Alvanian Spine Mites are tiny parasitic lifeforms which burrow themselves into the spinal column of vertebrate species, causing back pain for life. When Odo, a Changeling, having lost his shapeshifting abilities, felt a back pain he believed it was being caused by Alvanian Spine Mites, but Dr. Bashir assured him it was just a pinched nerve.
This species is likely native to the same planet of Alvanian Bees, Alvanian Cave Sloths and Alvanian Brandy, all mentioned in other episodes of Deep Space Nine.