusion of the study was that rats can’t move that fast so maybe Yersenia Pestis (the bacteria) was not responsible for plague. Suggestions of multiple years of famine arose as having weakened the populace and making people susceptible to random virus events.
When this happened, mass graves in England were opened and DNA samples were taken from the bodies. All were found to have Y. Pestis DNA residual, added to all of the documented stories of the time about symptoms that match up well.
So this article today is attempting to reconcile the two items of research. Yes, Y. Pestis, but maybe not via rats, they want to say.
The rat concept arose because of how they were everywhere and how port cities got hit first.
City to city transport could be other animals with fleas (horses?), but to get everywhere inside a city so fast, rats still seem like a good explanation.
Note there was a plague outbreak in Chinatown of San Francisco in 1900. Smaller population then, of course. 100+ cases and all but 2 died.
The governor of California tried to deny anything of the sort was happening and shut off mitigation rules like quarantine and other measures taken. Ships from Asia were flagged as possible plague carriers. This was bad for business and his reasons for shutting down prevention were economic damage to the state. There was an election in 1902 and he lost. The winner then spent big money on mitigation.
Then in 1906 the great San Fran earthquake burned up most of the city. In 1907 plague hit the city again during reconstruction, though outside Chinatown and in suburbs, including across the bay in Oakland.
Another 150+ infected, 70+ deaths — a lower rate. All were European this time rather than Asian. There had been articles in 1900 saying California was plague immune because Asians (many plague outbreaks in Asia 1895+) ate a rice rich diet and Euro descent Americans ate meat and this was claimed decisive. It is generally likely that reservoirs in the US now in Colorado Utah Arizona and New Mexico rodents were established in squirrels that travelled from California in the early 1900s.
It’s because their feet were a lot smaller than ours so when they stayed 6 feet apart, they were really only about 3-4 feet apart...