Recombinant yersinia pestis

Recombinant yersinia pestis, also called "the Pest", was a disease known throughout the Third Great and Bountiful Human Empire. It was fatal to humans over the age of ten. In the 78th century, it was curable with a powerful antibiotic, but it was still considered a serious enough disease that planetwide quarantines were used to contain it. (COMIC: A Fairytale Life)

Behind the scenes
Yersinia pestis is the bacterium that causes the bubonic plague.