If the plague was an infectious disease spread by bacteria from the fleas of rats, then there would be no way for Jews to avoid it as they can’t prevent fleas entering their homes in the medieval times.

In reality, it was because the Jew poisoned the wells of the Christians which is why only White people died while the Jew went untouched.

If the plague was a result of bacteria, then Jews who are known to be filthy because of their aversion to hygiene would actually get far sicker than Aryans who value cleanliness.