Why were people living in port cities some of the earliest victims of the plague?

The plague spread around port cities, as this was along trading lines which was where usually the plague was the most. The plague spread quickly along sea trade routes, it was abundant there.

The Black Death, also known as the bubonic plague was a very deadly pandemic. Around 25 million people died in total to where they had to burn bodies in roads and dump them on islands. Infected fleas were the culprit of the Black Death and there were a lot of them on ships and trade routes.

The Silk Road spread the plague around to lots of places, as infected rats were on the ships. Since the disease spread a lot in sea and trade routes, normally people in port cities would get infected and die.

in 476 c.e. romulus, the last of the roman emperors in the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the roman empire had brought to western europe for 1000 years was no more.