I think a lot was done to sanitize medieval Europe as well. Serfs come from slavery, the name servus in Latin, is slave, the modern word slave, comes from enslaving Slavic people, using them as galley, and plantation slaves. In turn the word for Gulag, comes from the Belarus-Russian-Ukrainian word Katorga, a transliteration of a Greek and Turkish word for galley, as in the ship. The Genonese slave-raiding colonies, Garazia, was in constant warfare with the Mongols from the 13th to 15th centuries. In one siege the Mongols used artillery to launch Black Plague infected corpses over the walls of Kaffa, likely a vector of how it entered Europe.