Styris IV

Styris IV was an inhabited Federation planet located in the Styris star system. The planet is also located near Starbase 14.

In 2364, and outbreak of Anchilles fever broke out on the planet. Ligon II was the only planet in the region which was known to have developed a vaccine for the fever, and so the USS Enterprise-D was dispatched to negotiate for a supply of the vaccine. (TNG episode: "Code of Honor")

In one continuity of the mirror universe, Styris IV also suffered an outbreak of the Anchilles fever at the same time as its primary universe counterpart. In this reality, the ISS Enterprise-D was dispatched to Ligon II to obtain the vaccine by any means necessary. The vaccine was eventually obtained after Captain $𝜇$ ordered that the entire souther continent of Ligon II be bombarded by gamma-fission radiation. (TNG novel: Dark Mirror)