The most recent health epidemic to sweep the world, the Yellow Plague was killing hundreds of people daily across the globe as recently as a few years ago.
Related to Streptococcus pyogenes, which even in the early 21st century was killing 500,000 people a year, the Yellow Plague was much more effective at harming the host before symptoms began to show. The damage to the internal organs, and particularly the liver, caused some of the same symptoms as Yellow Fever, and so the name quickly stuck.
At first barely noticed, cases began to amass in Europe and spread beyond, and more people died from consquences of toxic shock and sepsis. The UN advised a ban on all unecessary travel, but by that point the infection had spread far and wide.
The origins of the infection remain a mystery, but many believe the outbreak was caused by a genetically engineered bacteria that was either intentionally or accidentally released into the population of Central and Western Europe.