Jailor's Pox is an affliction that is mostly involved in Bethan the Biologist's story mission in Player-owned ports. Bethan recovers samples from a disease-riddled abandoned ship found in The Scythe region, and deliberately infects Finia with it under controlled conditions in order to test and examine the natural resistances of sea orphans, but Finia escaped quarantine and infected other sea orphans on Hyu-Ji, where the disease mutated enough that it was able to overcome their natural resistances and plagued the island.
Jailor's Pox has been encountered on Gielinor's main continent at least once, as Bethan was able to identify it by its symptoms despite having otherwise not visited the Eastern Lands.
Jailor's Pox has riddling effects on the body which create lateral buboes and give a feverish effect, with a high mortality rate. The ship the sample was taken from had all occupants die to infection, and was known well enough that other ships avoided it.
Jailor's Pox can be cured by using a type of rare flower known as Acralis, which is usually used as a good-luck charm for sailors from the Wushanko Isles. During Bethan's story mission, she acquires a large sample of it from The Bowl region and uses it to cure the sea orphans of the disease before it can spread to the rest of the island.
- Jailor's Pox appears to be similar or identical to the real-life Bubonic plague.