“Plague” in this sense is not a metaphor, but the 20th century introduction of infected fleas by humans which started in San Francisco: https://news.ycombinato

“Plague” in this sense is not a metaphor, but the 20th century introduction of infected fleas by humans which started in San Francisco: https://news.ycombinator.com/item?id=24388115 https://news.ycombinator.com/item?id=24388115