The Scarab Plague was an uncontrollable disease that quickly spread to all reaches of Elona between 652 and 656 DR. The disease causes victims to develop scarabs, known as Pestilentix termitroxus, underneath their skin. The bugs then burst from their host's body, causing them to die a horrible death, and carry it on to other people.
The Scarab Plague originated in the city of Fahranur. According to findings of an Elonian scholar, the illness did not spread in a distinct pattern and claimed lives regardless of gender or age, developing more dire symptoms as time passed. Remains found in the ruins supported the claim that insects had torn the victims' flesh from within as the cracked bones were bent and bore spherical indentations. The findings suggested that the creatures responsible may have been scarabs, hence the name of the plague.
Panicked, the people of Istan fled to other parts of Elona, only spreading the plague further. The event ultimately ended the reign of the Primeval Dynasty by wiping out the royal family, leading to an interregnum period which ended many years later when Admun Kolos founded the Great Dynasty which would eventually repopulate Istan. It is still not known how or why the seemingly unstoppable illness vanished.
While exploring Fahranur in 1330 AE, Dragon's Watch discovered that Palawa Joko's Awakened were using Inquest technology within the city to experiment with bugs, possibly related to the Scarab Plague.
During the mission to destroy Joko's portals which he used to invade Tyria in Rata Primus, the Pact Commander and Braham Eirsson rescued Gorrik, an asuran scientist studying the scarabs. Gorrik revealed it was Joko's plan to unleash the plague on to Tyria. The Commander and Braham hurry after Joko and finds him in the containment chamber, holding a small ampoule of the plague in his hand. Before the lich could be caught, he throws the plague sample through a portal with an unknown destination and orders Commander Lonai to kill the interlopers.
Pestilentix termitroxus has a very quick reproductive cycle.
- By the second generation, the larvae are able to exist outside a host. 
- The first and second are not quite so serious, but their existence would, of course, be evidence of the third generation being on its way. Scarabs are at their worst in the third generation.
The Scarab Plague only uses humans as hosts for incubating the next generation whereas other races mainly serve as a food source for the scarabs. Those who have died before, such as the Pact Commander, are avoided by the scarabs who can smell the stench of death.
- ^ a b Forearmed Is Forewarned
- Gorrik: Do it fast. Those scarabs were first generation, but Pestilentix termitroxus has a very quick reproductive cycle.
- Gorrik: Once Joko cultivates a third generation, he'll be able to unleash a full-scale pandemic. We're talking a matter of days.
- ^ Seized Gorrik: And second—do please note this, as the distinction is vital—it's not a plague. It's a pestilence.
- ^ The First City
- Taimi: Experiments... He has them doing experiments.
- Braham Eirsson: What kind of experiments?
- Taimi: I don't know. Bugs. Something with bugs.
- ^ Guns, Germs, and Steal
- Gorrik: If they're in a larval state ouside a host body, they're second generation. Joko must be testing it out there.
- ^ Forearmed Is Forewarned
- Queen Nahlah: No...this can't happen again, Sister...and it WON'T. What you need, Commander, is an army of the dead.
- Queen Dahlah: Which you yourself can lead! Oh yes, Commander, we can smell the stench of the Lost on you.
- Queen Dahlah: Mmm, musky. The scarabs will smell it too. You're an unbefitting host. Lucky for you.