The Cholera Epidemic actually occurred in Manila in the year 1820 during the Spanish Colonization in the Philippines. The deadly cholera epidemic led to a massacre of many foreigners, mostly Europeans and Chinese nationals, just because of a rumor that these foreigners were the ones who spread the disease. The Spanish and their Filipino allies carried out a large-scale massacre, in which 17,000 to 22,000 Chinese rebels died.
I used this outbreak as the background for my story, and the rest are just fictitious and are part of my imagination such as names, characters, other places, and events.
Source: https://second.wiki/wiki/masacre_de_manila_de_1820