it sounds like it could possibly be a threadworm, although threadworms wouldnt usually be solo. pics would have been immensely helpful.
if it happens again, i would try to check it for movement under a good magnifying glass or viewer, would probably also be a good idea to check out his feces under a viewer, thread worms can be visible to the naked eye so you dont need much magnification. the only way to know whats up for sure is to submit a fecal. jmo. how long was it? 1.5 cm you say? hmm, very suspicious! a adult female threadworm can grow to 1.3 cm
threadworms also do not like light, and are most likely light to exit at about 4 am, might not be a bad idea to look at your chams butt and any feces in the cage with a flashlight around that time. also, threadworms are capable of entering through the skin , so gloves and sensible handling procedures would be a good idea, until you find out one way or the other. jmo